Used Waymo robotaxi batteries become backup storage for power grids
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Considering the apparently limited benefits of Waymo vehicles, maybe it would make more sense to skip the middleman and just install new batteries in grid-scale backups?
I very much like the concept of a circular economy but I like the idea of less wasteful systems even more.
I very much like the concept of a circular economy but I like the idea of less wasteful systems even more.
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From information I've seen, reusing car batteries for storage is less about the degradation of capacity in the batteries, and more about the ability for them to take and supply the current at the level the car demands. Storage has lower peaks, so the demand is still well within the capability of the battery.
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Beat me to it - was going to chime in to point out exactly this.
Also the that fact that the overall capacity, individually, will have fallen off a bit - perhaps insufficient for vehicle use, but in a system of banks and working through averages, its less of a problem.
At least they're not ending up in landfills and at least more and more thought is going into the question of "what are we going to do with all these batteries?".
The more they can be recycled, refurbished and/or repurposed, the better it is overall.
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I'm glad to hear that a setup like this is operational already. It's always been discussed as something that will happen, but I was worried there might be barriers. If they've already deployed 4k used batteries, that's fantastic news and indicates that this could scale.
This kind of reuse is not a silver bullet, but I expect it will be a growing part of the solution to the intermittency of most renewable power.
This kind of reuse is not a silver bullet, but I expect it will be a growing part of the solution to the intermittency of most renewable power.
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How did you make that conclusion from an article reporting the entirely reasonable finding that robo-taxis operate similarly to other non-robotic taxis?
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Exactly. Waymos make traffic worse. Regular taxis also make traffic worse. Me driving to the hardware store makes traffic worse. You driving to work makes traffic worse. All cars make traffic worse, except arguably for carpool and transit vehicles.
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I definitely agree with the notion we should just install more grid-scale batteries. However, I think these types of Lithium-Ion batteries would be better suited in cars, given their particular strengths of high-volume discharge (please, someone correct me if I'm wrong
).From the stories I've read here on Ars we should probably be looking at Sodium-Ion or Vanadium-Redox flow batteries.
Regardless, if we're going to use them anyway, can't think of a better use-case than this! Keep the battery working until it's finally mostly spent, then recycle the whole thing and start over. Then we'll finally hit the true circular economy for these types of batteries.
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Their second life use is exactly what we were told it would be. Ignore the threatened-industry lies about them filling our landfills. Batteries are set to become valuable commodities. After this secondary use, they then will be recycled into new, valuable batteries.
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The photo of the SEPV Sierra facility shows the batteries in outdoor "sheds", which suggests the biggest problem of the Vistra Energy fire (storing all the batteries inside one building) doesn't apply to B2U's design
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This is great.
My relative just got quoted $20k to add a single 10kwh battery backup to their home. Meanwhile a used Tesla can cost about the same, and contains more than 80kwh. It's really a shame that most EVs don't support V2H when teardowns have repeatedly shown that it just takes $10 worth of parts and some software.
My relative just got quoted $20k to add a single 10kwh battery backup to their home. Meanwhile a used Tesla can cost about the same, and contains more than 80kwh. It's really a shame that most EVs don't support V2H when teardowns have repeatedly shown that it just takes $10 worth of parts and some software.
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Indeed, this makes me more curious what waymo's threshold is for replacing or decommissioning a battery. Taxiing seems relatively easy for cars; they're not hauling heavy loads or doing quick acceleration runs or anything else that really stresses a battery (aside from maybe fast-charging).
Even if your capacity was limited to an extreme 50%, it seems like that car would simply not pick up a fare if the distance was out of range.
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In my experience, a phone battery that's reporting 81% original capacity might as well be broken.
You'd think it would be almost new (only missing 19% capacity, right?) but it's actually horrible.
Are car batteries different?
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Thousands evacuated around leaking Orange County chemical tank: ‘It fails, or it blows up’ (03/21/2026, LA Times)
LyondellBasell plant fire in Pasadena burned over 20,000 pounds of gases after flare system mishap (03/13/2026, Houston Chronicle)
Fire at Valero refinery in Port Arthur extinguished; shelter-in-place lifted, some schools delayed (03/24/2026, 12 News Now)
List of oil spills (Wikipedia)
It is a significant editorial miss not to include a discussion around whether lessons learned from the near daily fossil fuel incidents had made their way into design and response planning for every single fossil fuel project. What were [sic] left with is tepid cover for the fossil fuel industry's hundred-plus years of environmental destruction and degradation.
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Inventory and Supply can be different things. The deal with Waymo would be ~ 3.5 GWh all by itself but those aren't in inventory until they get pulled from the cars.
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Both my state and the one that tries to call itself the "Great State" do some pretty dumb things--exactly which ones are considered can be a topic for a different thread--but it is encouraging to see these two influential and vital parts of our country partnering on a project that is not only positive and useful, but sends a not-so-subtle "You're an idiot" message regarding this administration's energy policies.
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The usual industry figure from the reuse companies is about 80% capacity.
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Actually I think you’re probably correct; their website is pretty vague, but from the Wayback machine it looks as though there’s no mention of 4GWh of supply prior to this announcement. I’m still a bit concerned about their ability to suddenly scale by a factor of 50 times, but that’s a much more positive read on the situation.
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Okay, to be clear, up front, this is a cool way to deal with old batteries.
But in reading this, and thinking about "green" tech, and science fiction, and how these batteries will likely be used to feed the electrical needs of other EV's to keep them alive, I couldn't help but think of some overly curious Waymo wandering into one of these battery farms and seeing them and delivering its own horrified version of Charleston Heston's Soylent Green line about how their food is Waymos.
Still a cool concept as long as people aren't part of that food chain.
But in reading this, and thinking about "green" tech, and science fiction, and how these batteries will likely be used to feed the electrical needs of other EV's to keep them alive, I couldn't help but think of some overly curious Waymo wandering into one of these battery farms and seeing them and delivering its own horrified version of Charleston Heston's Soylent Green line about how their food is Waymos.
Still a cool concept as long as people aren't part of that food chain.
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That is terrible it's a good thing the alternative fossil fuel industry never has multi day uncontrolled fires spewing toxins into the environment...
Get a fucking grip.
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Let's go there with hydrocarbons, shall we?
https://en.wikipedia.org/wiki/List_of_natural_gas_and_oil_production_accidents_in_the_United_States
Have fun scrolling. And scrolling.
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Holding this up against the other Robo taxi operator in Austin, I am not sure why anybody thinks the other folks have a chance at all.
Instead of vaporware promises/ announcement they’ve actually got a plan to do Something and they shared it with people. More like this, please.
Instead of vaporware promises/ announcement they’ve actually got a plan to do Something and they shared it with people. More like this, please.
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Phone batteries have to be able to sustain a certain amount of voltage output for a certain amount of time in order to run the device.
When you tie a bunch of batteries together, the picture changes. Even degraded cells can contribute, and although it is a suboptimal arrangement, it’s a great way to extend the use of battery pack that are difficult and troublesome to manufacture from new.
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I recently came across a document from Cal ISO reporting they had to curtail 1,460 GWh of renewable electricity for the month of Apr26, meaning it was wasted. That's about as much energy as Diablo Canyon produces in a month. Or almost 50 GWh a day, about two hours of California's average demand.
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That seems high for one backup battery. I scouted the price for 2, and it was around $23,000 installed. Fortunately my power company offered a 10 year lease for $6500 installed. Check for incentives. Get a second quote.
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This is standard first-pass disposal of EV batteries nowadays. Waymo got a press release, not a plan.
For a context filler, various battery recycling companies found out in the last few years that traction batteries have plenty of life left in them, and service in a storage plant is the kind of light duty (low C factors) that it's basically retirement in happy acres. They've still got plans to render the stuff down to goop eventually, but before that they can get years of useful, profitable service.
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I think Toyota had a similar program but a lot smaller in scale. A ranch in Yellowstone's Lamar Buffalo Ranch. They created back-up for the ranch using used hybrid batteries.
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My phone battery ( i phone) is reporting 74 % just now. I notice a bit of more frequent charging, but it is still running nicely the whole day long.
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BEVs, especially used BEVs, are definitely the cheapest way to get a lot of battery capacity but I doubt you can add V2H support for $10 worth of parts unless you assume you already have an inverter capable of powering the house or are ignoring that cost. That 20k quote presumably includes an inverter like that and probably a bunch of other things like electrical work in the house that would still be needed even with a BEV providing the battery storage. A bit of an unfair comparison really.
In a perfect world I'd have a small home battery that would work with my solar both to cover power outages and maximize the benefit of my solar generation and would be able to plug into my two BEVs for additional storage for extended outages. Unfortunately, the standards aren't really there yet to support that so the only solutions currently are proprietary ones.
It probably depends on the situation. For the early Leaf's and other similar BEVs the range loss is a factor. When you start off with 100 miles of range on a good day loosing 20% of that definitely impacts the usefulness of the BEV. For BEVs with a nominal starting range of 200+ or 300+ miles the range loss is probably less of a factor as 160+ or 240+ miles of range is still pretty usable. For something like Waymo specifically the range loss might be more impactful because they are driving around so much. For your typical personal usage there's probably 0 difference between 160 miles of range on a BEV or 300+. If your daily driving is typically 50 miles or less and you can plug it in and charge every night or every couple days you've got plenty of range to cover your driving every day. If a Waymo is averaging 200 miles a day because it's in operation all day and driving not just from point to point for the ride it's providing but also from one drop off to the next pick up location then that 160 mile range BEV is now no longer covering it's daily usage and needs to charge up at some point during the day.
I think this makes lots of sense. A battery pack that is no longer useful for a BEV still has plenty of capacity to be useful for a grid storage location. Even a 24kWh Leaf pack at half health which would be 40ish miles of range would be 10+ kWh of usable storage for a grid application which is definitely useful. There's a company offering 3rd party battery replacements for Leaf's and they also offer a kit to reuse the cells from your old battery for home storage.
https://vivnevs.com/products/vivne-...orage-solution-without-cells?VariantsId=12933
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Then use NEC/NFPA to enforce safe designs. Encourage chemistries that aren't prone to electrolyte fires. Require battery packs be installed in a container that supports immersion, plus enough enough on-site water to handle evaporation for however long it takes to fully dissipate.
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