This article is all over the place, but the principle is pretty simple - rather than adding more generation for peak usage times, batteries store energy generated off peak and smooth out the macro usage trends.
Our local utility in NC has a program where they'll pay you ~$50/battery/month to enroll in their virtual power plant program. In exchange, they can take control of your battery up to 36 times per year for a period of a couple hours. Summer events are typically early evening during peak air conditioning times. Winter events are typically early morning during peak heating times.
In practice this means one of two things:
* They make your battery charge to full capacity in advance of the event, and then you run your home off the battery and don't take any power from the grid during that time
* Sometimes you'll also return power to the grid beyond that used by your house - they pay you the contracted rate for the power you deliver
We've paired our batteries with solar panels, so generally we have a full charge going into the summer VPP events. We have gas heat, but I expect we'll pay for at least some grid energy to charge batteries during the winter events. Regardless, it's been a good program for us - even without solar, we would not pay for any more power than we used, and the monthly rebate from the utility makes the economics of the system a lot more favorable, especially here in the land of relatively cheap coal power.
Ideally for people with a battery they would take charge to manage your battery between 50%-80% full, paying you for anything you send to the grid. 36x a year means major peak events only (one assumes with a limit of 36 they will try to be under that just in case the last day of the year has a problem). However a 50-80% policy is nice to batteries and means they can use it for even tiny local peak events. Ideally there would be enough home batteries that between all the renewables (Parts of NC are part of the TVA with plenty of hydro) they go months between using a fossil fuel plant.
Not the OP, but I'm on the same program in NC. You can set a minimum level to keep your battery that will cover at least short power outages (mine is set to 20%). You can also decline to participate with a limited number of VPP events a year.
My utility doesn't have a program quite like this, but they do have a peak power rate that incentivizes similar behavior. I have our system configured to charge up to 90% at 12pm, and then consume no grid power until 7pm (peak rate is 1-7pm), or if the battery gets down to 35%.
I also have it configured to charge to 100% if there are any weather watches or warnings. That overrides the time-of-use configuration.
We do also have a generator that I can hook up if the batteries get too low. We have enough battery to get us through the night, but we don't have enough solar to keep up in an outage during the darker months, or if we want to run the A/C.
What is a generator if not a battery that charges with fossil fuels? As long as the battery has enough energy to cover the outage the end result is the same.
Combine it with rooftop solar to get the equivalent of free fuel for your generator every time the sun shines.
> As long as the battery has enough energy to cover the outage the end result is the same.
That is the key—having enough battery to cover an extended outage is very expensive.
My generator can run on natural gas, which is piped to our house and only had one outage in the fourteen years we've lived there (when the gas company replaced lines as part of preventative maintenance). So effectively, we have a redundant electricity source coming into the house. If that was also down, I could also run it on propane or gasoline.
That being said, if I had to pick batteries _or_ a generator, I'd prioritize batteries. We have both, and the batteries cover the majority of outages, while also providing other benefits.
They can, depending on storage and outage duration you plan on mitigating. For example, a friend in ComEd's Northern Illinois service territory has quite a bit of rooftop solar. They subscribed to Base Power [1], who came and installed battery storage on site. Base Power became their power provider, which is a few cents/kwh cheaper than ComEd, because they charge the batteries at night when demand is low and Constellation Energy's nuclear fleet is still pumping out power (Illinois has the largest merchant nuclear fleet in the US [2]). Their daily solar generation is sufficient that if utility power fails, daily solar generation is sufficient (with batteries for coupling to enable continued solar production when utility sync is lost) to not need a fossil generator; the battery will carry them from sunset to sunrise until the solar panels are producing again during daylight hours. "What is your risk model?"
If you cannot install residential solar, don't have enough solar, or have to defend against outages lasting for days or weeks, having the infra available to support an exterior fossil generator is certainly something to consider (main load center transfer switch, receptacle on structure exterior for genset supply to the load center or a subpanel of critical loads).
> They make your battery charge to full capacity in advance of the event..
> We've paired our batteries with solar panels..
Does this imply that the scheme will charge your battery from the grid, and that you don't technically even need solar?
I've never considered that one might get a battery without solar, but I guess you might have some power needs that would make it worthwhile to draw on during cheap periods and drain at peak?
We're in the GMP program from TFA. We don't have solar (it's on the list of longer-term projects). GMP is using the batteries solely to time-shift the load by charging from the grid during periods of low demand and drawing during periods of high demand. It decreases their (and indirectly their customers') costs because peak-rate power is expensive to buy or generate.
(seems like it would make sense for GMP to deploy batteries everywhere commercially logical first wave, and then follow with distributed solar generation across their service territory: https://greenmountainpower.com/map/service-area/)
Solar is very popular in Australia, to the point that we have too much surplus during the day. So now we often have effectively free energy late morning to early afternoon.
So while not common, some people here do get batteries despite having no solar, to store the excess from the grid for when it’s more expensive later.
Correct, solar not needed. Depending on your battery capacity and usage patterns you could enroll in one of the plans that lets you pay cheaper rates off-peak to charge your batteries from the grid, and then power your house off the batteries during peak times. Some places this makes a lot of sense - the spread here (between off-peak, flat rate, and peak) is not favorable enough to make it interesting though, as far as I can tell.
I’m in a similar setup where I live in Australia. Our house has solar and battery — unlike the people in the FA, we purchased it directly ourselves, although with a significant government rebate.
Our battery is under automatic VPP control, but it’s not like it randomly starts exporting when we don’t want it to. When regional demand is high (hot days) or supply is low (no wind or cloudy), our battery might start exporting. But that’s a good thing for us, because our electricity is priced wholesale and changes every 5 minutes, and export rates are high in this situation. A couple of times there have been price spikes and we’ve made a few hundred dollars in under a hour. It’s a win-win for us (making money) and the grid (providing stability). To be fair, those spikes are rarer now than they were a year ago.
You can always control the battery if you want. Sometimes I’ll manually export even if prices aren’t high if I know I don’t need the power in my battery. Sometimes I’ll prevent export if I know I want to charge the car overnight from the battery. But mostly I let it do its thing.
From an investment perspective, the battery has been a no-brainer. Even without the windfalls from price spikes, being able to defer grid consumption to daylight hours (when wholesale prices are very cheap or even negative, i.e. we get paid to charge the car) puts the ROI in the 3-5 year range.
Amber is my retailer, and it’s their SmartShift VPP system that controls the battery to minimize grid consumption and maximize export revenue. The battery/inverter system is SigEnergy.
Orthogonal but related: where I live, homeowners might get charged negative prices at times for solar re-injected in the network. This doesn't make a ton of sense for me since you could just unplug the panels instead of being charged for the production! However, the electric company charges you retroactively (on a 15-min bucket) so you would need an accurate model to "beat them at their game". Negative electric prices in a country with a huge amount of solar/wind/hydro is surprising, since all of these production methods can stopped on demand (and even reversed in the case of some hydro setups).
This is the case for us, too. The reason is that whenever there is more supply than consumption on the grid the excess must be shed, and that costs the utility. Hence negative export prices to discourage supply to the grid.
Our battery/inverter system automatically curtails solar generation when our battery is full and export prices are negative, so this isn’t anything we need to think about. (Exception: I’ll charge the car to drain the battery overnight if I expect curtailment the next day. No point letting all that free sunshine go to waste!)
The negative price can either be from subsidized renewables that are passing some of that subsidy onto people who use the power (a good thing!) or remaining coal plants that can't flex fast enough and would rather pay than incur extra costs from flexing (which is good in that they are being effectively fined for lack of flexibility but bad in that they are inflexible and still generating dirty power while more flexible renewables curtail).
If clean energy is being curtailed increasing usage is a better response which negative prices also incentivize but in many jurisdictions they refuse to pass those price signals onto users because they'd rather waste clean energy so they can sell them dirty energy later.
In Australia it's not uncommon on moderate temperature sunny days for the wholesale price to enter the negatives. Lots of solar production, with minimal heating and cooling demands.
Many plans offer a 3 hour period where electricity is free to encourage shifting your load to that time. Which is amazing if you're able to charge an electric vehicle in that time, a standard single phase charger could provide 21kw/h in that 3 window all for free.
It's interesting that we're seeing situations now where we have excess energy, and can't think of a good use for it that doesn't just involve storage.
Kind of like a home energy dump that does something tangible, like bake a potato or something. You could come home in the afternoon and be rewarded with a reheated meat pie, or some chips that are automatically dumped into an air fryer.
I've heard that aluminum smelting makes for a good "energy dump" and actually is almost more important to the economy at energy price aribtrage than as a source of aluminum. But Iceland and a few other places have already taken a lot of this market and maybe we already have as much aluminum smelting as we need.
Maybe I’m not picturing it correctly but wouldn’t a negative price mean more money in your wallet? Or are you saying that the set price is less than it costs to produce the energy on your side?
> Situated on 8 acres of industrial land, the Kapolei Energy Storage project comprises 158 Tesla Megapack 2 XL lithium iron phosphate batteries, which are about the size of a shipping container. All told, the KES project provides 185 MW of total rated power capacity, or the largest possible instantaneous discharge, and 565 MWh of energy capacity, or the maximum amount of stored energy.
> The system can meet 17% of Oahu’s electricity demand for three hours at peak load or six hours at half load, Brandon Keefe, the executive chair of Plus Power — the company that developed the project — told USA Today. Plus Power “develops, owns, and operates standalone battery energy storage systems that provide capacity, energy, and ancillary services, enabling the rapid integration of renewable generation resources,” according to the company’s Jan. 11 news release announcing the start of operations at its KES facility.
The amount of power rooftop solar in Hawaii is allowed to export to the grid is regulated.
> Customers enrolled in NEM Plus Limited Export are required to install a control device at the utility meter to limit the combined export capacity of the existing and additional generation to the capacity of the original NEM system. The battery must be programmed to 'load-following' mode so as not to export to the grid -- except when providing exports for grid services.
> Lately though, electricity, not recreation, has become the big-ticket wind client in the Columbia Gorge. Wind turbines have sprung up all over the blustery hilltops in eastern Washington and Oregon, an area soon to become home to the largest wind farm in the world, developed for customers of Southern California Edison. Indeed, half the massive new wind power generated in the Pacific Northwest goes down the grid to California.
> For the last three weeks, however, many of the wind farms have been ordered to shut down their generation for several hours a day — victims of an unusual surplus of hydroelectric power that has confounded regional electricity operators and infuriated renewable energy advocates who have worked so hard to develop the region’s wind bonanza.
> The problem is an unexpected collision between two of the Northwest’s most treasured environmental assets, wind power and endangered salmon. Spring flows on the Columbia are so high that power system operators say they cannot dial back hydroelectric generators without harming the small juvenile fish now making their way down the river in their spring migration to the sea. With the turbines generating so much electricity, there is much less room on the grid for wind power.
---
In some areas, hydro is coupled with environmental regulations. You can either use the water for power (doesn't mix with the air when doing so), or have it go over the spillway (substantial mix with the air).
The hydro plants, during periods of time when fish are swimming upstream are regulated on how much they can have go over the spillway - and so are forced to generate power... and potentially more power than the demand calls for, and so you've got negative rates.
> BPA insists it can dump only a limited amount of water over the dams because excess spillage creates dangerous levels of nitrogen that are harmful to salmon and other fish. The curtailments may defy an order from the Federal Energy Regulatory Commission (Ferc), which ruled in December that BPA, as operator of 31 federal dams and much of the regional grid, cannot discriminate against wind power by forcing unilateral shutdowns. Several factors have changed since last year, but wind generators still stand to lose millions of dollars.
Another aspect of this is timing. Solar and wind have peak power at different times (and different times in relationship to demand).
> But notice that the thermal generation (nuclear, gas and coal) does not vary much at all. It is the hydro component that has to constantly cycle up and down to adjust to the demand and to wind’s intermittent supply. This competition between two renewable sources means that the relatively carbon-free accruable hydro energy must be shed to take on the wind supply, with no net benefit in carbon emissions or energy cost.
> But constant cycling between 2,000 and 4,000 MW produces significant wear on the hydroelectric turbine gates.
> The following graph compares wind energy production and total demand (or load) for the first half of January 2014. Wind is weakly, but negatively, correlated with demand, meaning wind energy generally comes onto the grid when it’s not needed. Thus the constant need to ramp down hydro production to accommodate.
> Solar coupled with storage technologies could alleviate, and possibly eliminate, the risk of over-generation. Curtailment isn’t necessary when excess energy can be stored for use during peak electricity demand. SETO launched several projects in 2016 that pair researchers with utilities to examine how storage could make it easier for utilities to rely on solar energy to meet customer needs around the clock. This research will enable even more solar energy to be integrated into the grid, while tackling the obstacles utilities face when incorporating solar.
Though this will be something to look at for in the winter with "how does the house get heated?" https://www.maps.com/home-heating-fuels/ - This likely won't impact New England too much as that's primarily oil, but it's something to watch for. The "batteries with solar backup" would have more difficulty if there was increased demand for electric heating and reduced solar production.
Absolutely. It’s amazing here how government incentives to install batteries have led to stabilization of the grid. Power outages are pretty much a thing of the past now.
Here in Belgium, there's "a bit" of asymmetry: the price per kWh I pay from the grid is roughly 3 times of what I get when I inject. I also have a fixed cost per year to have the right to inject. I knew this before I installed solar and have a home battery, so it only happens during summer.
Distribution charges are per kwh and vary by the hour (more expensive in high-demand morning and evenings, lower during the day and at night). The spot price has to be high enough to exceed the distribution charges for net income on export.
Most of the time, distribution charges are higher than the spot wholesale prices for import and export.
Seems like they supply each person with 2 Tesla powerwalls for the $55/month and get a reduction in their bills that depends on how much power they choose to share to the grid during power outages.
They've already closed down 2 peaker power plants because of this, so it doesn't seem to just be about handling power outages, but also handling fluctuating power usage instead of firing up extra power plants.
>They've already closed down 2 peaker power plants because of this, so it doesn't seem to just be about handling power outages, but also handling fluctuating power usage instead of firing up extra power plants.
Yes, that was a significant early argument I remember around the public benefits. The daily power spikes have always been a major challenge particularly when you don't have much commercial/industrial base. And even in the earliest period of the original 2000 home pilot they were surprised and pretty happy about how much load could be spread and the resulting savings. Note though that regulators were cautious and there was controversy around how well it'd actually work, you can find articles like this 2019 VT Digger one [0] from the era. Fortunately it did indeed work out, but easy to forget it was all pretty new at one point.
I was thinking exactly about this when reading the article. The article writes about house owner benefits but it's the benefits of reduced peaks that are more likely to make providers wanting to do so. With this in place, power plants can take half an hour to increase their generation and top up the battery, instead of having to have faster plants round that caters to peaks.
We're in the program. The powerwalls don't share to the grid when there's an outage. We don't get a direct reduction in our bill for having them. Everyone on GMP gets better rates because GMP isn't buying power wholesale at peak rates or generating it with peaker plants.
Lithium is not the way to go for home batteries. As size/weight are not an issue for a basement or shed install, oldschool lead-acid are much cheaper and can be easily recycled once at end of life.
Those tesla wall packs will be a massive headache when they give up the ghost. Read the contract carefully. Who is responsable for end-of-life disposal? Where/how are they to be disposed of? Lead acids can be taken to any number of recycling centers, some will even pay you for them.
We're in the program. As written, it's a 10 year lease, and there's no option to buy-out the equipment at the end. We'll see if they offer that as an option as the end of the lease approaches in another 7 years. For now though, GMP is on the hook to come and get the equipment.
I would also suggest that size and weight are bigger concerns than you're giving credit to. They aren't assembling packs on-site from individual batteries. They're rolling in whole-ass packs in one swell foop. Getting them into basements isn't a small job[0]. Getting them back out will be even less fun for the crews.
Their total on-site install time was maybe 6 hours, and that included tying everything in to the existing system. Putting the hardware in place took maybe an hour of that time. If you want to go with heavier packs or more/larger packs, you're going to add to that a bit. And their doing this in people's finished homes. This isn't new build where they can have a couple of big dudes wrangling packs around without a care in the world for furniture and finished surfaces. The ergonomics of smaller packs matter.
[0] They used a two-wheel dolly with a hydraulic disc brake (bicycle hardware) to get them down our basement stairs.
If the utility owns the packs, part of me wonders why not build out battery stations around substations the utility already owns, instead of managing many small batteries in individual houses.
Seems like the former would have some development costs but ultimately be cheaper to manage
Doing it that way they couldn't charge a lease to the homeowners. By leasing the batteries to the homeowners they're offsetting some of the cost through that lease, but also the selling point for the homeowner is they (presumably) now have a backup in case of a full outage
Also, you're reducing demand on the grid by having them at people's homes, not just reducing the demand on the power plants. If the batteries were centralized you'd still need to move that massive amount of power over distribution and transmission lines, which is actually just as big a problem as needing to spin up a peaker plant. In many areas the bottleneck is transmission not generation
Long term, with people moving towards charging their cars at home, storing excess solar energy at home might be the more economical option because it decreases the amount of power a substation has to send out at peak times.
I guess Vermont’s relatively low population density makes that more likely; with lower population density each service station will either service fewer homes or require more cabling towards those homes. Either way, more cabling is needed per house. Upgrading that to handle the load of charging a car can be costly.
2-wheel dollies with motorized stair climbers are a thing too. Not super common, but aren't cost prohibitive for a use case like this where they'd see daily use.
Seems like recycling is picking up for lithium batteries and the metal components are still valuable enough.
I think a bigger question is if sodium batteries starts to take over (seems better for homes, heavier but seemingly safer but also for cheaper cars) and lithium/rare-earth metals prices goes down.
Lead-acid batteries are amazing for starting an engine, and terrible at basically anything else. They're slow to charge and very sensitive to over-discharge: it's generally recommended to never go below 50% state-of-charge (so you basically need twice the capacity in the first place), and even one full-discharge event will permanently reduce their overall capacity. The fact that they're almost impossible to over-charge means they're never paired with a proper BMS so they usually aren't protected against this type of damage. Also they need to be fully-charged every few days, so they're a poor choice in an application where they're constantly cycled.
Lithium batteries in contrast only need a ~10% buffer, and don't care about being topped off except for calibrating the BMS in certain variants (the only reason why LFP cars want you to charge to 100% regularly), so you don't have to over-provision as much. End-of-life is being sorted out as we speak, recycling companies are popping up as discarded batteries from cars are becoming common. Some may even pay you for them too.
I was looking into this stuff early this year in India, and found LiFePO₄ more compelling on paper: two or three times the cost, but lasting two or three times as long, allowing deeper discharge so it should be equivalent to slightly higher capacity, and requiring no maintenance. I could easily have overlooked or misunderstood something, and am interested in counterarguments.
The lifespan numbers are lies. I have personal knowledge of deep cycle lead batteries lasting 10+ years, thousands of cycles. Many websites actually cite numbers for sealed batteries as used in cars. "Flooded" batteries last longer than sealed because they can be inspected and maintained. There are also "deep cycle" and "marine" units which are also different than car batteries and can be discharged more.
I’ve seen and heard of a lot of lead-acid battery home inverter and desktop UPS setups in India (extremely common due to grid unreliability). Desktop UPS batteries sound to consistently be completely useless (<10% capacity, typically 0%) in 3–5 years, and the larger home inverter batteries are typically in poor shape by around 5 years.
I haven’t known any Lithium-ion batteries yet, so I have no personal figures on them. But what I’ve heard is generally more like “they said 8–10 years but it’s still fine after 12”.
lead-acid does not like deep discharge. Also a UPS is typically going to have maintenance free batteries which don't last as long. Many UPSes don't have good chargers and will overcharge your batteries.
You can get decades our of a proper lead-acid battery, but only if you correctly account for all those factors. Start with batteries that you add water regularly (I'm not sure if this is monthly or yearly). Then make sure you have more than enough so that even in the worst case power outage they finish at 30% charge (meaning most don't get close to 50% discharge - the 30% an educated guess but needs more research for your conditions since this needs to be a rare event, the more often you get the worst case outage the more charge needs to remain after). Finally make sure you have a good chargers - modern "battery tender" (a brand name - there are others) makes a big difference.
Lead-acid has been used in major large installation and have a long history of lasting for 20 years when treated properly.
Lithium batteries are still new enough that we don't have a history. We have educated guesses, but those guesses tend to be conservative. Maybe they will turn out to last just as long or even longer. Only time will tell if they are as good or not. However we also know you can abuse lithium batteries and get much worse life. (the Nissan Leaf is famous for significantly worse capacity at 8 years)
The whole depth of discharge thing does make it harder to compare them. I said upthread “slightly higher capacity” for LiFePO₄, but I feel like by recommendations I’ve heard it’s more like 20–40% higher, which is really quite a bit.
Offgrid garage tested it a couple of videos ago and basically the battery lost capacity due to age and not for cycling. And that battery was made with the first generation of lifepo4 from eve, recent battery are better. Realistically it will die first the BMS than the cells in a couple of decades
There are too many variables to make a simple statement. Lead-acid is a lot cheaper and we know how to recycle it. We also have a long proven history of lead acid lasting for decades in ideal conditions (which a house battery is more likely to hit than in a car).
However lead-acid does not like deep discharge so to get max life you will be using much less than the full discharge cycle 80%-100%, and so the lifecycle costs are very different. In some cases lead-acid can be more cost effective if you manage it well, but I would expect lithium to be cheaper for the typical case.
That is lead acid means your real goal is a cheap home backup, which you have to ride out multi-day power outages, and as a secondary you will sell some power to the grid, but you are not trying to make money doing this. By contrast I would expect lithium to make sense if your primary goal is to make money (or at least pay for your home backup system that can ride out a couple hours of outage but not days). The storage to ride out days could work now, but long term as your neighbors buy the system eventually there isn't the need for that much storage and someone gets limited.
Not in homes. Density is a huge issue for commercial installations. The off-grid community also values user-repairabilty and avoiding vendor lock-in. Good luck replacing a dead cell in a tesla pack.
The market for this isn't the off-grid community. It's basically every GMP customer.
You aren't wrong about part of the off-grid community not wanting this. I'm not sure I'd want it if I were doing an off-grid install, but it does stand to grow the off-grid community to include people who are looking for a turnkey solution instead of having to do all the research to put together a more user-maintainable system.
Isn't the Tesla pack just a bunch of 18650 (or some similar cell)?
I wouldn't expect the home owner to repair them. However they should be repairable by someone with training in how to diagnose and replace failed cells. (which mostly means a battery welder and some safety systems)
I'd feel better about this if they weren't charging people thousands for the batteries. As it is, this looks like a scam by utility companies to force their costs onto consumers and charge them for it on top of that. People should be being paid by the utility for storing, hosting, and allowing access to the power company's distributed infrastructure.
It's not as if the batteries people are paying for become their property, or are only for the homeowner's benefit. The utility company has the right to use that power however they want at any time including the "right to use all the energy in the battery". The homeowner also has to allow contractors, subcontractors, or third-parties onto their property. Physical access aside, they also have to allow the utility free access to their network and free use of their internet connection/bandwidth. The utility will not compensate homeowners for any of that.
Homeowners must also agree to install the utility company's cell phone apps/software. I'd bet those apps are collecting data and probably pushing ads too. They have to agree to the “Customer Privacy” terms, which will only be shown to them "upon installation of the Equipment".
The utility company advertises this as a means to prevent power outages (which, if they were doing their job in the first place, should be extremely rare occurrences), but the fine print makes it clear that homeowners should not assume that they will have any access to the power that battery holds in the event of a power outage or at any other time.
The utility also requires homeowners to agree to terms that state the utility will not be liable for any damage to persons or property caused by use of/replacement of/repair of/or the utility's failure to repair the utility's equipment and software. The homeowner also "bears the entire risk of loss, theft or damage" to the utility's equipment.
This would be a bad deal even if the utility were paying a monthly fee to homeowners. The fact that they've conned customers into paying the utility for using them, their internet, and assuming all liability/responsibility for the utility company's hardware is insane.
>I'd feel better about this if they weren't charging people thousands for the batteries. As it is, this looks like a scam by utility companies to force their costs onto consumers and charge them for it on top of that. People should be being paid by the utility for storing, hosting, and allowing access to the power company's distributed infrastructure.
I participated in this program early on (currently on year 8 or 9) and I don't think you're giving a fair characterization. First, the batteries took the place of a generator, and have reliable protected my buildings from power outages since. Part of the program is that in case of storm warnings or other risk it actually switches out from the VPP for the duration to protect you instead. So there's direct value to having them, particularly in a rural area of a rural state, regardless of any other money. Having a sizable generator isn't free, not just in terms of purchase but in terms of
Second, the utility did in fact pay with a pretty massive discount (around $5-6k per battery at the time IIRC). The amount they were willing to pay wasn't enough to completely cancel out the battery cost back then, but it was like 70-80% of the cost. And in general looking at all the various VPP programs in the region utilities remain very much willing to pay you per kWh, whether it's a lease or BYOB.
There are multiple ways to make a battery work for you in terms of ROI, and the math has changed over the years as various component costs have changed as well as being individual to each person's situation in terms of their own usage patterns and generation. But I don't think this was a scam at all, it was a genuine win/win even before getting into softer factors like reducing usage of fossil fuel peaker plants that a lot of us do really care about. In an ideal world neutralizing that carbon pollution would all just be built into pricing so the market could better sort it out, but as it stands I don't feel bad about supporting a shift to some extent too. And even though I'm probably going to just buy my own batteries next time around due to other changes, I'd certainly consider contributing to a VPP again depending. It's been a positive experience.
>The utility company advertises this as a means to prevent power outages (which if they were doing their job in the first place should be extremely rare occurrences)
This is just really hard in some parts of New England given the history of grid development (we have a lot of really weird legacy layouts), weather, trees, population density, and lack of resources. If you're at the end of a quarter to a half mile driveway in the forest up a steep mountain dirt road and aren't able to bury the lines then it can be tough in storms. Plus other weirdness, last year a pole came down and it turns out bears had been using it as a scratching post and just ripped through the entire thing. Was actually pretty cool but also a power outage.
>but the fine print makes it clear that homeowners should not assume that they will have any access to the power that battery holds in the event of a power outage or at any other time.*
In all these years it's never once been an issue though. And I don't consider that "fine print" but obvious: if you're participating in a VPP at all, then obviously there will be times when your battery has been drawn down. That's the deal duh. And with the best will in the world they can't predict things like some drunk driver taking out a pole and causing an outage (this happened again not that long ago). It's not impossible that there could be the bad luck of that happening right when the battery happened to be down to a low level. That's the risk. But they do pay you for it. And almost any way you'd make batteries pay beyond power protection entails some risk or else some cost too, like if you want to rate-shift so that you only pay the lowest night time energy rate by charging then and then running off your batteries during the day, then you'll of course be at risk of lower remaining storage if there's then a grid failure too when you were expecting to charge back up again. You can spend money on that risk in turn, but there's no free lunch here.
> it was a genuine win/win even before getting into softer factors like reducing usage of fossil fuel peaker plants that a lot of us do really care about. In an ideal world neutralizing that carbon pollution would all just be built into pricing so the market could better sort it out, but as it stands I don't feel bad about supporting a shift to some extent too.
We should be doing this as a society (or as a state or as a utility company) instead of relying on individual do-gooders to pay for it. 70-80% of the cost sounds very good, but if you're not getting any latitude on how the things are used, that 20-30% is still unfair. If they belong to the utility, the utility makes all decisions regarding it, and you are giving up your space for it, if anything you should be getting paid, not paying.
They could at least let you actively decide if you want to allow it to be drawn down and to what extent; some sort of latitude. As it is, for them it's money for nothing.
That being said, the article says that they're starting to install them for free. Thanks for sharing your experience.
It's not really a solution for the utility, it's a solution for the homeowner. The utility can't prevent all power outages or issues for all customers. Normally the homeowner buys a generator to deal with that. The battery is cheaper over time, much less maintenance hassle and less dangerous. The customer just wants their lights to stay on, they don't care how that happens.
> They could at least let you actively decide if you want to allow it to be drawn down and to what extent; some sort of latitude. As it is, for them it's money for nothing.
Is there possibly a breaker connecting the home mains with the grid? Which side of the breaker is the battery on? Will the system continue to output even if it doesn't have a reference AC waveform from the grid?
>We should be doing this as a society (or as a state or as a utility company) instead of relying on individual do-gooders to pay for it.
Sure, but we aren't yet, at least not remotely to the extent required. And we all individually have benefited from the externalized pollution that fossil fuels have been responsible for, this isn't just some nebulous other thing right? It's not unreasonable imo that yeah, we individually should try to pay for that damage we ourselves "profited" from, even while simultaneously trying to vote and organize towards broader solutions. But feeding money into getting off fossil fuel is both directly personally helpful and broadly helpful.
>70-80% of the cost sounds very good, but if you're not getting any latitude on how the things are used, that 20-30% is still unfair. If they belong to the utility, the utility makes all decisions regarding it, and you are giving up your space for it, if anything you should be getting paid, not paying.
I don't agree with you, and it's my money, my buildings and my call to make. I've gotten a plenty solid direct benefit in ROI over the last 8-9 years for the $3k it cost me one time only vs the $15k a couple of PowerWall 2s would have been upfront and then the rate shifting and minimal solar I was in a position for at the time, or alternatively the cost of a new generator and then all the fuel and ongoing maintenance required. The $12k in savings thanks to the utility is money I could put into other investments that have had their own ROI since then. I do think the math now for me and a lot of others is different in 2026 then 2017, there are lots and lots of competitive battery and solar and inverter solutions now at radically reduced prices and that seems to just be accelerating, with sodium based systems and other tech coming. But that wouldn't have offset a real chunk of 9 years of carbon equiv release by me. The batteries got far more usage as part of a system for society then just me, and I still did ok even if it didn't perfectly maximize the individual dollar savings.
>They could at least let you actively decide if you want to allow it to be drawn down and to what extent; some sort of latitude. As it is, for them it's money for nothing.
If you BYOB you do get that choice, though obviously if you let them take less they pay less. But it's not money for nothing, just a weighing of risk/benefit.
>That being said, the article says that they're starting to install them for free.
The battery cost per kWh has fallen enough and I think they've gotten comfortable enough with the landscape shift that I can see that making sense now, not early adopter territory anymore. The utility is also in a position to realize benefits like having a bit more leeway in how they dispatch linemen for repairs, if they know someone is covered for 20 hours and it's currently 15 below zero with whiteout conditions that'll clear in 2 hours maybe it's worth something to be able to not have that be an emergency (or instead to direct emergency efforts to someone else who isn't covered).
>Thanks for sharing your experience.
I'm glad it's come up on HN. It's one of the few real rays of hope I find in all this, that despite failure of collective action it's just getting so good that the economics and politics are tilting anyway. Won't be fast enough to avoid a lot of bad effects, but it can always get worse so the faster the better.
> First, the batteries took the place of a generator,
The generator would have been yours, and only used for your needs. It wouldn't have involved any data collection, the uncompensated use of your bandwidth, or exposed you to so much liability.
> Part of the program is that in case of storm warnings or other risk it actually switches out from the VPP for the duration to protect you instead.
They may do this, but by their own terms they aren't obligated to. The good news is that in the event where a cable is cut/down and they lose the ability to siphon power from your battery you will be sure to get the benefit of whatever power it has stored. It's also nice that they compensate you for the power that they draw, but again, all of that energy is already theirs by right.
The state contracts them to provide the people with reliable power and you pay them for that service. They should be expected to reasonably deliver that in exchange. Installing their equipment inside people's homes can be part of how they manage that responsibility, but it's still their responsibility and they should compensate you for that and not expect you to pay them even more for the privilege of paying their costs and accepting liability.
> it was a genuine win/win even before getting into softer factors like reducing usage of fossil fuel peaker plants that a lot of us do really care about.
It's honestly not a bad idea conceptually. It seems like it can have real benefits, but the terms are exploitative. At a minimum they should be obligated to prioritize your power needs above others when it comes to energy stored in the battery on your premises, and they should be obligated to compensate you for power taken, as well as for providing them storage, access, security and bandwidth for their equipment, and they should also assume responsibility for any damage/harm their equipment causes to your property and anyone one on your property as long as it wasn't caused by tampering or improper use. Ideally, you'd also be able to opt out of all personal data collection (not related directly to the use/monitoring of their hardware), and any loss/theft/damage would be covered by their insurance (provided their equipment was reasonably secured), otherwise they'd have to pay you enough to get additional insurance coverage of your own.
I'm glad it worked out for you when you had it, but unless the terms were very different from what they are today you were absolutely cheated and being taken advantage of, even if you didn't feel that way.
Data collection is very useful and valuable to you when done right. We need to ensure the data isn't abused, but that doesn't mean data collection is bad when the data is used correctly.
The utility is well aware that power outages happen and make their customers mad. They want to solve them, but they also know cost matters and so that takes many ways to solve power outages out. Data used correctly from systems like this make power more reliable and it can be cost effective. By giving the utility access to this data they can better serve everybody.
Again, the key is that the data is used to serve everybody and not used for any of the abuses it can also be used for.
IIUC, the benefit for the customer is a battery backup that is much cheaper than buying the batteries themselves would be, plus the ability to make money when their battery is taken over for a few hours during occasional peak usage events. Provided the former override the latter, as seems to be the case, I don't see what the issue is.
I think you're claiming that battery backup shouldn't be needed in the first place if the power company was doing their job properly, since then there wouldn't be frequent outages in the first place. But I gather that this just isn't practical in rural Vermont. To put it another way: In that environment, a power company guaranteeing 99.999% uptime could not offer this at a price that is acceptable to most customers. So the equilibrium naturally shifts towards citizens tolerating more frequent outages than would be tolerated in, say, central NYC, and/or paying for mitigations like generators or batteries.
> IIUC, the benefit for the customer is a battery backup that is much cheaper than buying the batteries themselves would be, plus the ability to make money when their battery is taken over for a few hours during occasional peak usage events. Provided the former override the latter, as seems to be the case, I don't see what the issue is.
They don't get a battery backup. The utility company gets a battery backup and the customer pays a large percentage of that cost. The utility company isn't obligated to let the consumer who paid for part of that battery draw power from it, ever. They explicitly state that all the energy it stores is theirs, and that they can drain all of it away any time they want to.
Customers are being contractually obligated to shell out thousands of dollars, over a 10 year commitment they're punished for backing out of, obligated to not hold the utility company responsible for any damage they cause, obligated to take on a bunch of liability for things they have no control over, obligated to allow the company access to their property, obligated to allow the company access to use their internet service free of charge, and for all of that the utility company isn't obligated to do anything but install the company's equipment on the customer's property
All the customer gets is that maybe they'll be paid for the power the company takes from the battery (the company doesn't have to pay anything) and to maybe get to draw power from it if there's a service outage (the company isn't obligated to let them use any of it).
There are customers who say they are being paid for that energy and they have been able to use the power to avoid outages, and that's great, but that can change at any time and for any reason because the terms they agreed to don't obligate the utility to do either of those things. The terms explicitly say that all of the energy in the battery belongs to the utility company and they can use it however they see fit.
Maybe this utility company is the nicest company in the world. Maybe the utility company today would volunteer out of the kindness of their heart to rebuild someone's house if a software update causes the battery to catch fire and the customer's home burned to the ground along with everything in it, but the terms say they wouldn't have to do that and couldn't be made to. Maybe the company would never ever stop paying customers for the energy they take, or leave the customer without power while they drain the full battery to help restore service for businesses or wealthier customers. The terms would let them do those things though.
You shouldn't pay out thousands of dollars, take on a list of obligations, and expose yourself to huge risks and liabilities and then still be forced to just hope that the company will do the right thing, and keep doing the right thing for the next decade of your life. That's the problem.
>The generator would have been yours, and only used for your needs.
It also would have required constant testing and cost whether I used it or not, with no ROI whatsoever beyond power backup, a lot more noise/local pollution/size, storage of significant amounts of extra fuel (be it propane or diesel) with the resulting challenges, etc. Maybe the best bet and the one I was most strongly considering would be a PTO generator I could hook my tractor up to, then I'd get all the engine testing and fuel refreshing/storage "for free" on some level, in that I run the tractor anyway. But that still would have been dead cost most of the time, and on a basic but real human physical level, having to go out to the barn to hook things up and unhook them in the heart of winter wasn't a delightful prospect either. Propane doesn't go bad and maybe I could have finagled that into my heating system for a unified tank instead of multiple but that's still its own complexity, and place to house it and so on. And in retrospect that would have reduced the value of the heat pumps I've done since.
Batteries are nice. And I'm glad it wasn't only used for my needs. I like helping my neighbors, my town, and my state.
>It wouldn't have involved any data collection, the uncompensated use of your bandwidth, or exposed you to so much liability.
I'm definitely sensitive to data collection, and full local control has always been something I've cared a lot about and is a significant consideration going forward. But I've got the PW isolated on its own VLAN going through my OPNsense router, and the granularity of its perspective is I think pretty course. Given what I'm running I just don't think there's a whole lot, if anything, it can glean the power company couldn't already, it's pretty out there on the master panel so it doesn't even see just the house, use from the barn and office and so on is all mixed into the signal. Taking into account what was on offer and far tighter finances at the time I think I did the best I could.
This is also a case where I think some level of regulated, low granularity population data may be pretty important in terms of infra planning our shift to only renewables and a smarter grid. I'll have to keep thinking about that though.
>They may do this, but by their own terms they aren't obligated to
I'd have to double check if my terms from back then are different then what they offer now, but ultimately the fact remains that across hundreds of outages and blips over 8-9 years with a couple of devastating floods and storms in the mix it has never been an issue even once. These aren't megacorps, utilities here are pretty tiny by national standards and pretty responsive (as well as regulated).
>The state contracts them to provide the people with reliable power and you pay them for that service. They should be expected to reasonably deliver that in exchange. Installing their equipment inside people's homes can be part of how they manage that responsibility, but it's still their responsibility and they should compensate you for that and not expect you to pay them even more for the privilege of paying their costs and accepting liability.
GMP has I believe something like 10,000 miles of pole distribution lines for 265000 customers, but of course those customers are not evenly distributed, there are towns around here with literally double digits of people. And it's the biggest one, there are tons of smaller outfits and coops etc. "Reliable" doesn't mean "perfect" and never has, that's just not possible at the prices people can afford here.
I mean really, on some level everyone needs to be ready to contribute in general for life here sometimes. State is responsible for roads and such too, but if it's bad I and others get out our chainsaws (now electric! electric chainsaws are AWESOME) and winches and so on and get to work. State police provide coverage and will respond eventually, but it might be 30-120 minutes (or more sometimes). I've taken first responder courses, folks volunteer for fire departments and other roles, folks have guns. Others who can't do any of that can still bring people out clearing trees hot food and drinks and general support and that's a serious contribution and appreciated too. Dunno, not saying utilities shouldn't keep pushing hard and being pushed, nobody wants to be a floor mat, but I feel like they've been pretty solid and they really have been trying hard over the last few decades.
>It's honestly not a bad idea conceptually. It seems like it can have real benefits, but the terms are exploitative.
Some of your list feels like reasonable avenues for improvement, others feel totally unrealistic to a degree that it'd really end of restricting who could benefit. I don't think the juice would be worth the squeeze there. But BYOB is an option with a self-consumption plan, where rather then supplying power back you instead basically get disconnected from the grid during peak events, see [0]. The terms and conditions aren't nothing, but power infrastructure is pretty serious business and I'm not sure it's reasonable to expect the utility not to want some pretty clear control and terms around it. And if you want out of it looks pretty reasonable, 30 days notice and you pay back a prorated portion of upfront incentives and that's that.
Also, "bandwidth", seriously? I'm looking at Netflow for the electric infra VLAN and it's like, 1.5-4 kbps, with occasional spikes to... 25 kbps for like a second. Yeah we're the boonies and progress is slow, but nice outfits like NEK Broadband [1] have been working hard and we've got fiber now, and of course Starlink is an option, sometimes even cellular. But even on crappy old 5/1 ADSL like I had to live with for 20 years it's not much. Come on. Rural America isn't that far back, we've gotten a ways beyond 14.4k modems.
You and I live in areas where social norms are to help our neighbours and contribute to our communities. GP seems to live in a place where relationships are contractual - he pays taxes and expects to be served in return with no effort on his part.
Often people from different societies have difficulty understanding how anyone "could live like that" - in both directions.
Helping neighbors and contributing to communities is great! Getting taken for a ride by a utility company isn't either of those things. The relationship with their utility company is literally contractual. They make you sign a contract! A contract with very bad terms. They're pushing some of the typical costs of running their business onto their customers, leaving them entirely responsible in the event that anything goes wrong, even when their customers do nothing wrong and have no control over the situation, and they are making the customer pay them for the privilege while not being legally obligated to provide anything in return.
Also yes, paying taxes should entitle someone to basic minimums like the ability to pay for clean drinking water delivered to your tap, and reliable power delivered to your home. We aren't a developing country, we're the richest nation on Earth. The extent of the "effort on my part" should be limited to signing up with the utility company and paying my bills every month. Everything else is their job. It's what they are paid for. What "effort on your part" are you making in your life to help your water company? Your cable company?
I am struggling here too. I think there are some decent points at the margins, but I can't get past the idea, "If this is the one place I am being exploited, I would be pretty ok with that."
> It also would have required constant testing and cost whether I used it or not, with no ROI whatsoever beyond power backup, a lot more noise/local pollution/size, storage of significant amounts of extra fuel (be it propane or diesel) with the resulting challenges, etc.
According to the utility company you should have one anyway because you may not have access to the power available in your battery even when it is full. Even when you need it, they can decide to send it somewhere else.
> And I'm glad it wasn't only used for my needs. I like helping my neighbors, my town, and my state.
In this case you're also helping your utility company and being charged for the privilege. How often have they helped you with something you weren't paying them for?
> These aren't megacorps, utilities here are pretty tiny
Your energy company is a subsidiary of Énergir. It's the largest power company in Vermont providing service to the vast majority of the state. They also provide power for New York, Maine and Connecticut. Énergir is also the largest natural gas distribution company in Quebec. This is not a local mom and pop operation.
> I mean really, on some level everyone needs to be ready to contribute in general for life here sometimes. State is responsible for roads and such too, but if it's bad I and others get out our chainsaws (now electric! electric chainsaws are AWESOME) and winches and so on and get to work.
How much do your neighbors charge you when you help clear the roads with your chainsaws? Do they make you legally liable for any damage to cars if there are accidents on that road after you helped clear it? Would it be absurd if they did?
If you really want to volunteer to help host/power/secure/connect your utility company's infrastructure for them that's very sweet of you, I'm sure that will save them a lot of money, but they are also charging you a bill to do it for them and then they're leaving you liable for things entirely outside of your control while also making you agree that you'll be responsible for any harm caused by their equipment. They aren't being your friend here. They aren't looking out for you. They aren't acting like a part of your community. They are charging you and your state money, externalizing some of their costs and risks by putting them onto you, and charging you thousands for that.
A high trust society doesn't cause a monopoly to become efficient. A society where everyone is thinking of the common good is the one where individualism works, because then you have no need for a giant bureaucracy trying to coerce everyone into doing the right thing, since they would do that of their own accord.
But the disadvantage of bureaucratic authoritarianism is even larger in a low-trust society where everyone is in it for themselves, because then you can't trust the bureaucrats not to be corrupt and they're still sitting on a monopoly.
Which is to say, what you always want is a high trust society and what you never want is a monopolist.
Unless you are completely off the grid, you are getting power from a local monopoly. This is baked in. You get your water from one source, send your sewerage to one source, get your power from one source, etc. So then the question is how to make the monopoly well behaved and how to keep them that way.
It's more economically optimal to convince wealthy Vermonters to house the batteries by branding it as subsidized resilience than it is to buy and maintain substations?
If home owners are paying then it might be less efficient for the overall economy but better for the utility company. It is often easier to find a million people willing to spend a thousand dollars than finding one person willing to spend a billion.
There’s probably a significant element of consumer batteries being so good, so easy to setup, and so cheap to buy. That it actually ends up being more economical to take this approach, than build dedicated utility scale battery storage.
With consumer units, you can reasonably expect that they’ll operate with zero maintenance and zero direct supervision for a decade plus. If the cost of those units is low enough, that reduced operational burden starts looking very attractive, especially if you want to scale up your battery capacity across your network very quickly.
>With consumer units, you can reasonably expect that they’ll operate with zero maintenance and zero direct supervision for a decade plus
I highly doubt it. You can reasonably expect one hard drive to operate just fine for years, but data centers have to constantly replace failed drives, and that would still be true if they they put each one in a different building. It would just cost a lot more to do.
It's a 10 year lease agreement. You pay them, and when the 10 years is up you have to return the batteries. At no point does the customer own the batteries.
It's like leasing a car, except with a car lease you have the option to pay extra to buy it out at the end and take ownership; with this lease agreement you don't.
This is like leasing a car except that the dealership can show up with other customers to take "your" car for test drives or just to drive it around for any other reason whenever they want to, for however long they want to, and they won't pay you back for any of the gas they use. Basically turning your personal garage into their distributed showroom.
IIRC pre-covid when the program was quite new, customer could buy the batteries outright. Later on they added the lease option.
One of the issues with these is the limited storage capacity. While it is nice for short outages, there are sometimes multi-day events in the winter. I think the longest was in the late 90s from an ice storm and was over a week. If you have solar, less of an issue but not everyone does (though solar does have surprisingly good install base in Vermont).
I've not checked to see if GMP limits the install locations but do recall some states/munis trying to limit them to outside the home due to fire risk.
I hope that the system designers know what they are doing in Vermont.
The way an article is written doesn't explore the fact that at its core batteries are a 'consumer of energy' and not a producer like a power plant. You are losing electrons through heat losses and degradation in a bid to match demand with lowest cost supply.
Replacing generators with a battery make sense when the peak capacity is overbuilt, but it shouldn't be left unchecked.
The other challenge is that the customer's savings usually come not from the battery itself (the energy arbitrage) but from avoiding the usage charges from their distribution and transmission networks. Deploying batteries on grid without a plan pushes forward the grid death spiral where some users of the network feel like they no longer need to be connected as they can be self sufficient. That means that those that cannot be self sufficient have to share the same cost of infrastructure with less users on it. That is assuming that being self sufficient is economically viable and sufficiently reliable.
Those who think that home batteries and solar are 'cheap' should look into the true underlying costs. The per MWh cost of a home system is MUCH more expensive than a utility scale system. The savings are often just an arbitrage on a relatively high level usage-based pricing allocation of the transmission and distribution systems.
The network costs are mostly fixed by their nature - it's recovery of equipment cost and ongoing cost of maintenance activities. Cost per KWh can be different at different times because you need higher cost equipment that works during the time of high load. If there is no high load - the equipment is not needed and cost can be reduced. But this cannot happen overnight because the equipment is already there! Without forcing the networks into taking heavy losses - you have to allocate the costs to users,and unfortunately those that cannot afford to have these expensive home systems will end up paying the higher price. In effect your battery 'savings' are coming from people who cannot afford to have one.
I agree on all points. This is a short term cost saving measure at the expense of long term energy security. Batteries do help smooth the considerable volatility introduced by renewable generation, but unless they want a significant share of houses and industrial sites to have large batteries (which would cost FAR more than just keeping the power stations online), they still need base load generation.
Unless this is very carefully managed (and I do not think governments are generally capable enough), this will result in a lot of new problems. One will be major difficulties in developing new housing (or intensification) due to lack of electricity supply. Another will be insufficient supply during 99th percentile events in which home batteries alone will be insufficient to close the gap. Another will be distribution. Some neighbourhoods will have higher battery penetration than others, and this happens organically and without the permission of the grid companies. That's very difficult to plan around. Some areas are going to be secure, and others will not, unless the grid purposefully oversupplies, negating the potential cost savings.
Batteries are good at marginal demand smoothing, but I am very dubious about shutting down energy generation. Especially at this time. All analysis points to the reality that due to technology demands, we're facing an imminent power generation crunch. Prices are going to rise everywhere and demand will only increase.
There is no local "base load" generation to begin with. 73% of power in VT is imports from out of state/country. Primarily from Hydro-Quebec.
- There are no coal plants left in New England at all.
- Most of VT doesn't have access to Natural Gas (the Burlington metro does, via a pipeline that is only served from Quebec, it is not connected to the US pipeline grid). There are no Natural Gas plants in the state.
- The nuclear plant closed over a decade ago.
- Actual in-state generation on a normal basis is a few biomass plants, some modest hydro on the rivers, and some scattered wind/solar.
- The power plants being "replaced" here, or at risk of being replaced, are some small and rarely used oil-fired peakers that run a few hours a year currently and have nameplate capacity in total of <200MW even if they shut down all of them.
- Transfer capacity to stressed regions (NY-ISO, PJM) is low so they can't really draw that much off the region's grid (ISO-NE).
- Power prices are always some of the highest in the country, the region in general is known for regulation and disliking development - and VT even more so. Making it unlikely you see some sort of AI data center boom here or the like.
- The most realistic source of significant new demand in the state is probably electrification (heating, cooling, vehicles).
nit pick, but this isnt true at all. "Base load generation" refers to fixed capacity generators (coal, nukes) that run at 100%, matched to the lowest point of the demand curve overnight. This is an obsolete concept in a modern grid where batteries, wind, solar etc have destroyed that economic niche.
what you mean is likely "backup capacity". And yes heavily renewable grids will likely need some standin / backup generation for exceptional circumstances, for the foreseeable future. The economics and sizing of this backup is almost entirely unrelated to the economics and sizing of "base load generation". (for eg, there will never be a time when a diversified grid is at zero. The amount of backup needed is a function of how frequent these exceptional events are, the mix of your grid, and how much you're willing to pay backup generators to avoid load shedding in these situation)
Entirely agree. I think that this is fantastic technology and it will do wonders to avoid blackouts and deal with storm outages that people talked about. I just think that we need to have more care when it comes to energy.
Turning off plants is a lot easier than turning them back on. Especially when the rest of the world is building data centres and co-locatrd power and there are skill and equipment shortages.
These technologies bring a promise of clean renewable power which is great, but reality is that we haven't fully figured out how to do it reliably enough. I fear that we will get to a stage when old conventional plants are shut down, and we still haven't fully figured out the replacement. It will be a long period of unreliable and expensive power which will undermine entire economies.
The article does not make a big enough deal of another saving for the utility - it means that when snow takes out lines, they have more time to deal with the problems before customers start complaining. That can be quite significant if the utility can wait 12 hours for storms to pass, then fixing things becomes significantly easier.
I'm not sure how much of a benefit this is. Many/most houses/commercial sites won't have batteries (or at list some significant minority). They'll still complain. Power companies will still have a duty to restore power ASAP for health and safety reasons. Either way, they'll only repair the lines when it's safe to do so, and they'll continue doing that.
In Sweden we solved this by putting most power lines under ground and Sweden has the same population density and is larger. Power outages during storms is a thing of the past in most of Sweden.
Not saying this option would be better, we started this project way before batteries was a realistic option.
When coupled with solar, batteries are absolutely a net producer of energy. Around the clock too, as it allows solar generated at low-demand times to be redeployed when needed most.
That could be true, but I think important to clarify
- how big is the solar array and how big is the battery?
- what does the consumption look like
- is your battery big enough to help navigate through a week of cloud cover in winter?
- do you live somewhere with great solar resource
I don't understand comments like this. This isn't theoretical. This already exists in reality. It is reducing demand at peak times. It is preventing outages in rural areas during/after storms. It is so successful they are closing down power plants. I'm guessing you don't like solar/batteries for some reason? I don't know. This comment confuses me.
>More than 5,500 people in Vermont have similar home battery systems.
This is _literally_ a rounding error. It's less than 1% of Vermont.
So it's your comment that's truly baffling, though I'm sure others would appreciate if you posted your own source. There's certainly no power plant getting shut down because 5,500 customers have batteries, but again I'd love to be proven wrong.
Parent was just spreading a lot of fud, half-truths, and "yeah, maybe if you squint and force an exotic framing"... they're trying to convince you to throw the baby out with the bathwater, don't lose sleep about it.
I tried to signup for this program but the building code gets in the way. You need 3' from both edges of the battery to a window or door. I don't have a wall with 8-9' between windows. The alternative is to build a fire proof room in your house which takes up a lot of space. Ultimately it was not worth it even with all the financial incentives. The rules might seem innocuous but they're a dealbreaker. It's far easier to get a propane or diesel generator installed.
Generators are generally used outside. There are some rated for use inside, but they also have strict regulations on how that is done. (there are also some used inside but they will kill someone soon)
Maybe where you live, but where I live the temperature outside is bad for batteries.
Though what is "inside" is debatable. My car can sit outside because it has the batteries in a case that is climate controlled when needed, and so the batteries count as inside even though they are in a car that is outside.
I would be much more nervous about a 13+ kWh battery than a natural gas generator.
The generator is generally only risky when in operation. For natural gas units, a normally-closed solenoid keeps the gas off unless the controller actively commands it. A battery is constantly in a state of non zero fire risk when charged.
We have this in CA. I have Tesla batteries and they promote wanting me to enroll my batteries into a larger grid so their capacity can be used during higher load events.
I thought it was a novel idea when I heard about it.
> Tesla Electric customers report making as much as $150 a day
Only on peak demand days, of which there are only a handful every year.
I have Enphase batteries enrolled in an equivalent program, so I've tracked how much I make. Definitely not enough to make much of a dent in the payoff time for the batteries. But a nice perk nonetheless.
It seems like an unreservedly good thing if people with home batteries can help prevent brownouts and reduce prices for everyone else. Also, I believe the $150/day figure was during a rare heatwave event when prices had surged to 100x their typical value ($5/kWh). It’s like any other investment where you outlay cash upfront and hope to make it back over time, whether via reduced costs for your own electricity usage or selling it back to the grid when doing so is profitable.
And when the power lines fall down in rural areas, how will people heat and power their homes? I guess they could buy some batteries, but then they'd sit idle most of the time. Maybe they could find some other profitable use and share the capital cost?
> The people buying the batteries and the government's capital.
The former should be allowed to make their own decisions. I agree that the latter should probably be kept out of this: government is usually not very good at making these decisions. But alas, in many places they play a huge role in the electricity supply and distribution.
> The former should be allowed to make their own decisions.
Yes, but that's how we arrive to local economical maxima that are much, much closer to the global minimum that to the global maximum. The personal decisions aggregate, after all.
People are buying the batteries with their OWN capital, not Govts capital.
You say Govt capital which only benefits private utlities and ALSO say govt/utility should to build out the storage. Not sure what you are trying to say. You sound pretty confused.
In a lot of places the power companies are government owned and the private companies get massive amounts of captial from the government for buildouts.
Be more explicit. What is wrong with this? It's not all the time, it's only in times of extreme need.
Variable pricing like this enables all sorts of cost saving technologies that bring down the cost of the grid and generating power for everyone, by spending a lot for a very short time, instead of building tons of extra large assets that sit mostly idle.
If somebody is providing a service that operates on the whole sale market, they deserve to get paid like all the other generators that are helping to keep the grid running in these times of need.
for single individuals to earn as much as (i assume US$) 150 a day means that the grid is horrendously unbalanced.
hell if I emptied my 30kw into the grid in my state/country at the most expensive time I'd earn AU$21.00
to earn US$150 means either HUGE battery capacity (and transmission capacity) or utterly rediculous power pricing... both mean really lousy power supply and grid design.
I'm all for indipendance but the reality is we live in communities and count on the collective to rise us all up together.
that sort of profit is a clear warning sign of a broken community.
It depends a lot on the market, but before there were lots of batteries this was extremely typical in the Australian grid. You probably just weren't exposed to it as a consumer! Massive price fluctuations were the impetus for one of the first large scale grid batteries in Australia, and the batteries worked really well to solve it. It doesn't happen often, and nobody is getting paid $150 every day for their home battery. It's just for the extreme events.
As more and more batteries are deployed the price swings will decrease.
It's not a "broken community" it's just end consumers being able to help out in times of great grid need and getting compensated fairly for it.
It's more efficient for the grid to be very unbalanced every once in a while, rather than building so much it never happens.
And it's not a sign of a broken community. Those batteries aren't making all that much money on a per-year basis. And the earlier batteries into the system are going to make the most money. The more batteries that get built the smaller the profits will be and the better the entire grid will be.
California rate payers are being forced to essentially pay for fire insurance for CA residents who live in tinderbox areas, by way of PG&E rates, and burying lines that serve widely dispersed populations. That's the big difference. The vast majority of US residents have much lower utility rates.
It is actually a pretty great way to address marginal demand spikes without overbuilding generation capacity. With the fringe bonus of local protection from short outages.
I like the idea of a home battery systems. I live in a place with frequent winter storms and also hurricanes.
Grid storage large containerized batteries is a great idea too. There's even a local company (Aspin-Kemp) that makes them and also marine hybrid boats. The electric company here is a dinosaur wanting gas turbines and no interest in renewable energy just profits for shareholders. They even got caught with their pants down after a hurricane trees fell on power lines due to no tree maintenance for 40 years.
One issue with large battery storage is fires. Where I live is small and island with small towns the biggest city is at best 50,000. The next smallest city of about 15,000 uses grid storage batteries one of which recently caught fire and burned for a week. It's in a small town so the toxic smoke was a big problem. It would be very bad for a home battery system to ignite that's likely why my city does not allow home batteries inside homes.
A new method to douse battery fires needs to be developed. A week long fire and toxic smoke is very stressful.
If a home had a detached garage or a storage shed that would be a better area. Some of the newer model batteries can be outside in winter cold and snow on its own base like a stand-by generator would be.
I like the idea of a backup system or a system to offset high rates by storing power on off-peak times. Even if you don't have solar storing power from the grid at low demand times at night then use power from the battery at high energy cost times during the day.
Whatever way it's installed it's still a good idea to have an emergency plan or at the very least assume the worst and place the device away from the home.
I think there's suppose to be a feel good in here, but it feels like another race to the bottom. Power companies dont invest their profits they take them and then when the grid becomes unreliable put it on the customers with interesting excuses and eco-fashionable handouts to help the pill go down.
A bunch of people are commenting that this could lead to grid-death spiral where people opt out of the grid because they can just use solar + batteries. Maybe, but I doubt in Vermont. Vermont is really hard for solar because of tree cover and clouds (according to my conversations with a solar installer). Secondly, in this setup you have buy your own power plant (solar + batteries), which likely for most folks, is a pretty big expense. Green Mountain power subsidizing the cost of buying the Tesla power walls is a big deal for me because I use this setup for a cabin / second home and want to keep my costs relatively low. I can't do solar because I on the side of a mountain and lots of trees.
I love this. It’s basically an edge cache for power, with an enormous amount of side benefits - smooths out solar power, smooths out the duck curve, and allows the grid to size closer to the average load and absorb the spikes at the edge, instead of cascading into the core.
There was an article earlier about the distribution challenges that come from large workload fluxes, too - tl;dr is the transmission lines get less efficient under higher load, so smoothing out the demand curve to the end user also raises the efficiency of the entire grid.
And as someone points out below - the proliferation of EVs also helps this, because they can act as a “deep” reservoir so the local residential batteries can be much smaller - more buffers than something expected to run the house for more than a couple hours, so that makes the whole setup even cheaper, depending on when and where the EVs are getting charged.
And with the way that grid costs are coming to dominate electricity costs, these sorts of peak shaving technologies will be huge cost savers in the future.
This comment needs to be higher than all the "but storage is not generation!!" fud in here. Didn't realize how astroturfy hn had become. "edge cache for power" is the true spirit of what this is about
In my experience as a VT homeowner we have relatively frequent short outages. It's pretty rural and the weather is brutal. I think the grid doesn't have as much redundancy as denser areas. We had one 3 day outage 2 years ago in the middle of winter which got quite dangerous, but otherwise I haven't had anything more than a few hours.
Also we have propane heat - but I need electricity for the blower and control board. So the electric consumption is pretty minimal, but it is critical.
Assuming they set up the house to island, which depends a lot on the install. Otherwise live power from a house in an outage is a big risk to those working on solving the outage.
You also need to take into account the fact that VPP systems like this stabilize the grid by flattening the peaks and troughs, and reduce the average length of outages.
Most are hours but there are enough that are a day or more that it is a valid consideration. As to when, honestly I think there are more not snow related. Long stretches of wet (or floods) and high winds not a good mix.
I live just over the border in Massachusetts and we have something similar, called ConnectedSolutions. It is essentially the same kind of program except that the benefit is a 0% loan on the battery purchase. I have a 15kW battery that allows me to power the entire house overnight without drawing from the grid. When the power company wants to draw from my battery, they send me a notification through my battery’s app. I can opt out some fixed number of times, too. And, just as when my solar runs net negative, the power company pays me (in bill credits) whenever the virtual power plant draws power.
The only drawback, really, is that sometimes you _want_ the charge in the battery for yourself. If you take out a loan with a ConnectedSolutions clause (e.g., a MassSave loan), you are obligated to make your home battery available as a VPP under the terms of the loan.
Fortunately, one of the valid reasons for opting out from a "VPP event" (which is what my battery mfgr's app calls it) is a coming storm. In fact, in my system a "storm hedge" (where the battery tops itself up before a storm) trumps a VPP event, so for all practical purposes, there is little inconvenience. So there aren't really any drawbacks. And when you are done paying your loan you can either stay enrolled in ConnectedSolutions or not.
I say go for it. A 0% loan is great, and it was the deciding factor for us to buy the battery. Honestly, I wish I had bought a bigger battery! 15kWh is good for an evening, but not quite enough if the following day is rainy.
I bought a FranklinWH, both for technical reasons and because I could not in good conscience purchase a Tesla battery. I like the FranklinWH. However, I discovered that it is extremely chatty with a large number of hosts located in China. Most of the hosts it chats with are hardcoded IP addresses. This worries me a bit, not for xenophobic reasons, but because it strikes me as brittle. That said, I did end up putting the device on its own (firewalled-off) subnet. Although the app is kind of opaque, it works fine, and I mostly get the information I want via HomeAssistant, which has a FranklinWH plugin. I'm not sure if I would buy it again but it gets the job done.
My other equipment is mostly SolarEdge, which is excellent and well-behaved. SolarEdge now has batteries too-- I would probably look into them were I to buy a battery again.
A couple things to note. If you get a battery do not put it near your house. Generally, energy storage has a good safety record, but if they do experience thermal runaway, the fire effectively cannot be extinguished until all the fuel is consumed. Mine is 75' from my house because I have a solar groundmount array. Second, my solar installer initially set everything up using wifi, including a high-gain antenna because the array was so far from my house. I pointed out that I had an ethernet switch in my basement, so they ran hardwired networking through the power conduit to my house. Much more stable. Just ask for ethernet upfront if you can.
Except they're not replacing power plants at all, they're adding batteries to the grid to store and distribute power. After all, something has to charge the batteries.
>The US now has over 40GW of virtual power plant capacity, according to internal analysis by Wood Mackenzie. It's still relatively small compared to the roughly 600GW of natural gas and 200GW of coal, but a total of 160GW of capacity could be unlocked by 2030, according to a 2025 US Department of Energy report – equal to some 20% of the country's expected peak energy demand.
>Through GMP's programme, its virtual power plant has quietly become Vermont's biggest source of power. Now, the state is testing how far this "hidden" form of power can go.
Does anybody at the BBC actually understand what batteries are, and why they cannot possibly compete with power plants!?!?
> Does anybody at the BBC actually understand what batteries are, and why they cannot possibly compete with power plants!?!?
VPPs displace more expensive generation capacity at the margin. Because your marginal loads are for relatively short durations. It's actually quite smart, especially if you can get end consumers to subsidize it.
Is that a local question for Vermont, a nation question for the US, or a global question?
If the question is global, then yes, there are, although as renewable energy has increased globally so has the need for peaker plants to handle the variance in the grid, thus plants that historically has only been used for seasonal variance are now used all year round to handle weather variance. An example of that is the oil power plant in south of Sweden.
I think what he was saying is that with a peaker plant you have an extra source of power. So if you have a low wind/low irradiance period - you can rely on peaker to provide more power, but by this stage batteries are long gone.
What do you mean? These numbers provide great guidance so that people can understand the size of the battery discharge, and what they could replace.
Batteries do indeed compete with power plants, every day of every moment they are on the grid. They are also consumers from power plants, they go both ways.
Power isn't a particularly helpful metric here, energy is. Power doesn't tell you anything about how long the batteries will last, it only tells you how quickly they can drain. Also there's a limit to how much power you can draw through residential lines so regardless of whether or not batteries can deliver power on the same order of magnitude as a coal-fired plant, it's highly dubious that these specific batteries can do that.
>Batteries do indeed compete with power plants, every day of every moment they are on the grid. They are also consumers from power plants, they go both ways.
Hey don't tell me that, tell the BBC. They're the ones who wrote an entire article about "replacing power plants with home batteries".
They literally did replace power plants with these batteries though. From the article: “ GMP similarly used to rely on oil, diesel and natural gas peaker plants to meet peak demand. Now the company's virtual power plant has effectively replaced them, says McClure. "We've been slowly able to decommission those as they've become end-of-life," she says.”
I don't think the BBC is confused here at all. Batteries do indeed replace power plants. They are already actively replacing gas peaker plants all over. In California, batteries they are dramatically reducing regular, non-peaker, gas turbine generation, by outcompeting them on the grid.
> Also there's a limit to how much power you can draw through residential lines so regardless of whether or not batteries can deliver power on the same order of magnitude as a coal-fired plant, it's highly dubious that these specific batteries can do that.
These specific batteries, on the other ends of residential lines, indeed do push power back on the grid in aggregate enough to replace coal power plants. There's nothing special about a point generator on the grid versus the aggregate action of thousands of batteries on the other side of the distribution stations. In fact that's what's so amazing about batteries versus large thermal generators: thermal generators are large because if they get super inefficient when they're not large. Nobody is installing a small coal generator at their home to run daily, and even small diesel generators are hugely inefficient. But batteries are so useful that even accounting for the extra expense of large numbers of custom installs, they reduce grid demand enough to make a ton of financial.
And power is indeed the most important metric when it comes to the grid. It's how everything is run, how individual grid assets are dispatched, because power needs to be balanced at every moment. Somebody could throw an asset on the grid that only dispatched for 15 minutes (or whatever the minimum bid time is), and it would still be described primarily by power. Capacity decisions may be made in kW-month or whatever unit, but you can run a grid on a pure energy market without any capacity market at all, as ERCOT shows.
I agree with how power is a bad way to measure batteries a lot of the time (though if you assume they last 4 hours you shouldn't be too far off).
But I don't think the residential line limits are too bad. A house that's sending out power takes its load off the grid and can also power multiple other houses without any lines being overloaded. And if an area has a high enough battery:house ratio, the full megawatt capacity of powering those houses but flowing the other way is a ton of power. (If the equipment can handle power flowing both ways.)
I wonder if increased reliance on VPPs increases the difficulty of a black start. Especially since these things are internet controlled, I can't help but feel like there's a bit of a circular dependency. Can't coordinate the VPP without internet, can't have internet without power, can we black start without coordinating the VPP?
You can't do a black start from the lowest potential part of the grid anyways. Synchronization isn't the hardest part. You could solve this with GPS and cellular telecommunications. Fault current handling is where things fall apart. You have to start the grid from the top. Fault current has to flow in the right direction or none of the existing equipment will function correctly.
The power walls can help to stabilize islands once they're back online, but they can't meaningfully participate in the initial phase.
That's an interesting question. I would think that it depends on what generation the batteries are replacing. As far as I know VPPs are relying on domestic inverters that do not have grid forming functionality required for black start. So you essentially have less plant capable of black start which I would think makes your black start capability worse.
I couldn't read the article because of paywall issues. I have a Tesla powerwall that I pay $50 / month to lease from green mountain power. I have piece of mind for power in a rural area - the power company get peaker benefits. Seems like a great deal. I wish we had this in Massachusetts. Mad river valley area.
The way an electricity utility works, you need power plants (or to buy power from someone with power plants), transmission lines and some form of last mile delivery. You have substations and other infrastructure too. That infrastructure has ongoing maintenance costs but also capex to build it in the first place.
So your per kWh price is the sum of the electricity cost, the maintenance cost and the amortized capex plus some profit.
Utilities are heavy regulated but only the electricity cost tends to be highly regulated. Any maintenance or capex costs can be passed on directly to the consumer. Private equity has realized this. Data centers have realized this where they can negotiate a lower electricity rate and the build out for multi-gigawatt transmission and power generation can be passed on to consumers. This has gotten creative enough that people in unrelated states end up paying more because of upgrades required for shared infrastructure for interstate utility compacts.
The obvious endpoint for all this is for users to eventually opt out. Disconnect from the grid and use totally renewable energy plus batteries. Generally in any urban environment you can't avoid the monthly connection cost even if you use no power. The city will declare your house unlivable. I can see this changing in the coming years with soaring prices that basically go to share buybacks and bonuses for private utilities.
But what if the connection to the grid drops significantly shifting maintenance costs to the rest?
I think the future is going to move away from large connected grids towards self-sufficiency and smaller localized grids, ideally municipally owned. But you can't gradually move from a large grid to smaller grids like this because of the problems of who pays for the grid in between.
I think you are spot on. The grid death spiral. Unless you can have enough generation co-locatrd with consumption you need the grid and the utility scale plants. In the densely populated areas you simply cannot have enough generation within the same footprint as the demand with existing tech.
First, the 110 MW is wrong. It’s 53 MW of home batteries. Not that its the most important detail in this situation.
What is important in this context: Vermont already depends heavily on imported electricity and hydropower. The EIA says 73% of Vermont’s electricity is imported. Can we please acknowledge the stupidity of thinking you can replace generation with storage?
I could not find confirmation of how much battery capacity is actually available, but some simple math, based on an average load of 621 MW for Vermont, results in home batteries currently covering 14 minutes per day of power, meaning about 1% of daily needs.
I also found the real source of electricity used in Vermont: Hydro-Québec’s 28 large reservoirs contain about 176 million MWh of stored energy. This means the entirety of the stored energy at home is literally one million times less than what actual power plants can provide.
So, yeah, don’t turn off those power plants just yet, thinking you have “replaced them with home battery storage.”
And this is from someone who loves the idea of home battery storage and actually has my own small setup. Something being aspirational does not mean one should just spew misleading stuff like this.
> Can we please acknowledge the stupidity of thinking you can replace generation with storage?
Electricity consumption is not constant, just like generation isn't constant with some sources. You can certainly replace a number of peaker plants, e.g. gas turbines, with storage and reduce costs by a lot.
Yeah, peak shaving is a real thing, and it's actually a no-brainer, I think. I just got a bit annoyed and carried away because the article did not make clear how large a challenge it is to actually disconnect from the grid and stop relying on power plants.
The reason is that I have been dabbling with off-grid gear for fun. Nothing major, just a solar power station and a couple of solar panels. And here in Norway, you really get respect for how hard it is to get energy during the winter when there's no wind and no sun. Even if I had 100 kWh of battery storage and 20 kW of rated solar panel capacity, I would be dead in the water, at least for the entirety of December and January. The only viable solution for going full off-grid in Norway is a backup generator. You could get by with wind, maybe if you live in a predictable windy area and you have a large battery bank.
Since it's so cold and darker during the winter, I have always dreamed of someone making a really good Stirling engine for generating electricity. But there are way too few people living as far north as us, so there's really no demand. You don't have to go further south than Germany, and solar is fully viable on its own, even during the winter. And the entirety of the United States, with the exception of Alaska, is completely self-sustainable per household with just solar. But off-gridding one's own home is suffering the March of Nines problem, whereby it's exponentially more expensive to be grid-independent 99.99% of the time, and so forth.
I'm rambling now. Suffice it to say that I stand by the fact that the article is misleading, though the goal of off-gridding and getting as much solar and in-house storage as possible is something I wholeheartedly agree with. I don't like it when people don't communicate how large a challenge it is.
Wispr Flow is a dangerous tool It seems..... it makes it way too easy to write a lot of text.
We are participants in this program. It's awesome.
For context, we are 3/4 miles from a paved road, and on our dirt road there are 6 homes. Like many houses in Vermont, we have a well instead of municipal water no power -> no water. Our house also came with a pellet stove that requires power in order to operate[0]. No power -> no heat. Ditto the propane boiler that runs domestic hot water and the baseboard radiators. Cell service is pretty sparse, and depending on your carrier you are wholly or mostly dependent on WiFi calling to report outages. Bit of a circular dependency there. There are lots of homes in VT like this.
The batteries are totally seamless. The only real indication that we're on battery is that anything without a crystal oscillator in it runs fast until the batteries are depleted enough that they could accept a charge from the solar panels we don't (yet) have[1]. The controller raises the line frequency to 66Hz when disconnected from the grid to let the inverters for the solar panels know that it can't/won't accept charge.
In practice this all plays out really well. We haven't yet had a winter outage that went on for more than a day since we moved. Last summer, however, we stained our home. The power comes in on the gable end, and we had Green Mountain Power disconnect it so we could sand and spray that part of the house without having live 240v power to work around on scaffolding 25' in the air. Running minimal lights, the fridge, the internet, the well pump, and either a couple of 5" sanders or a 60 gallon 240v compressor (for the spray gun), we got 4 days worth of uptime from the two battery packs. It was incredible.
The only downside to all of this is that the installation allowance wasn't enough to split my shop off from the backed-up panel[2]. I heat it with a heat pump (because insurance insurance companies get understandably twitchy about fuel-burning appliances in a wood shop). It draws a substantial amount of power when it's cold out, and if we lose power overnight and don't get awakened by the app notification, it's going to suck down a fair bit of power before the morning. The obvious workaround is to shut down the heat pump if there's bad weather in the forecast.
This probably isn't as much of a fringe case as it sounds. Anyone who heats with a heat pump is going to have to choose between not having heat or forgoing a lot of uptime.
[0] We will eventually replace it with a plain wood stove for resilience in the face of power outages.
[1] The ridge line of both the house and the shop runs north/south, so not ideal. The house has a dormer that precludes putting panels on half the roof, and skylights that preclude putting panels on another quarter of it. The shop needs to be re-roofed with metal and we need to have a couple of trees taken down before we can entertain putting panels on that roof. There have been higher priority projects over the last couple of years.
As a consumer, would you want the extra usage on your battery? Those extra cycles have to cause some additional degradation to the system, but I do not know how much.
> As a consumer, would you want the extra usage on your battery?
I feel like this is likely going to be a non-issue in practice. Because these batteries are rated to last at least 10 years either way. And by that time, the cost of replacement will be dramatically cheaper.
They're rated to last that long under a full charge-discharge cycle per day. You won't be using them more than that unless you're doing something really crazy.
Net metering rates are pretty poor, so I would guess not much outside of extreme grid instability. Although, you then might want to selfishly hoard the juice for yourself.
Depends on the nature of the agreement and the need for energy. In a load shedding event, the power company may want to cut useless residential consumers so as to prioritize hospitals. From a maximal good perspective, it is better that the hospital is running than I get to run my AC when the grid is straining.
Yes, but last I checked the bidi chargers were proprietary - tied to vehicle manufacturer - which is a huge disincentive. I don't want my home's battery connector locked into a vehicle brand/manufacturer.
Yes, thanks for the clarification. It goes without saying nobody can take energy from anyone without their permission. The manufacturers should build all cars with V2G feature, then people have the choice to participate in the energy ecosystem.
In a hypothetical future where every single car participated, you probably wouldn't need to dedicate more than a few % capacity to still make an absolutely massive VPP
That infrastructure fee isn't going to go down despite your new capex (and opex) costs. Congratulations, everyone just got duped.
Sure it starts out covering edge cases but the more they realise they can shift a burden - and cost - to homeowners, it'll spread. I don't want grid infrastructure in my home personally
What happened to economies of scale?
It's more important for shareholders to increase profits than to actually invest in infrastructure.
That is exactly right! Put the batteries where the cost of strain is the highest.
My belief is that this is ideologically/politically motivated. If you put the batteries next to network equipment it will not have the same immediate saving effect/user experience as the battery at home.
Battery at home gets a response of someone being happy about getting apiece of hardware, saving money and being renewable!
Vermont gets occasional ice storms or heavy snow that brings down trees on the power lines, so having a battery in your house can be pretty useful.
I'm a bit nostalgic for the nights when we'd break out the kerosene lanterns. But I concede that this might be more practical and a bit safer (a lot of VT houses are tinder boxes and good luck getting a good fire response in an ice storm).
Base power is doing something similar in Texas. AFAICT, they take a loss on the equipment, charge the batteries when electricity prices are cheap, then sell power out of the batteries when prices are high and keep the difference. The homeowner enjoys only most likely having backup power.
I mean, the electricity still has to be generated. That still costs money. This whole thing only works as long as there is someone willing to buy at the high prices and off peak demand stays low enough to keep prices cheap. Eventually there’s no more road to kick this can down.
> Eventually there’s no more road to kick this can down.
What do you mean? The opportunity for energy arbitrage will go away if energy prices are constant. Right now they aren’t, and I don’t really see how they would become constant based on the physics of producing and consuming energy.
Okay, well, that’s clever for now. The real arbitrage base is pulling is getting in while there’s capital to be raised for it and money to be extracted from the market, before competitors emerge and the incumbents respond and everyone realizes the play all along was to build an enormous battery plant without the expenses of land and compliance and negotiating with producers and carriers. They’re in the buying low phase now.
They’ll sell high when PE buys the company and pulls a Broadcom on all the existing customers, who will abandon the equipment after ten years go back to installing Tri-fuel generators while Centerpoint deals B2B with serious battery plant operators instead of B2C with annoying consumers
Customers running batteries they don’t own to store energy they can’t use for a company that won’t share profits is not the future.
Vermont’s project might be more viable, they’re a little better able to see beyond a spreadsheet up there. California will regulate it into unsustainable price territory. In the meantime finbros in Texas will make a killing having Claude build badass dashboards to show how much they make off bored suburbanites stuck on a grid built and operated as cheaply as possible to take as much money as they can before the useless state government is run out on a rail or finally eats the last bite of its own ass
> I always wonder what happens when these things catch fire
If you're hoping someone will chime in to tell you they have magic firefighting foam inside them or something, I regret to inform you that what happens if it catches fire is exactly what one might naively expect from large lithium batteries.
Newer LiFePo4 (Lithium Iron Phosphate) batteries don't have the fire issues that the previous Lithium Ion generation did. They are a bit more expensive and heavier, but they are superior in every other way (safety, lifespan, max charge cycles).
Which version do you have? I believe they switched to LFP for V3, which should pose significantly less fire risk than the NMC chemistry they were using for V2 and before
The headline says that the batteries are powering the homes, which is absolutely and technically correct use of "powering".
Maybe you saw "generating"? It may interest you to know that batteries output is counted among "generation" by the EIA and nearly all grid documents I know about, and is also technically correct.
Natural gas is merely stored solar energy too, if it the ideas of batteries "generating" anything rubs you the wrong way.
I find it funny the article doesn’t mention Tesla once given these are all Tesla batteries and the picture is of a lady standing next to one. Great journalism, not biased or trying to steer the narrative at all.
This article is all over the place, but the principle is pretty simple - rather than adding more generation for peak usage times, batteries store energy generated off peak and smooth out the macro usage trends.
Our local utility in NC has a program where they'll pay you ~$50/battery/month to enroll in their virtual power plant program. In exchange, they can take control of your battery up to 36 times per year for a period of a couple hours. Summer events are typically early evening during peak air conditioning times. Winter events are typically early morning during peak heating times.
In practice this means one of two things:
* They make your battery charge to full capacity in advance of the event, and then you run your home off the battery and don't take any power from the grid during that time * Sometimes you'll also return power to the grid beyond that used by your house - they pay you the contracted rate for the power you deliver
We've paired our batteries with solar panels, so generally we have a full charge going into the summer VPP events. We have gas heat, but I expect we'll pay for at least some grid energy to charge batteries during the winter events. Regardless, it's been a good program for us - even without solar, we would not pay for any more power than we used, and the monthly rebate from the utility makes the economics of the system a lot more favorable, especially here in the land of relatively cheap coal power.
Ideally for people with a battery they would take charge to manage your battery between 50%-80% full, paying you for anything you send to the grid. 36x a year means major peak events only (one assumes with a limit of 36 they will try to be under that just in case the last day of the year has a problem). However a 50-80% policy is nice to batteries and means they can use it for even tiny local peak events. Ideally there would be enough home batteries that between all the renewables (Parts of NC are part of the TVA with plenty of hydro) they go months between using a fossil fuel plant.
I would assume they do not use every enrolled home's 36 allotment on the same 36 days.
What happens if you have a local power outage but they have drained your battery down?
Not the OP, but I'm on the same program in NC. You can set a minimum level to keep your battery that will cover at least short power outages (mine is set to 20%). You can also decline to participate with a limited number of VPP events a year.
My utility doesn't have a program quite like this, but they do have a peak power rate that incentivizes similar behavior. I have our system configured to charge up to 90% at 12pm, and then consume no grid power until 7pm (peak rate is 1-7pm), or if the battery gets down to 35%.
I also have it configured to charge to 100% if there are any weather watches or warnings. That overrides the time-of-use configuration.
We do also have a generator that I can hook up if the batteries get too low. We have enough battery to get us through the night, but we don't have enough solar to keep up in an outage during the darker months, or if we want to run the A/C.
How 'bout accepting their $50/battery/month deal for only some of your batteries?
Batteries don’t replace a generator.
What is a generator if not a battery that charges with fossil fuels? As long as the battery has enough energy to cover the outage the end result is the same.
Combine it with rooftop solar to get the equivalent of free fuel for your generator every time the sun shines.
> As long as the battery has enough energy to cover the outage the end result is the same.
That is the key—having enough battery to cover an extended outage is very expensive.
My generator can run on natural gas, which is piped to our house and only had one outage in the fourteen years we've lived there (when the gas company replaced lines as part of preventative maintenance). So effectively, we have a redundant electricity source coming into the house. If that was also down, I could also run it on propane or gasoline.
That being said, if I had to pick batteries _or_ a generator, I'd prioritize batteries. We have both, and the batteries cover the majority of outages, while also providing other benefits.
A battery will replace your generator and you are too late to stop it.
They can, depending on storage and outage duration you plan on mitigating. For example, a friend in ComEd's Northern Illinois service territory has quite a bit of rooftop solar. They subscribed to Base Power [1], who came and installed battery storage on site. Base Power became their power provider, which is a few cents/kwh cheaper than ComEd, because they charge the batteries at night when demand is low and Constellation Energy's nuclear fleet is still pumping out power (Illinois has the largest merchant nuclear fleet in the US [2]). Their daily solar generation is sufficient that if utility power fails, daily solar generation is sufficient (with batteries for coupling to enable continued solar production when utility sync is lost) to not need a fossil generator; the battery will carry them from sunset to sunrise until the solar panels are producing again during daylight hours. "What is your risk model?"
If you cannot install residential solar, don't have enough solar, or have to defend against outages lasting for days or weeks, having the infra available to support an exterior fossil generator is certainly something to consider (main load center transfer switch, receptacle on structure exterior for genset supply to the load center or a subpanel of critical loads).
[1] https://www.basepowercompany.com/ (no affiliation, I just like batteries!)
[2] https://nuclearbarbarian.github.io/IL-NLIC/index.html
> They make your battery charge to full capacity in advance of the event..
> We've paired our batteries with solar panels..
Does this imply that the scheme will charge your battery from the grid, and that you don't technically even need solar?
I've never considered that one might get a battery without solar, but I guess you might have some power needs that would make it worthwhile to draw on during cheap periods and drain at peak?
We're in the GMP program from TFA. We don't have solar (it's on the list of longer-term projects). GMP is using the batteries solely to time-shift the load by charging from the grid during periods of low demand and drawing during periods of high demand. It decreases their (and indirectly their customers') costs because peak-rate power is expensive to buy or generate.
Does GMP have a community solar program or something similar where you can group buy solar?
https://solarunitedneighbors.org/co-ops/ is a resource in this context, https://www.brightsaver.org/ for balcony solar (Balcony solar is legal in Vermont via https://legislature.vermont.gov/bill/status/2026/S.202).
(seems like it would make sense for GMP to deploy batteries everywhere commercially logical first wave, and then follow with distributed solar generation across their service territory: https://greenmountainpower.com/map/service-area/)
Solar is very popular in Australia, to the point that we have too much surplus during the day. So now we often have effectively free energy late morning to early afternoon. So while not common, some people here do get batteries despite having no solar, to store the excess from the grid for when it’s more expensive later.
Reading this is the first time in a long while that I've thought, "Man, I love this. Living in the future is awesome."
Correct, solar not needed. Depending on your battery capacity and usage patterns you could enroll in one of the plans that lets you pay cheaper rates off-peak to charge your batteries from the grid, and then power your house off the batteries during peak times. Some places this makes a lot of sense - the spread here (between off-peak, flat rate, and peak) is not favorable enough to make it interesting though, as far as I can tell.
I’m in a similar setup where I live in Australia. Our house has solar and battery — unlike the people in the FA, we purchased it directly ourselves, although with a significant government rebate.
Our battery is under automatic VPP control, but it’s not like it randomly starts exporting when we don’t want it to. When regional demand is high (hot days) or supply is low (no wind or cloudy), our battery might start exporting. But that’s a good thing for us, because our electricity is priced wholesale and changes every 5 minutes, and export rates are high in this situation. A couple of times there have been price spikes and we’ve made a few hundred dollars in under a hour. It’s a win-win for us (making money) and the grid (providing stability). To be fair, those spikes are rarer now than they were a year ago.
You can always control the battery if you want. Sometimes I’ll manually export even if prices aren’t high if I know I don’t need the power in my battery. Sometimes I’ll prevent export if I know I want to charge the car overnight from the battery. But mostly I let it do its thing.
From an investment perspective, the battery has been a no-brainer. Even without the windfalls from price spikes, being able to defer grid consumption to daylight hours (when wholesale prices are very cheap or even negative, i.e. we get paid to charge the car) puts the ROI in the 3-5 year range.
Without a VPP, I've estimated that it would take about 9 years for a battery to pay for itself in QLD. What VPP provider do you use?
Amber is my retailer, and it’s their SmartShift VPP system that controls the battery to minimize grid consumption and maximize export revenue. The battery/inverter system is SigEnergy.
It sounds like your regulatory environment has properly incentivized infrastructure.
Where I live in Canada, it's extremely unclear whether anyone is making their ROI on solar installations.
Orthogonal but related: where I live, homeowners might get charged negative prices at times for solar re-injected in the network. This doesn't make a ton of sense for me since you could just unplug the panels instead of being charged for the production! However, the electric company charges you retroactively (on a 15-min bucket) so you would need an accurate model to "beat them at their game". Negative electric prices in a country with a huge amount of solar/wind/hydro is surprising, since all of these production methods can stopped on demand (and even reversed in the case of some hydro setups).
This is the case for us, too. The reason is that whenever there is more supply than consumption on the grid the excess must be shed, and that costs the utility. Hence negative export prices to discourage supply to the grid.
Our battery/inverter system automatically curtails solar generation when our battery is full and export prices are negative, so this isn’t anything we need to think about. (Exception: I’ll charge the car to drain the battery overnight if I expect curtailment the next day. No point letting all that free sunshine go to waste!)
The negative price can either be from subsidized renewables that are passing some of that subsidy onto people who use the power (a good thing!) or remaining coal plants that can't flex fast enough and would rather pay than incur extra costs from flexing (which is good in that they are being effectively fined for lack of flexibility but bad in that they are inflexible and still generating dirty power while more flexible renewables curtail).
If clean energy is being curtailed increasing usage is a better response which negative prices also incentivize but in many jurisdictions they refuse to pass those price signals onto users because they'd rather waste clean energy so they can sell them dirty energy later.
In Australia it's not uncommon on moderate temperature sunny days for the wholesale price to enter the negatives. Lots of solar production, with minimal heating and cooling demands.
Many plans offer a 3 hour period where electricity is free to encourage shifting your load to that time. Which is amazing if you're able to charge an electric vehicle in that time, a standard single phase charger could provide 21kw/h in that 3 window all for free.
It's interesting that we're seeing situations now where we have excess energy, and can't think of a good use for it that doesn't just involve storage.
Kind of like a home energy dump that does something tangible, like bake a potato or something. You could come home in the afternoon and be rewarded with a reheated meat pie, or some chips that are automatically dumped into an air fryer.
You could also store that excess energy, and use that stored energy to bake a potato only when you want to, or something.
I've heard that aluminum smelting makes for a good "energy dump" and actually is almost more important to the economy at energy price aribtrage than as a source of aluminum. But Iceland and a few other places have already taken a lot of this market and maybe we already have as much aluminum smelting as we need.
Maybe I’m not picturing it correctly but wouldn’t a negative price mean more money in your wallet? Or are you saying that the set price is less than it costs to produce the energy on your side?
Neither. “negative prices at times for solar re-injected in the network” means that you have to pay if your solar setup sends power into the grid.
Conversely, at such times you can get paid to consume electricity.
This is a problem on Hawaii where the combination of an island power grid (can't sell it to the next grid over) and optimal conditions for solar.
They've added some grid scale batteries - https://www.asce.org/publications-and-news/civil-engineering...
> Situated on 8 acres of industrial land, the Kapolei Energy Storage project comprises 158 Tesla Megapack 2 XL lithium iron phosphate batteries, which are about the size of a shipping container. All told, the KES project provides 185 MW of total rated power capacity, or the largest possible instantaneous discharge, and 565 MWh of energy capacity, or the maximum amount of stored energy.
> The system can meet 17% of Oahu’s electricity demand for three hours at peak load or six hours at half load, Brandon Keefe, the executive chair of Plus Power — the company that developed the project — told USA Today. Plus Power “develops, owns, and operates standalone battery energy storage systems that provide capacity, energy, and ancillary services, enabling the rapid integration of renewable generation resources,” according to the company’s Jan. 11 news release announcing the start of operations at its KES facility.
There's also a practical.engineering episode on this: https://practical.engineering/blog/2024/3/18/how-the-hawaiia...
https://www.hawaiinewsnow.com/story/23689275/lawmakers-call-...
And today... https://www.hawaiianelectric.com/products-and-services/smart...
The amount of power rooftop solar in Hawaii is allowed to export to the grid is regulated.
> Customers enrolled in NEM Plus Limited Export are required to install a control device at the utility meter to limit the combined export capacity of the existing and additional generation to the capacity of the original NEM system. The battery must be programmed to 'load-following' mode so as not to export to the grid -- except when providing exports for grid services.
Seems like a good reason to get a battery.
https://www.latimes.com/world/la-xpm-2011-jun-14-la-na-adv-w...
> Lately though, electricity, not recreation, has become the big-ticket wind client in the Columbia Gorge. Wind turbines have sprung up all over the blustery hilltops in eastern Washington and Oregon, an area soon to become home to the largest wind farm in the world, developed for customers of Southern California Edison. Indeed, half the massive new wind power generated in the Pacific Northwest goes down the grid to California.
> For the last three weeks, however, many of the wind farms have been ordered to shut down their generation for several hours a day — victims of an unusual surplus of hydroelectric power that has confounded regional electricity operators and infuriated renewable energy advocates who have worked so hard to develop the region’s wind bonanza.
> The problem is an unexpected collision between two of the Northwest’s most treasured environmental assets, wind power and endangered salmon. Spring flows on the Columbia are so high that power system operators say they cannot dial back hydroelectric generators without harming the small juvenile fish now making their way down the river in their spring migration to the sea. With the turbines generating so much electricity, there is much less room on the grid for wind power.
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In some areas, hydro is coupled with environmental regulations. You can either use the water for power (doesn't mix with the air when doing so), or have it go over the spillway (substantial mix with the air).
The hydro plants, during periods of time when fish are swimming upstream are regulated on how much they can have go over the spillway - and so are forced to generate power... and potentially more power than the demand calls for, and so you've got negative rates.
More on this:
https://www.windpowermonthly.com/article/1133689/stoppage-co...
> BPA insists it can dump only a limited amount of water over the dams because excess spillage creates dangerous levels of nitrogen that are harmful to salmon and other fish. The curtailments may defy an order from the Federal Energy Regulatory Commission (Ferc), which ruled in December that BPA, as operator of 31 federal dams and much of the regional grid, cannot discriminate against wind power by forcing unilateral shutdowns. Several factors have changed since last year, but wind generators still stand to lose millions of dollars.
Another aspect of this is timing. Solar and wind have peak power at different times (and different times in relationship to demand).
https://www.forbes.com/sites/jamesconca/2014/01/18/wind-ener...
> But notice that the thermal generation (nuclear, gas and coal) does not vary much at all. It is the hydro component that has to constantly cycle up and down to adjust to the demand and to wind’s intermittent supply. This competition between two renewable sources means that the relatively carbon-free accruable hydro energy must be shed to take on the wind supply, with no net benefit in carbon emissions or energy cost.
> But constant cycling between 2,000 and 4,000 MW produces significant wear on the hydroelectric turbine gates.
> The following graph compares wind energy production and total demand (or load) for the first half of January 2014. Wind is weakly, but negatively, correlated with demand, meaning wind energy generally comes onto the grid when it’s not needed. Thus the constant need to ramp down hydro production to accommodate.
Demand curve is also known as the duck curve, because it kind of looks like a duck. https://en.wikipedia.org/wiki/Duck_curve
From 2017 Confronting the Duck Curve: How to Address Over-Generation of Solar Energy https://www.energy.gov/cmei/solar/articles/confronting-duck-...
... which brings us back to the article:
> Solar coupled with storage technologies could alleviate, and possibly eliminate, the risk of over-generation. Curtailment isn’t necessary when excess energy can be stored for use during peak electricity demand. SETO launched several projects in 2016 that pair researchers with utilities to examine how storage could make it easier for utilities to rely on solar energy to meet customer needs around the clock. This research will enable even more solar energy to be integrated into the grid, while tackling the obstacles utilities face when incorporating solar.
Though this will be something to look at for in the winter with "how does the house get heated?" https://www.maps.com/home-heating-fuels/ - This likely won't impact New England too much as that's primarily oil, but it's something to watch for. The "batteries with solar backup" would have more difficulty if there was increased demand for electric heating and reduced solar production.
> To be fair, those spikes are rarer now than they were a year ago.
Which, we should remember, is a good thing for society.
Absolutely. It’s amazing here how government incentives to install batteries have led to stabilization of the grid. Power outages are pretty much a thing of the past now.
How is the price system set up when re-injecting to the grid?
Do you get the full 5 minute spot price, or do they then charge you re-injection costs per kWh?
And are the grid-costs fixed yearly, or do they also charge you per kWh re-injected?
Here in Belgium, there's "a bit" of asymmetry: the price per kWh I pay from the grid is roughly 3 times of what I get when I inject. I also have a fixed cost per year to have the right to inject. I knew this before I installed solar and have a home battery, so it only happens during summer.
When I had my house in Belgium we had ours just before that change. Our meter (analogue) rolled back.
I know they were phasing that out, but I don't remember if it was phased out for everybody, even the ones grandfathered in?
2 things. - meter rolling backward: it's completely gone. You cannot refuse the replacement and they have ben replacing them since 2021.
- I was wrong: the asymmetry is a factor 6 iso a factor 3. :(
Distribution charges are per kwh and vary by the hour (more expensive in high-demand morning and evenings, lower during the day and at night). The spot price has to be high enough to exceed the distribution charges for net income on export.
Most of the time, distribution charges are higher than the spot wholesale prices for import and export.
Here's a better article:
https://electrek.co/2026/07/28/vermonts-largest-energy-sourc...
Seems like they supply each person with 2 Tesla powerwalls for the $55/month and get a reduction in their bills that depends on how much power they choose to share to the grid during power outages.
They've already closed down 2 peaker power plants because of this, so it doesn't seem to just be about handling power outages, but also handling fluctuating power usage instead of firing up extra power plants.
>They've already closed down 2 peaker power plants because of this, so it doesn't seem to just be about handling power outages, but also handling fluctuating power usage instead of firing up extra power plants.
Yes, that was a significant early argument I remember around the public benefits. The daily power spikes have always been a major challenge particularly when you don't have much commercial/industrial base. And even in the earliest period of the original 2000 home pilot they were surprised and pretty happy about how much load could be spread and the resulting savings. Note though that regulators were cautious and there was controversy around how well it'd actually work, you can find articles like this 2019 VT Digger one [0] from the era. Fortunately it did indeed work out, but easy to forget it was all pretty new at one point.
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0: https://vtdigger.org/2019/09/05/state-calls-for-investigatio...
I was thinking exactly about this when reading the article. The article writes about house owner benefits but it's the benefits of reduced peaks that are more likely to make providers wanting to do so. With this in place, power plants can take half an hour to increase their generation and top up the battery, instead of having to have faster plants round that caters to peaks.
We're in the program. The powerwalls don't share to the grid when there's an outage. We don't get a direct reduction in our bill for having them. Everyone on GMP gets better rates because GMP isn't buying power wholesale at peak rates or generating it with peaker plants.
Lithium is not the way to go for home batteries. As size/weight are not an issue for a basement or shed install, oldschool lead-acid are much cheaper and can be easily recycled once at end of life.
Those tesla wall packs will be a massive headache when they give up the ghost. Read the contract carefully. Who is responsable for end-of-life disposal? Where/how are they to be disposed of? Lead acids can be taken to any number of recycling centers, some will even pay you for them.
We're in the program. As written, it's a 10 year lease, and there's no option to buy-out the equipment at the end. We'll see if they offer that as an option as the end of the lease approaches in another 7 years. For now though, GMP is on the hook to come and get the equipment.
I would also suggest that size and weight are bigger concerns than you're giving credit to. They aren't assembling packs on-site from individual batteries. They're rolling in whole-ass packs in one swell foop. Getting them into basements isn't a small job[0]. Getting them back out will be even less fun for the crews.
Their total on-site install time was maybe 6 hours, and that included tying everything in to the existing system. Putting the hardware in place took maybe an hour of that time. If you want to go with heavier packs or more/larger packs, you're going to add to that a bit. And their doing this in people's finished homes. This isn't new build where they can have a couple of big dudes wrangling packs around without a care in the world for furniture and finished surfaces. The ergonomics of smaller packs matter.
[0] They used a two-wheel dolly with a hydraulic disc brake (bicycle hardware) to get them down our basement stairs.
If the utility owns the packs, part of me wonders why not build out battery stations around substations the utility already owns, instead of managing many small batteries in individual houses.
Seems like the former would have some development costs but ultimately be cheaper to manage
Doing it that way they couldn't charge a lease to the homeowners. By leasing the batteries to the homeowners they're offsetting some of the cost through that lease, but also the selling point for the homeowner is they (presumably) now have a backup in case of a full outage
Also, you're reducing demand on the grid by having them at people's homes, not just reducing the demand on the power plants. If the batteries were centralized you'd still need to move that massive amount of power over distribution and transmission lines, which is actually just as big a problem as needing to spin up a peaker plant. In many areas the bottleneck is transmission not generation
Long term, with people moving towards charging their cars at home, storing excess solar energy at home might be the more economical option because it decreases the amount of power a substation has to send out at peak times.
I guess Vermont’s relatively low population density makes that more likely; with lower population density each service station will either service fewer homes or require more cabling towards those homes. Either way, more cabling is needed per house. Upgrading that to handle the load of charging a car can be costly.
2-wheel dollies with motorized stair climbers are a thing too. Not super common, but aren't cost prohibitive for a use case like this where they'd see daily use.
Thank you for answering so many detailed questions on this.
Seems like recycling is picking up for lithium batteries and the metal components are still valuable enough.
I think a bigger question is if sodium batteries starts to take over (seems better for homes, heavier but seemingly safer but also for cheaper cars) and lithium/rare-earth metals prices goes down.
Lead-acid batteries are amazing for starting an engine, and terrible at basically anything else. They're slow to charge and very sensitive to over-discharge: it's generally recommended to never go below 50% state-of-charge (so you basically need twice the capacity in the first place), and even one full-discharge event will permanently reduce their overall capacity. The fact that they're almost impossible to over-charge means they're never paired with a proper BMS so they usually aren't protected against this type of damage. Also they need to be fully-charged every few days, so they're a poor choice in an application where they're constantly cycled.
Lithium batteries in contrast only need a ~10% buffer, and don't care about being topped off except for calibrating the BMS in certain variants (the only reason why LFP cars want you to charge to 100% regularly), so you don't have to over-provision as much. End-of-life is being sorted out as we speak, recycling companies are popping up as discarded batteries from cars are becoming common. Some may even pay you for them too.
Lithium-ion batteries have higher upfront cost then Lead-acid, but Lithium-ion batteries have longer service life.
https://www.whalebattery.com/blog-detail/lead-acid-vs-lithiu...
Cost per kWh per year:
lead-acid batteries: $100 per kWh per year
LFP batteries: $50 per kWh per year
https://www.justplugsolar.com/blog/lithium-vs-lead-acid-batt...
US is outsourcing recycling of Lead acids to Africa.
https://www.nytimes.com/interactive/2025/11/18/world/africa/...
You also need to buy twice the capacity for lead-acid, as they don't like to be discharged below 50%.
>Lithium is not the way to go for home batteries.
Turns out, they're on top of this.
https://cswd.net/cswd-in-the-news/vermont-expands-battery-re...
I was looking into this stuff early this year in India, and found LiFePO₄ more compelling on paper: two or three times the cost, but lasting two or three times as long, allowing deeper discharge so it should be equivalent to slightly higher capacity, and requiring no maintenance. I could easily have overlooked or misunderstood something, and am interested in counterarguments.
The lifespan numbers are lies. I have personal knowledge of deep cycle lead batteries lasting 10+ years, thousands of cycles. Many websites actually cite numbers for sealed batteries as used in cars. "Flooded" batteries last longer than sealed because they can be inspected and maintained. There are also "deep cycle" and "marine" units which are also different than car batteries and can be discharged more.
https://offgridsolarguide.com/lead-acid-battery-brands-for-o...
I’ve seen and heard of a lot of lead-acid battery home inverter and desktop UPS setups in India (extremely common due to grid unreliability). Desktop UPS batteries sound to consistently be completely useless (<10% capacity, typically 0%) in 3–5 years, and the larger home inverter batteries are typically in poor shape by around 5 years.
I haven’t known any Lithium-ion batteries yet, so I have no personal figures on them. But what I’ve heard is generally more like “they said 8–10 years but it’s still fine after 12”.
lead-acid does not like deep discharge. Also a UPS is typically going to have maintenance free batteries which don't last as long. Many UPSes don't have good chargers and will overcharge your batteries.
You can get decades our of a proper lead-acid battery, but only if you correctly account for all those factors. Start with batteries that you add water regularly (I'm not sure if this is monthly or yearly). Then make sure you have more than enough so that even in the worst case power outage they finish at 30% charge (meaning most don't get close to 50% discharge - the 30% an educated guess but needs more research for your conditions since this needs to be a rare event, the more often you get the worst case outage the more charge needs to remain after). Finally make sure you have a good chargers - modern "battery tender" (a brand name - there are others) makes a big difference.
Lead-acid has been used in major large installation and have a long history of lasting for 20 years when treated properly.
Lithium batteries are still new enough that we don't have a history. We have educated guesses, but those guesses tend to be conservative. Maybe they will turn out to last just as long or even longer. Only time will tell if they are as good or not. However we also know you can abuse lithium batteries and get much worse life. (the Nissan Leaf is famous for significantly worse capacity at 8 years)
The whole depth of discharge thing does make it harder to compare them. I said upthread “slightly higher capacity” for LiFePO₄, but I feel like by recommendations I’ve heard it’s more like 20–40% higher, which is really quite a bit.
Offgrid garage tested it a couple of videos ago and basically the battery lost capacity due to age and not for cycling. And that battery was made with the first generation of lifepo4 from eve, recent battery are better. Realistically it will die first the BMS than the cells in a couple of decades
> oldschool lead-acid are much cheaper
Source? Last time I checked a few years ago the prices were similar and lithium has dropped significantly since then.
That was the case before, but is it still? How do lithium battery costs compare to lead battery costs in late 2026?
Do you have a source for the cost benefit? Any lifecycle assessment I find says that Lithium is cheaper.
There are too many variables to make a simple statement. Lead-acid is a lot cheaper and we know how to recycle it. We also have a long proven history of lead acid lasting for decades in ideal conditions (which a house battery is more likely to hit than in a car).
However lead-acid does not like deep discharge so to get max life you will be using much less than the full discharge cycle 80%-100%, and so the lifecycle costs are very different. In some cases lead-acid can be more cost effective if you manage it well, but I would expect lithium to be cheaper for the typical case.
That is lead acid means your real goal is a cheap home backup, which you have to ride out multi-day power outages, and as a secondary you will sell some power to the grid, but you are not trying to make money doing this. By contrast I would expect lithium to make sense if your primary goal is to make money (or at least pay for your home backup system that can ride out a couple hours of outage but not days). The storage to ride out days could work now, but long term as your neighbors buy the system eventually there isn't the need for that much storage and someone gets limited.
And yet everyone is building with lithium, or occasionally sodium. Which leads me to believe that size/weight aren't irrelevant after all.
The technology with PbS or even NiFe has existed for decades, but only took off with lithium.
Not in homes. Density is a huge issue for commercial installations. The off-grid community also values user-repairabilty and avoiding vendor lock-in. Good luck replacing a dead cell in a tesla pack.
The market for this isn't the off-grid community. It's basically every GMP customer.
You aren't wrong about part of the off-grid community not wanting this. I'm not sure I'd want it if I were doing an off-grid install, but it does stand to grow the off-grid community to include people who are looking for a turnkey solution instead of having to do all the research to put together a more user-maintainable system.
Isn't the Tesla pack just a bunch of 18650 (or some similar cell)?
I wouldn't expect the home owner to repair them. However they should be repairable by someone with training in how to diagnose and replace failed cells. (which mostly means a battery welder and some safety systems)
I've put that link in the toptext. Thanks!
I'd feel better about this if they weren't charging people thousands for the batteries. As it is, this looks like a scam by utility companies to force their costs onto consumers and charge them for it on top of that. People should be being paid by the utility for storing, hosting, and allowing access to the power company's distributed infrastructure.
It's not as if the batteries people are paying for become their property, or are only for the homeowner's benefit. The utility company has the right to use that power however they want at any time including the "right to use all the energy in the battery". The homeowner also has to allow contractors, subcontractors, or third-parties onto their property. Physical access aside, they also have to allow the utility free access to their network and free use of their internet connection/bandwidth. The utility will not compensate homeowners for any of that.
Homeowners must also agree to install the utility company's cell phone apps/software. I'd bet those apps are collecting data and probably pushing ads too. They have to agree to the “Customer Privacy” terms, which will only be shown to them "upon installation of the Equipment".
The utility company advertises this as a means to prevent power outages (which, if they were doing their job in the first place, should be extremely rare occurrences), but the fine print makes it clear that homeowners should not assume that they will have any access to the power that battery holds in the event of a power outage or at any other time.
The utility also requires homeowners to agree to terms that state the utility will not be liable for any damage to persons or property caused by use of/replacement of/repair of/or the utility's failure to repair the utility's equipment and software. The homeowner also "bears the entire risk of loss, theft or damage" to the utility's equipment.
This would be a bad deal even if the utility were paying a monthly fee to homeowners. The fact that they've conned customers into paying the utility for using them, their internet, and assuming all liability/responsibility for the utility company's hardware is insane.
>I'd feel better about this if they weren't charging people thousands for the batteries. As it is, this looks like a scam by utility companies to force their costs onto consumers and charge them for it on top of that. People should be being paid by the utility for storing, hosting, and allowing access to the power company's distributed infrastructure.
I participated in this program early on (currently on year 8 or 9) and I don't think you're giving a fair characterization. First, the batteries took the place of a generator, and have reliable protected my buildings from power outages since. Part of the program is that in case of storm warnings or other risk it actually switches out from the VPP for the duration to protect you instead. So there's direct value to having them, particularly in a rural area of a rural state, regardless of any other money. Having a sizable generator isn't free, not just in terms of purchase but in terms of
Second, the utility did in fact pay with a pretty massive discount (around $5-6k per battery at the time IIRC). The amount they were willing to pay wasn't enough to completely cancel out the battery cost back then, but it was like 70-80% of the cost. And in general looking at all the various VPP programs in the region utilities remain very much willing to pay you per kWh, whether it's a lease or BYOB.
There are multiple ways to make a battery work for you in terms of ROI, and the math has changed over the years as various component costs have changed as well as being individual to each person's situation in terms of their own usage patterns and generation. But I don't think this was a scam at all, it was a genuine win/win even before getting into softer factors like reducing usage of fossil fuel peaker plants that a lot of us do really care about. In an ideal world neutralizing that carbon pollution would all just be built into pricing so the market could better sort it out, but as it stands I don't feel bad about supporting a shift to some extent too. And even though I'm probably going to just buy my own batteries next time around due to other changes, I'd certainly consider contributing to a VPP again depending. It's been a positive experience.
>The utility company advertises this as a means to prevent power outages (which if they were doing their job in the first place should be extremely rare occurrences)
This is just really hard in some parts of New England given the history of grid development (we have a lot of really weird legacy layouts), weather, trees, population density, and lack of resources. If you're at the end of a quarter to a half mile driveway in the forest up a steep mountain dirt road and aren't able to bury the lines then it can be tough in storms. Plus other weirdness, last year a pole came down and it turns out bears had been using it as a scratching post and just ripped through the entire thing. Was actually pretty cool but also a power outage.
>but the fine print makes it clear that homeowners should not assume that they will have any access to the power that battery holds in the event of a power outage or at any other time.*
In all these years it's never once been an issue though. And I don't consider that "fine print" but obvious: if you're participating in a VPP at all, then obviously there will be times when your battery has been drawn down. That's the deal duh. And with the best will in the world they can't predict things like some drunk driver taking out a pole and causing an outage (this happened again not that long ago). It's not impossible that there could be the bad luck of that happening right when the battery happened to be down to a low level. That's the risk. But they do pay you for it. And almost any way you'd make batteries pay beyond power protection entails some risk or else some cost too, like if you want to rate-shift so that you only pay the lowest night time energy rate by charging then and then running off your batteries during the day, then you'll of course be at risk of lower remaining storage if there's then a grid failure too when you were expecting to charge back up again. You can spend money on that risk in turn, but there's no free lunch here.
> it was a genuine win/win even before getting into softer factors like reducing usage of fossil fuel peaker plants that a lot of us do really care about. In an ideal world neutralizing that carbon pollution would all just be built into pricing so the market could better sort it out, but as it stands I don't feel bad about supporting a shift to some extent too.
We should be doing this as a society (or as a state or as a utility company) instead of relying on individual do-gooders to pay for it. 70-80% of the cost sounds very good, but if you're not getting any latitude on how the things are used, that 20-30% is still unfair. If they belong to the utility, the utility makes all decisions regarding it, and you are giving up your space for it, if anything you should be getting paid, not paying.
They could at least let you actively decide if you want to allow it to be drawn down and to what extent; some sort of latitude. As it is, for them it's money for nothing.
That being said, the article says that they're starting to install them for free. Thanks for sharing your experience.
It's not really a solution for the utility, it's a solution for the homeowner. The utility can't prevent all power outages or issues for all customers. Normally the homeowner buys a generator to deal with that. The battery is cheaper over time, much less maintenance hassle and less dangerous. The customer just wants their lights to stay on, they don't care how that happens.
>We should be doing this as a society (or as a state or as a utility company) instead of relying on individual do-gooders to pay for it.
Sure, but we aren't yet, at least not remotely to the extent required. And we all individually have benefited from the externalized pollution that fossil fuels have been responsible for, this isn't just some nebulous other thing right? It's not unreasonable imo that yeah, we individually should try to pay for that damage we ourselves "profited" from, even while simultaneously trying to vote and organize towards broader solutions. But feeding money into getting off fossil fuel is both directly personally helpful and broadly helpful.
>70-80% of the cost sounds very good, but if you're not getting any latitude on how the things are used, that 20-30% is still unfair. If they belong to the utility, the utility makes all decisions regarding it, and you are giving up your space for it, if anything you should be getting paid, not paying.
I don't agree with you, and it's my money, my buildings and my call to make. I've gotten a plenty solid direct benefit in ROI over the last 8-9 years for the $3k it cost me one time only vs the $15k a couple of PowerWall 2s would have been upfront and then the rate shifting and minimal solar I was in a position for at the time, or alternatively the cost of a new generator and then all the fuel and ongoing maintenance required. The $12k in savings thanks to the utility is money I could put into other investments that have had their own ROI since then. I do think the math now for me and a lot of others is different in 2026 then 2017, there are lots and lots of competitive battery and solar and inverter solutions now at radically reduced prices and that seems to just be accelerating, with sodium based systems and other tech coming. But that wouldn't have offset a real chunk of 9 years of carbon equiv release by me. The batteries got far more usage as part of a system for society then just me, and I still did ok even if it didn't perfectly maximize the individual dollar savings.
>They could at least let you actively decide if you want to allow it to be drawn down and to what extent; some sort of latitude. As it is, for them it's money for nothing.
If you BYOB you do get that choice, though obviously if you let them take less they pay less. But it's not money for nothing, just a weighing of risk/benefit.
>That being said, the article says that they're starting to install them for free.
The battery cost per kWh has fallen enough and I think they've gotten comfortable enough with the landscape shift that I can see that making sense now, not early adopter territory anymore. The utility is also in a position to realize benefits like having a bit more leeway in how they dispatch linemen for repairs, if they know someone is covered for 20 hours and it's currently 15 below zero with whiteout conditions that'll clear in 2 hours maybe it's worth something to be able to not have that be an emergency (or instead to direct emergency efforts to someone else who isn't covered).
>Thanks for sharing your experience.
I'm glad it's come up on HN. It's one of the few real rays of hope I find in all this, that despite failure of collective action it's just getting so good that the economics and politics are tilting anyway. Won't be fast enough to avoid a lot of bad effects, but it can always get worse so the faster the better.
> First, the batteries took the place of a generator,
The generator would have been yours, and only used for your needs. It wouldn't have involved any data collection, the uncompensated use of your bandwidth, or exposed you to so much liability.
> Part of the program is that in case of storm warnings or other risk it actually switches out from the VPP for the duration to protect you instead.
They may do this, but by their own terms they aren't obligated to. The good news is that in the event where a cable is cut/down and they lose the ability to siphon power from your battery you will be sure to get the benefit of whatever power it has stored. It's also nice that they compensate you for the power that they draw, but again, all of that energy is already theirs by right.
The state contracts them to provide the people with reliable power and you pay them for that service. They should be expected to reasonably deliver that in exchange. Installing their equipment inside people's homes can be part of how they manage that responsibility, but it's still their responsibility and they should compensate you for that and not expect you to pay them even more for the privilege of paying their costs and accepting liability.
> it was a genuine win/win even before getting into softer factors like reducing usage of fossil fuel peaker plants that a lot of us do really care about.
It's honestly not a bad idea conceptually. It seems like it can have real benefits, but the terms are exploitative. At a minimum they should be obligated to prioritize your power needs above others when it comes to energy stored in the battery on your premises, and they should be obligated to compensate you for power taken, as well as for providing them storage, access, security and bandwidth for their equipment, and they should also assume responsibility for any damage/harm their equipment causes to your property and anyone one on your property as long as it wasn't caused by tampering or improper use. Ideally, you'd also be able to opt out of all personal data collection (not related directly to the use/monitoring of their hardware), and any loss/theft/damage would be covered by their insurance (provided their equipment was reasonably secured), otherwise they'd have to pay you enough to get additional insurance coverage of your own.
I'm glad it worked out for you when you had it, but unless the terms were very different from what they are today you were absolutely cheated and being taken advantage of, even if you didn't feel that way.
Data collection is very useful and valuable to you when done right. We need to ensure the data isn't abused, but that doesn't mean data collection is bad when the data is used correctly.
The utility is well aware that power outages happen and make their customers mad. They want to solve them, but they also know cost matters and so that takes many ways to solve power outages out. Data used correctly from systems like this make power more reliable and it can be cost effective. By giving the utility access to this data they can better serve everybody.
Again, the key is that the data is used to serve everybody and not used for any of the abuses it can also be used for.
I don't see the terms as exploitative.
IIUC, the benefit for the customer is a battery backup that is much cheaper than buying the batteries themselves would be, plus the ability to make money when their battery is taken over for a few hours during occasional peak usage events. Provided the former override the latter, as seems to be the case, I don't see what the issue is.
I think you're claiming that battery backup shouldn't be needed in the first place if the power company was doing their job properly, since then there wouldn't be frequent outages in the first place. But I gather that this just isn't practical in rural Vermont. To put it another way: In that environment, a power company guaranteeing 99.999% uptime could not offer this at a price that is acceptable to most customers. So the equilibrium naturally shifts towards citizens tolerating more frequent outages than would be tolerated in, say, central NYC, and/or paying for mitigations like generators or batteries.
> IIUC, the benefit for the customer is a battery backup that is much cheaper than buying the batteries themselves would be, plus the ability to make money when their battery is taken over for a few hours during occasional peak usage events. Provided the former override the latter, as seems to be the case, I don't see what the issue is.
They don't get a battery backup. The utility company gets a battery backup and the customer pays a large percentage of that cost. The utility company isn't obligated to let the consumer who paid for part of that battery draw power from it, ever. They explicitly state that all the energy it stores is theirs, and that they can drain all of it away any time they want to.
Customers are being contractually obligated to shell out thousands of dollars, over a 10 year commitment they're punished for backing out of, obligated to not hold the utility company responsible for any damage they cause, obligated to take on a bunch of liability for things they have no control over, obligated to allow the company access to their property, obligated to allow the company access to use their internet service free of charge, and for all of that the utility company isn't obligated to do anything but install the company's equipment on the customer's property
All the customer gets is that maybe they'll be paid for the power the company takes from the battery (the company doesn't have to pay anything) and to maybe get to draw power from it if there's a service outage (the company isn't obligated to let them use any of it).
There are customers who say they are being paid for that energy and they have been able to use the power to avoid outages, and that's great, but that can change at any time and for any reason because the terms they agreed to don't obligate the utility to do either of those things. The terms explicitly say that all of the energy in the battery belongs to the utility company and they can use it however they see fit.
Maybe this utility company is the nicest company in the world. Maybe the utility company today would volunteer out of the kindness of their heart to rebuild someone's house if a software update causes the battery to catch fire and the customer's home burned to the ground along with everything in it, but the terms say they wouldn't have to do that and couldn't be made to. Maybe the company would never ever stop paying customers for the energy they take, or leave the customer without power while they drain the full battery to help restore service for businesses or wealthier customers. The terms would let them do those things though.
You shouldn't pay out thousands of dollars, take on a list of obligations, and expose yourself to huge risks and liabilities and then still be forced to just hope that the company will do the right thing, and keep doing the right thing for the next decade of your life. That's the problem.
>The generator would have been yours, and only used for your needs.
It also would have required constant testing and cost whether I used it or not, with no ROI whatsoever beyond power backup, a lot more noise/local pollution/size, storage of significant amounts of extra fuel (be it propane or diesel) with the resulting challenges, etc. Maybe the best bet and the one I was most strongly considering would be a PTO generator I could hook my tractor up to, then I'd get all the engine testing and fuel refreshing/storage "for free" on some level, in that I run the tractor anyway. But that still would have been dead cost most of the time, and on a basic but real human physical level, having to go out to the barn to hook things up and unhook them in the heart of winter wasn't a delightful prospect either. Propane doesn't go bad and maybe I could have finagled that into my heating system for a unified tank instead of multiple but that's still its own complexity, and place to house it and so on. And in retrospect that would have reduced the value of the heat pumps I've done since.
Batteries are nice. And I'm glad it wasn't only used for my needs. I like helping my neighbors, my town, and my state.
>It wouldn't have involved any data collection, the uncompensated use of your bandwidth, or exposed you to so much liability.
I'm definitely sensitive to data collection, and full local control has always been something I've cared a lot about and is a significant consideration going forward. But I've got the PW isolated on its own VLAN going through my OPNsense router, and the granularity of its perspective is I think pretty course. Given what I'm running I just don't think there's a whole lot, if anything, it can glean the power company couldn't already, it's pretty out there on the master panel so it doesn't even see just the house, use from the barn and office and so on is all mixed into the signal. Taking into account what was on offer and far tighter finances at the time I think I did the best I could.
This is also a case where I think some level of regulated, low granularity population data may be pretty important in terms of infra planning our shift to only renewables and a smarter grid. I'll have to keep thinking about that though.
>They may do this, but by their own terms they aren't obligated to
I'd have to double check if my terms from back then are different then what they offer now, but ultimately the fact remains that across hundreds of outages and blips over 8-9 years with a couple of devastating floods and storms in the mix it has never been an issue even once. These aren't megacorps, utilities here are pretty tiny by national standards and pretty responsive (as well as regulated).
>The state contracts them to provide the people with reliable power and you pay them for that service. They should be expected to reasonably deliver that in exchange. Installing their equipment inside people's homes can be part of how they manage that responsibility, but it's still their responsibility and they should compensate you for that and not expect you to pay them even more for the privilege of paying their costs and accepting liability.
GMP has I believe something like 10,000 miles of pole distribution lines for 265000 customers, but of course those customers are not evenly distributed, there are towns around here with literally double digits of people. And it's the biggest one, there are tons of smaller outfits and coops etc. "Reliable" doesn't mean "perfect" and never has, that's just not possible at the prices people can afford here.
I mean really, on some level everyone needs to be ready to contribute in general for life here sometimes. State is responsible for roads and such too, but if it's bad I and others get out our chainsaws (now electric! electric chainsaws are AWESOME) and winches and so on and get to work. State police provide coverage and will respond eventually, but it might be 30-120 minutes (or more sometimes). I've taken first responder courses, folks volunteer for fire departments and other roles, folks have guns. Others who can't do any of that can still bring people out clearing trees hot food and drinks and general support and that's a serious contribution and appreciated too. Dunno, not saying utilities shouldn't keep pushing hard and being pushed, nobody wants to be a floor mat, but I feel like they've been pretty solid and they really have been trying hard over the last few decades.
>It's honestly not a bad idea conceptually. It seems like it can have real benefits, but the terms are exploitative.
Some of your list feels like reasonable avenues for improvement, others feel totally unrealistic to a degree that it'd really end of restricting who could benefit. I don't think the juice would be worth the squeeze there. But BYOB is an option with a self-consumption plan, where rather then supplying power back you instead basically get disconnected from the grid during peak events, see [0]. The terms and conditions aren't nothing, but power infrastructure is pretty serious business and I'm not sure it's reasonable to expect the utility not to want some pretty clear control and terms around it. And if you want out of it looks pretty reasonable, 30 days notice and you pay back a prorated portion of upfront incentives and that's that.
Also, "bandwidth", seriously? I'm looking at Netflow for the electric infra VLAN and it's like, 1.5-4 kbps, with occasional spikes to... 25 kbps for like a second. Yeah we're the boonies and progress is slow, but nice outfits like NEK Broadband [1] have been working hard and we've got fiber now, and of course Starlink is an option, sometimes even cellular. But even on crappy old 5/1 ADSL like I had to live with for 20 years it's not much. Come on. Rural America isn't that far back, we've gotten a ways beyond 14.4k modems.
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0: https://greenmountainpower.com/rebates-programs/home-energy-...
1: https://get.nekbroadband.org/
You and I live in areas where social norms are to help our neighbours and contribute to our communities. GP seems to live in a place where relationships are contractual - he pays taxes and expects to be served in return with no effort on his part.
Often people from different societies have difficulty understanding how anyone "could live like that" - in both directions.
Helping neighbors and contributing to communities is great! Getting taken for a ride by a utility company isn't either of those things. The relationship with their utility company is literally contractual. They make you sign a contract! A contract with very bad terms. They're pushing some of the typical costs of running their business onto their customers, leaving them entirely responsible in the event that anything goes wrong, even when their customers do nothing wrong and have no control over the situation, and they are making the customer pay them for the privilege while not being legally obligated to provide anything in return.
Also yes, paying taxes should entitle someone to basic minimums like the ability to pay for clean drinking water delivered to your tap, and reliable power delivered to your home. We aren't a developing country, we're the richest nation on Earth. The extent of the "effort on my part" should be limited to signing up with the utility company and paying my bills every month. Everything else is their job. It's what they are paid for. What "effort on your part" are you making in your life to help your water company? Your cable company?
I am struggling here too. I think there are some decent points at the margins, but I can't get past the idea, "If this is the one place I am being exploited, I would be pretty ok with that."
> It also would have required constant testing and cost whether I used it or not, with no ROI whatsoever beyond power backup, a lot more noise/local pollution/size, storage of significant amounts of extra fuel (be it propane or diesel) with the resulting challenges, etc.
According to the utility company you should have one anyway because you may not have access to the power available in your battery even when it is full. Even when you need it, they can decide to send it somewhere else.
> And I'm glad it wasn't only used for my needs. I like helping my neighbors, my town, and my state.
In this case you're also helping your utility company and being charged for the privilege. How often have they helped you with something you weren't paying them for?
> These aren't megacorps, utilities here are pretty tiny
Your energy company is a subsidiary of Énergir. It's the largest power company in Vermont providing service to the vast majority of the state. They also provide power for New York, Maine and Connecticut. Énergir is also the largest natural gas distribution company in Quebec. This is not a local mom and pop operation.
> I mean really, on some level everyone needs to be ready to contribute in general for life here sometimes. State is responsible for roads and such too, but if it's bad I and others get out our chainsaws (now electric! electric chainsaws are AWESOME) and winches and so on and get to work.
How much do your neighbors charge you when you help clear the roads with your chainsaws? Do they make you legally liable for any damage to cars if there are accidents on that road after you helped clear it? Would it be absurd if they did?
If you really want to volunteer to help host/power/secure/connect your utility company's infrastructure for them that's very sweet of you, I'm sure that will save them a lot of money, but they are also charging you a bill to do it for them and then they're leaving you liable for things entirely outside of your control while also making you agree that you'll be responsible for any harm caused by their equipment. They aren't being your friend here. They aren't looking out for you. They aren't acting like a part of your community. They are charging you and your state money, externalizing some of their costs and risks by putting them onto you, and charging you thousands for that.
> the generator would have been only used for your needs.
God forbid we live in a world where sharing and helping others is OK.
Sharing and helping a giant state monopoly doing their job they are already obliged to do, but incapable of doing themselves?
I think there are better ways of sharing and helping.
This thread shows the difference between a high and low trust society.
A high trust society doesn't cause a monopoly to become efficient. A society where everyone is thinking of the common good is the one where individualism works, because then you have no need for a giant bureaucracy trying to coerce everyone into doing the right thing, since they would do that of their own accord.
But the disadvantage of bureaucratic authoritarianism is even larger in a low-trust society where everyone is in it for themselves, because then you can't trust the bureaucrats not to be corrupt and they're still sitting on a monopoly.
Which is to say, what you always want is a high trust society and what you never want is a monopolist.
"A high trust society doesn't cause a monopoly to become efficient."
Actually it very literally does.
Unless you are completely off the grid, you are getting power from a local monopoly. This is baked in. You get your water from one source, send your sewerage to one source, get your power from one source, etc. So then the question is how to make the monopoly well behaved and how to keep them that way.
Having a giant state monopoly with an obligation to do a job is one way large societies share and help each other.
Why aren't they installing larger batteries at substations instead? That seems like the economically optimal middle ground.
It's more economically optimal to convince wealthy Vermonters to house the batteries by branding it as subsidized resilience than it is to buy and maintain substations?
They already have substations, I assume? You can buy grid-scale batteries in a rolling container and just park them.
Right, but people are spending for resilience anyway in places like Vermont, it's a way to harvest that money.
If home owners are paying then it might be less efficient for the overall economy but better for the utility company. It is often easier to find a million people willing to spend a thousand dollars than finding one person willing to spend a billion.
There’s probably a significant element of consumer batteries being so good, so easy to setup, and so cheap to buy. That it actually ends up being more economical to take this approach, than build dedicated utility scale battery storage.
With consumer units, you can reasonably expect that they’ll operate with zero maintenance and zero direct supervision for a decade plus. If the cost of those units is low enough, that reduced operational burden starts looking very attractive, especially if you want to scale up your battery capacity across your network very quickly.
>With consumer units, you can reasonably expect that they’ll operate with zero maintenance and zero direct supervision for a decade plus
I highly doubt it. You can reasonably expect one hard drive to operate just fine for years, but data centers have to constantly replace failed drives, and that would still be true if they they put each one in a different building. It would just cost a lot more to do.
> That seems like the economically optimal middle ground.
It is not when we are talking about government subsidies intended to redistribute wealth from the poor to the middle class.
Home batteries provide backup power in emergencies to the home without a substation being involved.
But they don't provide a real utility service that serves everyone (e.g. tenants in homes they don't own).
>It's not as if the batteries people are paying for become their property
It is as if. The article says it's a lease agreement, and provides this link.
https://greenmountainpower.com/rebates-programs/home-energy-...
>the homeowner "bears the entire risk of loss, theft or damage" to the utility's equipment.
What are you quoting?
It's a 10 year lease agreement. You pay them, and when the 10 years is up you have to return the batteries. At no point does the customer own the batteries.
It's like leasing a car, except with a car lease you have the option to pay extra to buy it out at the end and take ownership; with this lease agreement you don't.
This is like leasing a car except that the dealership can show up with other customers to take "your" car for test drives or just to drive it around for any other reason whenever they want to, for however long they want to, and they won't pay you back for any of the gas they use. Basically turning your personal garage into their distributed showroom.
IIRC pre-covid when the program was quite new, customer could buy the batteries outright. Later on they added the lease option.
One of the issues with these is the limited storage capacity. While it is nice for short outages, there are sometimes multi-day events in the winter. I think the longest was in the late 90s from an ice storm and was over a week. If you have solar, less of an issue but not everyone does (though solar does have surprisingly good install base in Vermont).
I've not checked to see if GMP limits the install locations but do recall some states/munis trying to limit them to outside the home due to fire risk.
Do you really want to buy 10 year old batteries?
Linked from that link: https://greenmountainpower.com/wp-content/uploads/2026/04/ES...
I hope that the system designers know what they are doing in Vermont.
The way an article is written doesn't explore the fact that at its core batteries are a 'consumer of energy' and not a producer like a power plant. You are losing electrons through heat losses and degradation in a bid to match demand with lowest cost supply.
Replacing generators with a battery make sense when the peak capacity is overbuilt, but it shouldn't be left unchecked.
The other challenge is that the customer's savings usually come not from the battery itself (the energy arbitrage) but from avoiding the usage charges from their distribution and transmission networks. Deploying batteries on grid without a plan pushes forward the grid death spiral where some users of the network feel like they no longer need to be connected as they can be self sufficient. That means that those that cannot be self sufficient have to share the same cost of infrastructure with less users on it. That is assuming that being self sufficient is economically viable and sufficiently reliable.
Those who think that home batteries and solar are 'cheap' should look into the true underlying costs. The per MWh cost of a home system is MUCH more expensive than a utility scale system. The savings are often just an arbitrage on a relatively high level usage-based pricing allocation of the transmission and distribution systems.
The network costs are mostly fixed by their nature - it's recovery of equipment cost and ongoing cost of maintenance activities. Cost per KWh can be different at different times because you need higher cost equipment that works during the time of high load. If there is no high load - the equipment is not needed and cost can be reduced. But this cannot happen overnight because the equipment is already there! Without forcing the networks into taking heavy losses - you have to allocate the costs to users,and unfortunately those that cannot afford to have these expensive home systems will end up paying the higher price. In effect your battery 'savings' are coming from people who cannot afford to have one.
I agree on all points. This is a short term cost saving measure at the expense of long term energy security. Batteries do help smooth the considerable volatility introduced by renewable generation, but unless they want a significant share of houses and industrial sites to have large batteries (which would cost FAR more than just keeping the power stations online), they still need base load generation.
Unless this is very carefully managed (and I do not think governments are generally capable enough), this will result in a lot of new problems. One will be major difficulties in developing new housing (or intensification) due to lack of electricity supply. Another will be insufficient supply during 99th percentile events in which home batteries alone will be insufficient to close the gap. Another will be distribution. Some neighbourhoods will have higher battery penetration than others, and this happens organically and without the permission of the grid companies. That's very difficult to plan around. Some areas are going to be secure, and others will not, unless the grid purposefully oversupplies, negating the potential cost savings.
Batteries are good at marginal demand smoothing, but I am very dubious about shutting down energy generation. Especially at this time. All analysis points to the reality that due to technology demands, we're facing an imminent power generation crunch. Prices are going to rise everywhere and demand will only increase.
There is no local "base load" generation to begin with. 73% of power in VT is imports from out of state/country. Primarily from Hydro-Quebec.
- There are no coal plants left in New England at all.
- Most of VT doesn't have access to Natural Gas (the Burlington metro does, via a pipeline that is only served from Quebec, it is not connected to the US pipeline grid). There are no Natural Gas plants in the state.
- The nuclear plant closed over a decade ago.
- Actual in-state generation on a normal basis is a few biomass plants, some modest hydro on the rivers, and some scattered wind/solar.
- The power plants being "replaced" here, or at risk of being replaced, are some small and rarely used oil-fired peakers that run a few hours a year currently and have nameplate capacity in total of <200MW even if they shut down all of them.
- Transfer capacity to stressed regions (NY-ISO, PJM) is low so they can't really draw that much off the region's grid (ISO-NE).
- Power prices are always some of the highest in the country, the region in general is known for regulation and disliking development - and VT even more so. Making it unlikely you see some sort of AI data center boom here or the like.
- The most realistic source of significant new demand in the state is probably electrification (heating, cooling, vehicles).
> they still need base load generation
nit pick, but this isnt true at all. "Base load generation" refers to fixed capacity generators (coal, nukes) that run at 100%, matched to the lowest point of the demand curve overnight. This is an obsolete concept in a modern grid where batteries, wind, solar etc have destroyed that economic niche.
what you mean is likely "backup capacity". And yes heavily renewable grids will likely need some standin / backup generation for exceptional circumstances, for the foreseeable future. The economics and sizing of this backup is almost entirely unrelated to the economics and sizing of "base load generation". (for eg, there will never be a time when a diversified grid is at zero. The amount of backup needed is a function of how frequent these exceptional events are, the mix of your grid, and how much you're willing to pay backup generators to avoid load shedding in these situation)
Entirely agree. I think that this is fantastic technology and it will do wonders to avoid blackouts and deal with storm outages that people talked about. I just think that we need to have more care when it comes to energy.
Turning off plants is a lot easier than turning them back on. Especially when the rest of the world is building data centres and co-locatrd power and there are skill and equipment shortages.
These technologies bring a promise of clean renewable power which is great, but reality is that we haven't fully figured out how to do it reliably enough. I fear that we will get to a stage when old conventional plants are shut down, and we still haven't fully figured out the replacement. It will be a long period of unreliable and expensive power which will undermine entire economies.
The article does not make a big enough deal of another saving for the utility - it means that when snow takes out lines, they have more time to deal with the problems before customers start complaining. That can be quite significant if the utility can wait 12 hours for storms to pass, then fixing things becomes significantly easier.
I'm not sure how much of a benefit this is. Many/most houses/commercial sites won't have batteries (or at list some significant minority). They'll still complain. Power companies will still have a duty to restore power ASAP for health and safety reasons. Either way, they'll only repair the lines when it's safe to do so, and they'll continue doing that.
In Sweden we solved this by putting most power lines under ground and Sweden has the same population density and is larger. Power outages during storms is a thing of the past in most of Sweden.
Not saying this option would be better, we started this project way before batteries was a realistic option.
When coupled with solar, batteries are absolutely a net producer of energy. Around the clock too, as it allows solar generated at low-demand times to be redeployed when needed most.
That could be true, but I think important to clarify - how big is the solar array and how big is the battery? - what does the consumption look like - is your battery big enough to help navigate through a week of cloud cover in winter? - do you live somewhere with great solar resource
I don't understand comments like this. This isn't theoretical. This already exists in reality. It is reducing demand at peak times. It is preventing outages in rural areas during/after storms. It is so successful they are closing down power plants. I'm guessing you don't like solar/batteries for some reason? I don't know. This comment confuses me.
From the article
>More than 5,500 people in Vermont have similar home battery systems.
This is _literally_ a rounding error. It's less than 1% of Vermont.
So it's your comment that's truly baffling, though I'm sure others would appreciate if you posted your own source. There's certainly no power plant getting shut down because 5,500 customers have batteries, but again I'd love to be proven wrong.
It's in the article. Give it a read.
Do you think I made up the quote? Should I quote it again?
Parent was just spreading a lot of fud, half-truths, and "yeah, maybe if you squint and force an exotic framing"... they're trying to convince you to throw the baby out with the bathwater, don't lose sleep about it.
I tried to signup for this program but the building code gets in the way. You need 3' from both edges of the battery to a window or door. I don't have a wall with 8-9' between windows. The alternative is to build a fire proof room in your house which takes up a lot of space. Ultimately it was not worth it even with all the financial incentives. The rules might seem innocuous but they're a dealbreaker. It's far easier to get a propane or diesel generator installed.
Which is kind of wild, because generators powered by combusting fuels are also giant fire hazards (and produce noxious CO and other gases), of course.
Generators are generally used outside. There are some rated for use inside, but they also have strict regulations on how that is done. (there are also some used inside but they will kill someone soon)
Batteries can also be located outside, of course. There's still fire risk (from both) due to proximity.
Maybe where you live, but where I live the temperature outside is bad for batteries.
Though what is "inside" is debatable. My car can sit outside because it has the batteries in a case that is climate controlled when needed, and so the batteries count as inside even though they are in a car that is outside.
I would be much more nervous about a 13+ kWh battery than a natural gas generator.
The generator is generally only risky when in operation. For natural gas units, a normally-closed solenoid keeps the gas off unless the controller actively commands it. A battery is constantly in a state of non zero fire risk when charged.
Taking out a window and putting the battery in front of where it used to be was no option, I suppose?
Why downvoted?
We have this in CA. I have Tesla batteries and they promote wanting me to enroll my batteries into a larger grid so their capacity can be used during higher load events.
I thought it was a novel idea when I heard about it.
Tesla Electric customers report making as much as $150 a day: https://electrek.co/2023/07/05/tesla-electric-customers-repo...
> Tesla Electric customers report making as much as $150 a day
Only on peak demand days, of which there are only a handful every year.
I have Enphase batteries enrolled in an equivalent program, so I've tracked how much I make. Definitely not enough to make much of a dent in the payoff time for the batteries. But a nice perk nonetheless.
there is something really wrong with the economics of this.
it shouldnt be celebrated.
It seems like an unreservedly good thing if people with home batteries can help prevent brownouts and reduce prices for everyone else. Also, I believe the $150/day figure was during a rare heatwave event when prices had surged to 100x their typical value ($5/kWh). It’s like any other investment where you outlay cash upfront and hope to make it back over time, whether via reduced costs for your own electricity usage or selling it back to the grid when doing so is profitable.
Makes sense to me. Peaker plants are typically expensive (even at idle) and polluting.
During peak need, renting some capacity from subscribers already on your grid means you don't need to build another peaker plant.
What is wrong with this?
Its an inefficient use of capital.
Whose capital?
The people buying the batteries and the government's capital. It only benefits the private util companies.
The better option is for the government/utility company to build out the required storage for a fraction of the cost.
And when the power lines fall down in rural areas, how will people heat and power their homes? I guess they could buy some batteries, but then they'd sit idle most of the time. Maybe they could find some other profitable use and share the capital cost?
> better option is for the government/utility company to build out the required storage for a fraction of the cost
Ex ante, sure. Right now, the existing batteries are a sunk cost the utility didn’t have to pay capital costs for. The right answer is to do both.
> The people buying the batteries and the government's capital.
The former should be allowed to make their own decisions. I agree that the latter should probably be kept out of this: government is usually not very good at making these decisions. But alas, in many places they play a huge role in the electricity supply and distribution.
> The former should be allowed to make their own decisions.
Yes, but that's how we arrive to local economical maxima that are much, much closer to the global minimum that to the global maximum. The personal decisions aggregate, after all.
People are buying the batteries with their OWN capital, not Govts capital.
You say Govt capital which only benefits private utlities and ALSO say govt/utility should to build out the storage. Not sure what you are trying to say. You sound pretty confused.
In a lot of places the power companies are government owned and the private companies get massive amounts of captial from the government for buildouts.
holy shit, yeah. you dont see a problem with earning "over $5 per kWh" ?!?!
Be more explicit. What is wrong with this? It's not all the time, it's only in times of extreme need.
Variable pricing like this enables all sorts of cost saving technologies that bring down the cost of the grid and generating power for everyone, by spending a lot for a very short time, instead of building tons of extra large assets that sit mostly idle.
If somebody is providing a service that operates on the whole sale market, they deserve to get paid like all the other generators that are helping to keep the grid running in these times of need.
Peaker gas plants make this much money all the time. But you see no problem when its fossil fuel generation. But its a problem when people get paid?
Not only do peaker plants make the most bucks/KWH, but they increase prices for all generation because of how auctions operate.
for single individuals to earn as much as (i assume US$) 150 a day means that the grid is horrendously unbalanced.
hell if I emptied my 30kw into the grid in my state/country at the most expensive time I'd earn AU$21.00
to earn US$150 means either HUGE battery capacity (and transmission capacity) or utterly rediculous power pricing... both mean really lousy power supply and grid design. I'm all for indipendance but the reality is we live in communities and count on the collective to rise us all up together.
that sort of profit is a clear warning sign of a broken community.
It depends a lot on the market, but before there were lots of batteries this was extremely typical in the Australian grid. You probably just weren't exposed to it as a consumer! Massive price fluctuations were the impetus for one of the first large scale grid batteries in Australia, and the batteries worked really well to solve it. It doesn't happen often, and nobody is getting paid $150 every day for their home battery. It's just for the extreme events.
As more and more batteries are deployed the price swings will decrease.
It's not a "broken community" it's just end consumers being able to help out in times of great grid need and getting compensated fairly for it.
It's more efficient for the grid to be very unbalanced every once in a while, rather than building so much it never happens.
And it's not a sign of a broken community. Those batteries aren't making all that much money on a per-year basis. And the earlier batteries into the system are going to make the most money. The more batteries that get built the smaller the profits will be and the better the entire grid will be.
California rate payers are being forced to essentially pay for fire insurance for CA residents who live in tinderbox areas, by way of PG&E rates, and burying lines that serve widely dispersed populations. That's the big difference. The vast majority of US residents have much lower utility rates.
Yes, only the billionaires have the right to make money. Think of the horror of any person making money by producing/storing energy!
California Virtual Power Plant, Tesla view: https://www.tesla.com/vpp/california
It is actually a pretty great way to address marginal demand spikes without overbuilding generation capacity. With the fringe bonus of local protection from short outages.
I wonder what the cycling does to battery lifetime?
How much for a decent home battery setup? Already have 15-year-old 4.2 kW system and lately, PG&E isn't really giving us anything for our power..
I like the idea of a home battery systems. I live in a place with frequent winter storms and also hurricanes.
Grid storage large containerized batteries is a great idea too. There's even a local company (Aspin-Kemp) that makes them and also marine hybrid boats. The electric company here is a dinosaur wanting gas turbines and no interest in renewable energy just profits for shareholders. They even got caught with their pants down after a hurricane trees fell on power lines due to no tree maintenance for 40 years.
One issue with large battery storage is fires. Where I live is small and island with small towns the biggest city is at best 50,000. The next smallest city of about 15,000 uses grid storage batteries one of which recently caught fire and burned for a week. It's in a small town so the toxic smoke was a big problem. It would be very bad for a home battery system to ignite that's likely why my city does not allow home batteries inside homes.
A new method to douse battery fires needs to be developed. A week long fire and toxic smoke is very stressful.
If there is a risk of that catastrophic of a fire, why would I rush into strapping one of these to my house?
If a home had a detached garage or a storage shed that would be a better area. Some of the newer model batteries can be outside in winter cold and snow on its own base like a stand-by generator would be.
I like the idea of a backup system or a system to offset high rates by storing power on off-peak times. Even if you don't have solar storing power from the grid at low demand times at night then use power from the battery at high energy cost times during the day.
Whatever way it's installed it's still a good idea to have an emergency plan or at the very least assume the worst and place the device away from the home.
This is a somewhat similar idea to what Base Power, based in Austin, is doing: https://www.basepowercompany.com/?base_vid=2f8f0609-a7e5-4f2...
Pretty neat! Time shifting renewable energy for later use
I think there's suppose to be a feel good in here, but it feels like another race to the bottom. Power companies dont invest their profits they take them and then when the grid becomes unreliable put it on the customers with interesting excuses and eco-fashionable handouts to help the pill go down.
This is not the experience on the ground in Vermont.
A bunch of people are commenting that this could lead to grid-death spiral where people opt out of the grid because they can just use solar + batteries. Maybe, but I doubt in Vermont. Vermont is really hard for solar because of tree cover and clouds (according to my conversations with a solar installer). Secondly, in this setup you have buy your own power plant (solar + batteries), which likely for most folks, is a pretty big expense. Green Mountain power subsidizing the cost of buying the Tesla power walls is a big deal for me because I use this setup for a cabin / second home and want to keep my costs relatively low. I can't do solar because I on the side of a mountain and lots of trees.
"Megan Browning says she hasn't lost power since installing solar and two home batteries around a year ago"
I live in Europe, and I can't even remember the last time there was a power outage. And all of this without any local battery storage.
So all Europe are managed the same way?
What do you know about how the grid is operated anyway?
"Works for me, so must work for everybody."
out of the few places ive lived, seattle is the only one that had power outages on a regular basis.
maybe not all of europe is good, but at least many places in the US are bad at it
I live in the US and I also experience almost no power outages. And no battery storage.
I live in Europe and I have had 7 power cuts this year. I don't even bother resetting the time on my thermostat. Local town is 8km away, 200k people.
Most likely because you have a) buried power lines and b) less exposure to destructive storms.
I love this. It’s basically an edge cache for power, with an enormous amount of side benefits - smooths out solar power, smooths out the duck curve, and allows the grid to size closer to the average load and absorb the spikes at the edge, instead of cascading into the core.
There was an article earlier about the distribution challenges that come from large workload fluxes, too - tl;dr is the transmission lines get less efficient under higher load, so smoothing out the demand curve to the end user also raises the efficiency of the entire grid.
And as someone points out below - the proliferation of EVs also helps this, because they can act as a “deep” reservoir so the local residential batteries can be much smaller - more buffers than something expected to run the house for more than a couple hours, so that makes the whole setup even cheaper, depending on when and where the EVs are getting charged.
Yep, flatten the peak means you can spread the cost of the transmission grid over more electrons, lower the cost per unit of energy.
And with the way that grid costs are coming to dominate electricity costs, these sorts of peak shaving technologies will be huge cost savers in the future.
This comment needs to be higher than all the "but storage is not generation!!" fud in here. Didn't realize how astroturfy hn had become. "edge cache for power" is the true spirit of what this is about
> how astroturfy hn had become
It feels like politics to me, and HN is definitely not immune to partisan motivated reasoning.
What is average length of outage? If it is a few hours then the battery seems like a good idea. If it is days then the battery will probably run out.
> around 50% of the houses in its programme with home batteries also have solar panels
I'm assuming most of these outages are from snow storms. Do these people have to go up on the roof and clear the solar panels?
In my experience as a VT homeowner we have relatively frequent short outages. It's pretty rural and the weather is brutal. I think the grid doesn't have as much redundancy as denser areas. We had one 3 day outage 2 years ago in the middle of winter which got quite dangerous, but otherwise I haven't had anything more than a few hours.
Also we have propane heat - but I need electricity for the blower and control board. So the electric consumption is pretty minimal, but it is critical.
If you're in a power outage with solar and a battery you are so much better off than without that.
Assuming they set up the house to island, which depends a lot on the install. Otherwise live power from a house in an outage is a big risk to those working on solving the outage.
Easily solved, if addressed!
You also need to take into account the fact that VPP systems like this stabilize the grid by flattening the peaks and troughs, and reduce the average length of outages.
Most are hours but there are enough that are a day or more that it is a valid consideration. As to when, honestly I think there are more not snow related. Long stretches of wet (or floods) and high winds not a good mix.
In New England for decades and power outages >12 hours were very rare for me and I don’t recall any >24 hours. Multiple states and downtown/rural.
I live in Vermont. This is the first I've heard of this. But I like it!
I live just over the border in Massachusetts and we have something similar, called ConnectedSolutions. It is essentially the same kind of program except that the benefit is a 0% loan on the battery purchase. I have a 15kW battery that allows me to power the entire house overnight without drawing from the grid. When the power company wants to draw from my battery, they send me a notification through my battery’s app. I can opt out some fixed number of times, too. And, just as when my solar runs net negative, the power company pays me (in bill credits) whenever the virtual power plant draws power.
Just found out about this. Any big draw backs to enrolling in it?
The only drawback, really, is that sometimes you _want_ the charge in the battery for yourself. If you take out a loan with a ConnectedSolutions clause (e.g., a MassSave loan), you are obligated to make your home battery available as a VPP under the terms of the loan.
Fortunately, one of the valid reasons for opting out from a "VPP event" (which is what my battery mfgr's app calls it) is a coming storm. In fact, in my system a "storm hedge" (where the battery tops itself up before a storm) trumps a VPP event, so for all practical purposes, there is little inconvenience. So there aren't really any drawbacks. And when you are done paying your loan you can either stay enrolled in ConnectedSolutions or not.
I say go for it. A 0% loan is great, and it was the deciding factor for us to buy the battery. Honestly, I wish I had bought a bigger battery! 15kWh is good for an evening, but not quite enough if the following day is rainy.
Nice! Any recommendation on brand?
I bought a FranklinWH, both for technical reasons and because I could not in good conscience purchase a Tesla battery. I like the FranklinWH. However, I discovered that it is extremely chatty with a large number of hosts located in China. Most of the hosts it chats with are hardcoded IP addresses. This worries me a bit, not for xenophobic reasons, but because it strikes me as brittle. That said, I did end up putting the device on its own (firewalled-off) subnet. Although the app is kind of opaque, it works fine, and I mostly get the information I want via HomeAssistant, which has a FranklinWH plugin. I'm not sure if I would buy it again but it gets the job done.
My other equipment is mostly SolarEdge, which is excellent and well-behaved. SolarEdge now has batteries too-- I would probably look into them were I to buy a battery again.
A couple things to note. If you get a battery do not put it near your house. Generally, energy storage has a good safety record, but if they do experience thermal runaway, the fire effectively cannot be extinguished until all the fuel is consumed. Mine is 75' from my house because I have a solar groundmount array. Second, my solar installer initially set everything up using wifi, including a high-gain antenna because the array was so far from my house. I pointed out that I had an ethernet switch in my basement, so they ran hardwired networking through the power conduit to my house. Much more stable. Just ask for ethernet upfront if you can.
It would be nice to change the headline to "Vermont is replacing power plants with home batteries." Shorter and potentially saves a click.
Except they're not replacing power plants at all, they're adding batteries to the grid to store and distribute power. After all, something has to charge the batteries.
>The US now has over 40GW of virtual power plant capacity, according to internal analysis by Wood Mackenzie. It's still relatively small compared to the roughly 600GW of natural gas and 200GW of coal, but a total of 160GW of capacity could be unlocked by 2030, according to a 2025 US Department of Energy report – equal to some 20% of the country's expected peak energy demand.
>Through GMP's programme, its virtual power plant has quietly become Vermont's biggest source of power. Now, the state is testing how far this "hidden" form of power can go.
Does anybody at the BBC actually understand what batteries are, and why they cannot possibly compete with power plants!?!?
> Does anybody at the BBC actually understand what batteries are, and why they cannot possibly compete with power plants!?!?
VPPs displace more expensive generation capacity at the margin. Because your marginal loads are for relatively short durations. It's actually quite smart, especially if you can get end consumers to subsidize it.
Batteries compete with peaker power plants, though.
Batteries compete with peaker plants for diurnal variance, but they can't replace peaker plants for seasonal variance. It's an interesting dynamic.
Are there peaker plants that come online for seasonal variance?
Is that a local question for Vermont, a nation question for the US, or a global question?
If the question is global, then yes, there are, although as renewable energy has increased globally so has the need for peaker plants to handle the variance in the grid, thus plants that historically has only been used for seasonal variance are now used all year round to handle weather variance. An example of that is the oil power plant in south of Sweden.
I think what he was saying is that with a peaker plant you have an extra source of power. So if you have a low wind/low irradiance period - you can rely on peaker to provide more power, but by this stage batteries are long gone.
There is a coal power plant near me which in recent years I saw it running only during winter.
What do you mean? These numbers provide great guidance so that people can understand the size of the battery discharge, and what they could replace.
Batteries do indeed compete with power plants, every day of every moment they are on the grid. They are also consumers from power plants, they go both ways.
Power isn't a particularly helpful metric here, energy is. Power doesn't tell you anything about how long the batteries will last, it only tells you how quickly they can drain. Also there's a limit to how much power you can draw through residential lines so regardless of whether or not batteries can deliver power on the same order of magnitude as a coal-fired plant, it's highly dubious that these specific batteries can do that.
>Batteries do indeed compete with power plants, every day of every moment they are on the grid. They are also consumers from power plants, they go both ways.
Hey don't tell me that, tell the BBC. They're the ones who wrote an entire article about "replacing power plants with home batteries".
They literally did replace power plants with these batteries though. From the article: “ GMP similarly used to rely on oil, diesel and natural gas peaker plants to meet peak demand. Now the company's virtual power plant has effectively replaced them, says McClure. "We've been slowly able to decommission those as they've become end-of-life," she says.”
I don't think the BBC is confused here at all. Batteries do indeed replace power plants. They are already actively replacing gas peaker plants all over. In California, batteries they are dramatically reducing regular, non-peaker, gas turbine generation, by outcompeting them on the grid.
> Also there's a limit to how much power you can draw through residential lines so regardless of whether or not batteries can deliver power on the same order of magnitude as a coal-fired plant, it's highly dubious that these specific batteries can do that.
These specific batteries, on the other ends of residential lines, indeed do push power back on the grid in aggregate enough to replace coal power plants. There's nothing special about a point generator on the grid versus the aggregate action of thousands of batteries on the other side of the distribution stations. In fact that's what's so amazing about batteries versus large thermal generators: thermal generators are large because if they get super inefficient when they're not large. Nobody is installing a small coal generator at their home to run daily, and even small diesel generators are hugely inefficient. But batteries are so useful that even accounting for the extra expense of large numbers of custom installs, they reduce grid demand enough to make a ton of financial.
And power is indeed the most important metric when it comes to the grid. It's how everything is run, how individual grid assets are dispatched, because power needs to be balanced at every moment. Somebody could throw an asset on the grid that only dispatched for 15 minutes (or whatever the minimum bid time is), and it would still be described primarily by power. Capacity decisions may be made in kW-month or whatever unit, but you can run a grid on a pure energy market without any capacity market at all, as ERCOT shows.
I agree with how power is a bad way to measure batteries a lot of the time (though if you assume they last 4 hours you shouldn't be too far off).
But I don't think the residential line limits are too bad. A house that's sending out power takes its load off the grid and can also power multiple other houses without any lines being overloaded. And if an area has a high enough battery:house ratio, the full megawatt capacity of powering those houses but flowing the other way is a ton of power. (If the equipment can handle power flowing both ways.)
I wonder if increased reliance on VPPs increases the difficulty of a black start. Especially since these things are internet controlled, I can't help but feel like there's a bit of a circular dependency. Can't coordinate the VPP without internet, can't have internet without power, can we black start without coordinating the VPP?
You can't do a black start from the lowest potential part of the grid anyways. Synchronization isn't the hardest part. You could solve this with GPS and cellular telecommunications. Fault current handling is where things fall apart. You have to start the grid from the top. Fault current has to flow in the right direction or none of the existing equipment will function correctly.
The power walls can help to stabilize islands once they're back online, but they can't meaningfully participate in the initial phase.
That's an interesting question. I would think that it depends on what generation the batteries are replacing. As far as I know VPPs are relying on domestic inverters that do not have grid forming functionality required for black start. So you essentially have less plant capable of black start which I would think makes your black start capability worse.
http://archive.today/2MIaJ
I couldn't read the article because of paywall issues. I have a Tesla powerwall that I pay $50 / month to lease from green mountain power. I have piece of mind for power in a rural area - the power company get peaker benefits. Seems like a great deal. I wish we had this in Massachusetts. Mad river valley area.
Why not install a few megawatts at the substation? You would have much lower overall install / maintenance / upkeep and better safety.
Unless they expect the consumers to bear a larger cost over the long term?
Any news on the sodium based batteries? Cheaper but heavier would be perfect for home batteries
DER (distributed energy resources) is getting popular. This program is like a UPS for the house.
This is something I've been thinking about a lot.
The way an electricity utility works, you need power plants (or to buy power from someone with power plants), transmission lines and some form of last mile delivery. You have substations and other infrastructure too. That infrastructure has ongoing maintenance costs but also capex to build it in the first place.
So your per kWh price is the sum of the electricity cost, the maintenance cost and the amortized capex plus some profit.
Utilities are heavy regulated but only the electricity cost tends to be highly regulated. Any maintenance or capex costs can be passed on directly to the consumer. Private equity has realized this. Data centers have realized this where they can negotiate a lower electricity rate and the build out for multi-gigawatt transmission and power generation can be passed on to consumers. This has gotten creative enough that people in unrelated states end up paying more because of upgrades required for shared infrastructure for interstate utility compacts.
The obvious endpoint for all this is for users to eventually opt out. Disconnect from the grid and use totally renewable energy plus batteries. Generally in any urban environment you can't avoid the monthly connection cost even if you use no power. The city will declare your house unlivable. I can see this changing in the coming years with soaring prices that basically go to share buybacks and bonuses for private utilities.
But what if the connection to the grid drops significantly shifting maintenance costs to the rest?
I think the future is going to move away from large connected grids towards self-sufficiency and smaller localized grids, ideally municipally owned. But you can't gradually move from a large grid to smaller grids like this because of the problems of who pays for the grid in between.
I think you are spot on. The grid death spiral. Unless you can have enough generation co-locatrd with consumption you need the grid and the utility scale plants. In the densely populated areas you simply cannot have enough generation within the same footprint as the demand with existing tech.
I don't know if it's just because I've read about similar schemes for nearly a decade and so this story seems very boringly normal to me but...
The level of aggressive skepticism in some of these highly voted comments seem really out of proportion. Scary and cult-like even.
Vermont is stuck in the 19th century
Terrible article.
First, the 110 MW is wrong. It’s 53 MW of home batteries. Not that its the most important detail in this situation.
What is important in this context: Vermont already depends heavily on imported electricity and hydropower. The EIA says 73% of Vermont’s electricity is imported. Can we please acknowledge the stupidity of thinking you can replace generation with storage?
I could not find confirmation of how much battery capacity is actually available, but some simple math, based on an average load of 621 MW for Vermont, results in home batteries currently covering 14 minutes per day of power, meaning about 1% of daily needs.
I also found the real source of electricity used in Vermont: Hydro-Québec’s 28 large reservoirs contain about 176 million MWh of stored energy. This means the entirety of the stored energy at home is literally one million times less than what actual power plants can provide.
So, yeah, don’t turn off those power plants just yet, thinking you have “replaced them with home battery storage.”
And this is from someone who loves the idea of home battery storage and actually has my own small setup. Something being aspirational does not mean one should just spew misleading stuff like this.
> Can we please acknowledge the stupidity of thinking you can replace generation with storage?
Electricity consumption is not constant, just like generation isn't constant with some sources. You can certainly replace a number of peaker plants, e.g. gas turbines, with storage and reduce costs by a lot.
Yeah, peak shaving is a real thing, and it's actually a no-brainer, I think. I just got a bit annoyed and carried away because the article did not make clear how large a challenge it is to actually disconnect from the grid and stop relying on power plants.
The reason is that I have been dabbling with off-grid gear for fun. Nothing major, just a solar power station and a couple of solar panels. And here in Norway, you really get respect for how hard it is to get energy during the winter when there's no wind and no sun. Even if I had 100 kWh of battery storage and 20 kW of rated solar panel capacity, I would be dead in the water, at least for the entirety of December and January. The only viable solution for going full off-grid in Norway is a backup generator. You could get by with wind, maybe if you live in a predictable windy area and you have a large battery bank.
Since it's so cold and darker during the winter, I have always dreamed of someone making a really good Stirling engine for generating electricity. But there are way too few people living as far north as us, so there's really no demand. You don't have to go further south than Germany, and solar is fully viable on its own, even during the winter. And the entirety of the United States, with the exception of Alaska, is completely self-sustainable per household with just solar. But off-gridding one's own home is suffering the March of Nines problem, whereby it's exponentially more expensive to be grid-independent 99.99% of the time, and so forth.
I'm rambling now. Suffice it to say that I stand by the fact that the article is misleading, though the goal of off-gridding and getting as much solar and in-house storage as possible is something I wholeheartedly agree with. I don't like it when people don't communicate how large a challenge it is.
Wispr Flow is a dangerous tool It seems..... it makes it way too easy to write a lot of text.
It's amusing they carefully refrain from mentioning the battery manufacturer.
We are participants in this program. It's awesome.
For context, we are 3/4 miles from a paved road, and on our dirt road there are 6 homes. Like many houses in Vermont, we have a well instead of municipal water no power -> no water. Our house also came with a pellet stove that requires power in order to operate[0]. No power -> no heat. Ditto the propane boiler that runs domestic hot water and the baseboard radiators. Cell service is pretty sparse, and depending on your carrier you are wholly or mostly dependent on WiFi calling to report outages. Bit of a circular dependency there. There are lots of homes in VT like this.
The batteries are totally seamless. The only real indication that we're on battery is that anything without a crystal oscillator in it runs fast until the batteries are depleted enough that they could accept a charge from the solar panels we don't (yet) have[1]. The controller raises the line frequency to 66Hz when disconnected from the grid to let the inverters for the solar panels know that it can't/won't accept charge.
In practice this all plays out really well. We haven't yet had a winter outage that went on for more than a day since we moved. Last summer, however, we stained our home. The power comes in on the gable end, and we had Green Mountain Power disconnect it so we could sand and spray that part of the house without having live 240v power to work around on scaffolding 25' in the air. Running minimal lights, the fridge, the internet, the well pump, and either a couple of 5" sanders or a 60 gallon 240v compressor (for the spray gun), we got 4 days worth of uptime from the two battery packs. It was incredible.
The only downside to all of this is that the installation allowance wasn't enough to split my shop off from the backed-up panel[2]. I heat it with a heat pump (because insurance insurance companies get understandably twitchy about fuel-burning appliances in a wood shop). It draws a substantial amount of power when it's cold out, and if we lose power overnight and don't get awakened by the app notification, it's going to suck down a fair bit of power before the morning. The obvious workaround is to shut down the heat pump if there's bad weather in the forecast.
This probably isn't as much of a fringe case as it sounds. Anyone who heats with a heat pump is going to have to choose between not having heat or forgoing a lot of uptime.
[0] We will eventually replace it with a plain wood stove for resilience in the face of power outages.
[1] The ridge line of both the house and the shop runs north/south, so not ideal. The house has a dormer that precludes putting panels on half the roof, and skylights that preclude putting panels on another quarter of it. The shop needs to be re-roofed with metal and we need to have a couple of trees taken down before we can entertain putting panels on that roof. There have been higher priority projects over the last couple of years.
Meanwhile in Germany (facepalm) https://www.br.de/nachrichten/bayern/wenn-die-eigene-photovo...
Or they could use EVs. Require cars to have V2X (Vehicle to Grid, Vehicle to Load) feature. EV batteries are humongous.
As a consumer, would you want the extra usage on your battery? Those extra cycles have to cause some additional degradation to the system, but I do not know how much.
> As a consumer, would you want the extra usage on your battery?
I feel like this is likely going to be a non-issue in practice. Because these batteries are rated to last at least 10 years either way. And by that time, the cost of replacement will be dramatically cheaper.
> Because these batteries are rated to last at least 10 years either way
They are rated to last at least 10 years (under X usage conditions)
They won't last nearly that long under Y usage conditions if Y is substantially larger than X
They're rated to last that long under a full charge-discharge cycle per day. You won't be using them more than that unless you're doing something really crazy.
How much would I get paid?
Tesla Electric customers report making as much as $150 a day: https://electrek.co/2023/07/05/tesla-electric-customers-repo...
Car batteries are significantly larger than powerwall.
Net metering rates are pretty poor, so I would guess not much outside of extreme grid instability. Although, you then might want to selfishly hoard the juice for yourself.
It would not be selfish to run your home off the car battery during peak rates and therefore cutting peak demand on the grid. Everyone wins.
Depends on the nature of the agreement and the need for energy. In a load shedding event, the power company may want to cut useless residential consumers so as to prioritize hospitals. From a maximal good perspective, it is better that the hospital is running than I get to run my AC when the grid is straining.
Do any of the EVs sold in the US support Vehicle to Grid?
Many do - teslas, ford lightnings, Kia ev9, all the GM Ultium stuff (Silverado etc, hummer ev, Cadillacs), and a bunch of others.
Isn’t Tesla V2G just for Cybertruck?
Yes, but last I checked the bidi chargers were proprietary - tied to vehicle manufacturer - which is a huge disincentive. I don't want my home's battery connector locked into a vehicle brand/manufacturer.
Lightnings do (well before they were discontinued)
But given they are NMC chemistry, you probably wouldn't want to cycle them a lot for the grid (or just your home).
You wouldn't have to, to nevertheless provide great benefit to the grid. Look up "TOU billing".
Many do (assuming bidirectional charger), but it’s only 3.6kW max, in most cases
The down votes are because you use the word require. They’re never going to require it it would be opt in.
I think they mean to use EV batteries would require the EV to be designed for V2G capability, which is currently rare
Yes, thanks for the clarification. It goes without saying nobody can take energy from anyone without their permission. The manufacturers should build all cars with V2G feature, then people have the choice to participate in the energy ecosystem.
Nah, people want to wake up in the morning and know they can drive somewhere.
Requiring it is crazy.
In a hypothetical future where every single car participated, you probably wouldn't need to dedicate more than a few % capacity to still make an absolutely massive VPP
28% of trips are under a mile, 52% under three, 64% under five, 79% under ten, 93% under twenty-five, and 98% under 50 miles.
Only 0.8% of the trips are over 100 miles!
That infrastructure fee isn't going to go down despite your new capex (and opex) costs. Congratulations, everyone just got duped.
Sure it starts out covering edge cases but the more they realise they can shift a burden - and cost - to homeowners, it'll spread. I don't want grid infrastructure in my home personally
What happened to economies of scale?
It's more important for shareholders to increase profits than to actually invest in infrastructure.
Why would you put it in peoples homes and not at substations/next to residential transformers?
That is exactly right! Put the batteries where the cost of strain is the highest.
My belief is that this is ideologically/politically motivated. If you put the batteries next to network equipment it will not have the same immediate saving effect/user experience as the battery at home.
Battery at home gets a response of someone being happy about getting apiece of hardware, saving money and being renewable!
Vermont gets occasional ice storms or heavy snow that brings down trees on the power lines, so having a battery in your house can be pretty useful.
I'm a bit nostalgic for the nights when we'd break out the kerosene lanterns. But I concede that this might be more practical and a bit safer (a lot of VT houses are tinder boxes and good luck getting a good fire response in an ice storm).
Base power is doing something similar in Texas. AFAICT, they take a loss on the equipment, charge the batteries when electricity prices are cheap, then sell power out of the batteries when prices are high and keep the difference. The homeowner enjoys only most likely having backup power.
I mean, the electricity still has to be generated. That still costs money. This whole thing only works as long as there is someone willing to buy at the high prices and off peak demand stays low enough to keep prices cheap. Eventually there’s no more road to kick this can down.
> Eventually there’s no more road to kick this can down.
What do you mean? The opportunity for energy arbitrage will go away if energy prices are constant. Right now they aren’t, and I don’t really see how they would become constant based on the physics of producing and consuming energy.
Okay, well, that’s clever for now. The real arbitrage base is pulling is getting in while there’s capital to be raised for it and money to be extracted from the market, before competitors emerge and the incumbents respond and everyone realizes the play all along was to build an enormous battery plant without the expenses of land and compliance and negotiating with producers and carriers. They’re in the buying low phase now.
They’ll sell high when PE buys the company and pulls a Broadcom on all the existing customers, who will abandon the equipment after ten years go back to installing Tri-fuel generators while Centerpoint deals B2B with serious battery plant operators instead of B2C with annoying consumers
Customers running batteries they don’t own to store energy they can’t use for a company that won’t share profits is not the future.
Vermont’s project might be more viable, they’re a little better able to see beyond a spreadsheet up there. California will regulate it into unsustainable price territory. In the meantime finbros in Texas will make a killing having Claude build badass dashboards to show how much they make off bored suburbanites stuck on a grid built and operated as cheaply as possible to take as much money as they can before the useless state government is run out on a rail or finally eats the last bite of its own ass
Since you ask
I've seen a program funded by a utility that integrated batteries with air conditioners.
Note I have a Tesla powerwall at home. They installed it inside before I bought the house. I always wonder what happens when these things catch fire
> I always wonder what happens when these things catch fire
If you're hoping someone will chime in to tell you they have magic firefighting foam inside them or something, I regret to inform you that what happens if it catches fire is exactly what one might naively expect from large lithium batteries.
Yep. I'd never have a large battery like that in my house. Outside, a safe distance away, maybe.
Newer LiFePo4 (Lithium Iron Phosphate) batteries don't have the fire issues that the previous Lithium Ion generation did. They are a bit more expensive and heavier, but they are superior in every other way (safety, lifespan, max charge cycles).
They're actually cheaper than NMC and are the dominant chemistry.
Unless you plan to physically assault it with weapons, it’s extremely unlikely to catch fire.
Which version do you have? I believe they switched to LFP for V3, which should pose significantly less fire risk than the NMC chemistry they were using for V2 and before
A battery being tested: https://www.youtube.com/watch?v=WPTgg3joL5E
CATL: https://www.youtube.com/watch?v=WPTgg3joL5E
Vermont continues to be a leader in anarchism and distribution of power (pun intended).
Distributed power storage/generation has been a thing for a century and it’s finally economical enough to be mainstream.
This was the whole pitch of the solarcity/tesla solar tiles + power wall a decade or more ago.
That's a lot of spin. I didn't expect that from the BBC.
If they can claim "extreme weather" is why rural areas are finally getting their shit together, I can claim the decline of BBC is a sign of the times.
Really? You did not expect spin from the BBC? Odd. They barely ever report objectively on anything.
Batteries only store power, not produce it. Headline reads as misleading.
The headline says that the batteries are powering the homes, which is absolutely and technically correct use of "powering".
Maybe you saw "generating"? It may interest you to know that batteries output is counted among "generation" by the EIA and nearly all grid documents I know about, and is also technically correct.
Natural gas is merely stored solar energy too, if it the ideas of batteries "generating" anything rubs you the wrong way.
Too bad they’re seemingly Tesla batteries (from the picture). Like that self absorbed idiot needs even more money :(
I find it funny the article doesn’t mention Tesla once given these are all Tesla batteries and the picture is of a lady standing next to one. Great journalism, not biased or trying to steer the narrative at all.
I loathe Elon for probably the same reasons as yourself, but I can't deny Tesla's home battery systems are pretty well built.