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Can “second life” EV batteries work as grid-scale energy storage?

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Re: Can “second life” EV batteries work as grid-scale energy storage?

#61

Post by noosphr »

epistasis wrote: post #51
noosphr wrote: post #46

Earlier quoted context omitted.

The low energy future that was envisioned is not happening. The AI arms race, which has become an actual arms race in the war in Ukraine, needs endless energy all times a day. China is already winning the AI cold war because it adds more capacity to its grid a year than Germany has in a century. If we keep going with agrarian methods of energy production don't be surprised that we suffer the same fate as the agrarian…

You have that exactly backwards: solar + storage is what will give us energy abundance at less money than we could ever imagine from nuclear fission or fusion. China is winning the AI Cold war because it's adding solar, storage, and wind at orders of magnitude more than nuclear. I'm not sure who's doing your supposed "envisioning" but there is no vision for cheap abundant energy from fusion. Solar and storage deliver…

China has been building out nuclear capacity at 5% a year for 25 years.

Solar and wind capacity had shot through the roof in the last five years because they can't sell hardware to the west any more.

The other big item is hydro power, which China has a ton of untapped potential for. Unfortunately for the West every good river has already been damed so we can't follow them there.

Re: Can “second life” EV batteries work as grid-scale energy storage?

#62

Post by ramses0 »

benzible wrote: post #21
dylan604 wrote: post #9

Without being a battery chemistry expert, why do these battery packs become not useful for an EV yet could still be useful for energy storage. They keep saying that 80% of life becomes unusable for EV, but that's still a lot of life. Is it that grid energy is more of a constant drain while the EV is lots of hard pulls (for lack of better wording)? In an EV, the battery cannot provide the higher volts being requested…

It's not just about capacity (80% is still a lot), it's that degraded batteries lose their ability to deliver high current under load—so acceleration suffers and voltage sags under hard pulls. For grid storage, you're doing slow, steady charge/discharge cycles over hours, so the same battery that can't handle aggressive driving anymore works perfectly fine. Plus, grid storage has virtually unlimited space and no rang…

Looking forward to the grid-scale warehouse fire of battery packs popping off...

Re: Can “second life” EV batteries work as grid-scale energy storage?

#63

Post by dylan604 »

ramses0 wrote: post #62
benzible wrote: post #21

Earlier quoted context omitted.

It's not just about capacity (80% is still a lot), it's that degraded batteries lose their ability to deliver high current under load—so acceleration suffers and voltage sags under hard pulls. For grid storage, you're doing slow, steady charge/discharge cycles over hours, so the same battery that can't handle aggressive driving anymore works perfectly fine. Plus, grid storage has virtually unlimited space and no rang…

Looking forward to the grid-scale warehouse fire of battery packs popping off...

They claim to have taken the Moss Landing fire into account with how they are placing their batteries. We won't know if they've really solved the problem or not until their first battery pack experiences a runaway thermal event.

Re: Can “second life” EV batteries work as grid-scale energy storage?

#64

Post by torginus »

irons wrote: post #44
torginus wrote: post #31

Personally speaking, having just bought an Ioniq 5 and installing solar at home what I see as the near future improvement is adding V2L functionality, which I can hook up to the generator input of my solar inverter, essentially adding another 60kWh buffer to my grid storage. Considering how expensive residential batteries are and how quickly EVs depreciate, I think soon it'll be cheaper to get a used EV as a cheap so…

In the US, V2L limits your ability to output power from the car to about 1500 W. It's not going to power your house as more than a stopgap, even if you do have supplementary house batteries. V2H/V2G justify their complexity by solving that problem, along with all the ancillary grid benefits.

Not sure if that's the case - however doing V2L requires the manufacturer to add an inverter to the car, and making that powerful probably adds extra cost most customers wouldn't pay. TI just looked it up and my Ioniq can only do about 2kW sustained - but since this charges the house battery, that's enough - idle load is just a couple hundred watts.

Re: Can “second life” EV batteries work as grid-scale energy storage?

#65

Post by Dylan16807 »

epistasis wrote: post #27
JohnLocke4 wrote: post #19

Earlier quoted context omitted.

In 2040 fusion energy advancements will have gotten far enough to be the next technological step and make this redundant anyway

There's currently no technological path for fusion to be cheaper than fission. It would require a technological breakthrough that we have not yet imagined. And already, solar plus storage is cheaper than new nuclear. And solar and storage are getting cheaper at a tremendous rate. It's hard to imagine a scenario where fusion could ever catch up to solar and storage technology. It may be useful in places with poor sola…

Fission is expensive for regulation reasons more than technological reasons, so if fusion doesn't face the same barriers then it could be cheaper than fission.

But I agree that it doesn't look like fusion is going to be cheap any time soon.

Re: Can “second life” EV batteries work as grid-scale energy storage?

#67

Post by epistasis »

noosphr wrote: post #61
epistasis wrote: post #51

Earlier quoted context omitted.

You have that exactly backwards: solar + storage is what will give us energy abundance at less money than we could ever imagine from nuclear fission or fusion. China is winning the AI Cold war because it's adding solar, storage, and wind at orders of magnitude more than nuclear. I'm not sure who's doing your supposed "envisioning" but there is no vision for cheap abundant energy from fusion. Solar and storage deliver…

China has been building out nuclear capacity at 5% a year for 25 years. Solar and wind capacity had shot through the roof in the last five years because they can't sell hardware to the west any more. The other big item is hydro power, which China has a ton of untapped potential for. Unfortunately for the West every good river has already been damed so we can't follow them there.

> Solar and wind capacity had shot through the roof in the last five years because they can't sell hardware to the west any more.

"can't sell hardware??" hah! I've never heard that weird made-up justification, where did you pick it up from?

China installed 277GW of solar in 2024, capacity factor corrected that's 55.4 GW of solar power. That's equivalent to the entire amount of nuclear that China has ever built. One year versus all time. And then in the first half of 2025, China installed another 212GW of solar. In six months.

Nuclear is a footnote compared to the planned deployment of solar and wind and storage in China.

Anybody who's serious about energy is deploying massive amounts of solar, storage, and some wind. Some people that are slow to adapt are still building gas or coal, but these will be stranded assets far before their end of life. Nuclear fusion and fission are meme technologies, unable to compete with the scale and scope that batteries and solar deliver every day. This mismatch grows by the month.

Re: Can “second life” EV batteries work as grid-scale energy storage?

#68

Post by archi42 »

torginus wrote: post #31

Personally speaking, having just bought an Ioniq 5 and installing solar at home what I see as the near future improvement is adding V2L functionality, which I can hook up to the generator input of my solar inverter, essentially adding another 60kWh buffer to my grid storage. Considering how expensive residential batteries are and how quickly EVs depreciate, I think soon it'll be cheaper to get a used EV as a cheap so…

Residential batteries are not that expensive anymore, at least not all of them. That's a misconception I also held until a few years ago ;-)

My first 14.3 kWh pack cost about 2800$ DDP from China, delivered 03/2023. For that one I did calculate how long it took for amortization, which I projected at about 5 years.

The second, identical pack was delivered 08/2024 and cost 2000$ DDP. Since we got an EV that's drawing about 14kWh per day, I didn't bother doing the math and just ordered it.

These are 280Ah 16S 51.6V packs, based on the EVE LF280K. In an enclosure, with a BMS (Seplos, 200A) and a dedicated balancer. They are good for 6000 cycles at 140A or less [each]. Mind these were both part of small bulk orders - I think each time we ordered 6 to 8 of these, which reduced shipping costs.

Re: Can “second life” EV batteries work as grid-scale energy storage?

#69

Post by torginus »

kieranmaine wrote: post #54
torginus wrote: post #31

Personally speaking, having just bought an Ioniq 5 and installing solar at home what I see as the near future improvement is adding V2L functionality, which I can hook up to the generator input of my solar inverter, essentially adding another 60kWh buffer to my grid storage. Considering how expensive residential batteries are and how quickly EVs depreciate, I think soon it'll be cheaper to get a used EV as a cheap so…

Very interesting - I did not know this was possible. A few questions: 1. Does the solar inverter do away with the need for a V2G or V2H unit? 2. What are the limitations vs a dedicated V2G/H unit? 3. Is generator input on your solar inverter a common feature across inverters?

1. It does. The only issue is that the car can only output about 2kW sustained (this is a model limitation). That's fine since I have batteries in the house.

2. Tbh not super familiar with V2G/V2H, other than it being super expensive for both the wall box and the car (only high end models tend to support it)/

3. No idea, but it's not a high end feature, I wouldn't count on any inverter to just have it, but if you're looking to buy one that does, I don't think you'll be breaking the bank.

Imo the future is for solar inverters to offer a dedicated DC car charger port, as once again all the hardware is already in there.

Re: Can “second life” EV batteries work as grid-scale energy storage?

#70

Post by [deleted] »

Dylan16807 wrote: post #65
epistasis wrote: post #27

Earlier quoted context omitted.

There's currently no technological path for fusion to be cheaper than fission. It would require a technological breakthrough that we have not yet imagined. And already, solar plus storage is cheaper than new nuclear. And solar and storage are getting cheaper at a tremendous rate. It's hard to imagine a scenario where fusion could ever catch up to solar and storage technology. It may be useful in places with poor sola…

Fission is expensive for regulation reasons more than technological reasons, so if fusion doesn't face the same barriers then it could be cheaper than fission. But I agree that it doesn't look like fusion is going to be cheap any time soon.

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