Pretty neat! Time shifting renewable energy for later use
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.
Where I live in Canada, it's extremely unclear whether anyone is making their ROI on solar installations.
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!)
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.
> 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.
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.
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.
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.
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?
Most of the time, distribution charges are higher than the spot wholesale prices for import and export.
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.
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...
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.
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.
Seems like the former would have some development costs but ultimately be cheaper to manage
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
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.
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/...
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.
Turns out, they're on top of this.
https://cswd.net/cswd-in-the-news/vermont-expands-battery-re...
Source? Last time I checked a few years ago the prices were similar and lithium has dropped significantly since then.
https://offgridsolarguide.com/lead-acid-battery-brands-for-o...
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”.
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)
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.
The technology with PbS or even NiFe has existed for decades, but only took off with lithium.
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.
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)
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 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.
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.
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.
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.
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-...
Often people from different societies have difficulty understanding how anyone "could live like that" - in both directions.
God forbid we live in a world where sharing and helping others is OK.
I think there are better ways of sharing and helping.
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.
Actually it very literally does.
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.
> 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.
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.
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.
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 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 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.
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.
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.
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.
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.
Not saying this option would be better, we started this project way before batteries was a realistic option.
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.
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.
I thought it was a novel idea when I heard about it.
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 shouldnt be celebrated.
During peak need, renting some capacity from subscribers already on your grid means you don't need to build another peaker plant.
The 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 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.
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.
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.
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.
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.
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.
Not only do peaker plants make the most bucks/KWH, but they increase prices for all generation because of how auctions operate.
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.
What do you know about how the grid is operated anyway?
"Works for me, so must work for everybody."
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.
> 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?
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.
>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!?!?
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.
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.
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.
>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".
> 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.
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.)
The power walls can help to stabilize islands once they're back online, but they can't meaningfully participate in the initial phase.
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.
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.
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.
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.
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.
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.
The level of aggressive skepticism in some of these highly voted comments seem really out of proportion. Scary and cult-like even.
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.
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 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
Car batteries are significantly larger than powerwall.
But given they are NMC chemistry, you probably wouldn't want to cycle them a lot for the grid (or just your home).
Requiring it is crazy.
Only 0.8% of the trips are over 100 miles!
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.
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!
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).
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.
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.
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
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.
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.
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.
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.
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).
(the friend group is building them a pergola in their backyard next year to add more solar, Solarpunk "Amish barn raising" style, as one can never have too much solar)
[1] https://www.basepowercompany.com/ (no affiliation, I just like batteries!)
[2] https://nuclearbarbarian.github.io/IL-NLIC/index.html
> 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?
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/)