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EVs Are Essential Grid-Scale Storage

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Re: EVs Are Essential Grid-Scale Storage

#31

Post by Yizahi »

ramraj07 wrote: post #18
Yizahi wrote: post #10

Aren't people wary about using their very expensive car batteries for the grid? E.g. imagine you plug in your phone for the night, but instead of a single top up change it is now constantly discharging and charging again. Lifetime of pocket sized batteries is not too great even now, and in such scenario they will go bust 2-3 times faster, in year instead of 3 or so. Also discharge swings would be probably much bigger…

depends on how much the demand is. If all they have want is (collectively) a small drain (less than 1-2%) once or twice a day then why not? Especially if there are some incentives provided for the same.

I admit I don't know much about power grids, but I heard that they are structured in a lot of smaller zones, so if there is a local drop in the generation due to accident then probably only close EVs will be discharged, but by a lot, to compensate.

Re: EVs Are Essential Grid-Scale Storage

#32

Post by baq »

tboyd47 wrote: post #19

So not only do the batteries lose 2.3% capacity each year, and lose up to 40% of their range in cold weather, but now the power company wants to drain your car battery at night to power other people's homes. What a comedy of errors!

Au contrarie, it’s a solution to bring grid storage online to offset some wind and PV intermittency.

Re: EVs Are Essential Grid-Scale Storage

#33

Post by locallost »

Maxion wrote: post #13

Unless the $/kwh or lifecycle count of EV batteries change significantly, using them as a grid-scale storage is just not financially feasible. E.g. a NMC battery has a lifespan of around ~2000 cycles, a model S 90 D has a 90 kWh battery. That's around 180 MWh of total energy that can be moved through the battery before it is dead. On Reddit, a tesla user reports ( https://www.reddit.com/r/teslamotors/comments/v4dqkp/…

During most of last year prices in Europe were routinely over 300, 400 even occasionally over 1000 per MWh because there was an energy shortage. At the same time the prices can easily go negative if the conditions are favorable for renewables. It's not crazy to think that you would be paid to charge your car when there is an excess and then get paid a lot when there is a shortage. I don't know who would say no to this deal.

Re: EVs Are Essential Grid-Scale Storage

#34

Post by adrianN »

Maxion wrote: post #13

Unless the $/kwh or lifecycle count of EV batteries change significantly, using them as a grid-scale storage is just not financially feasible. E.g. a NMC battery has a lifespan of around ~2000 cycles, a model S 90 D has a 90 kWh battery. That's around 180 MWh of total energy that can be moved through the battery before it is dead. On Reddit, a tesla user reports ( https://www.reddit.com/r/teslamotors/comments/v4dqkp/…

It's not cheaper to run a natural gas power plant if you want to be carbon neutral. Then you have to run it with hydrogen, which is quite expensive to make. It also gets more expensive if you only want to run the gas plant a couple of hours per month because at all other times renewable power is sufficient.

Re: EVs Are Essential Grid-Scale Storage

#35

Post by raxxorraxor »

discordance wrote: post #4
raxxorraxor wrote: post #2

I don't understand the discrepancy between EV kWh and house battery kWh. Some cars have > 100 kWh capacity. Why do I pay > 1000$ per kWh for a house battery? At some point it is cheaper to just buy a car, even if you would never drive it. A Tesla Powerwall has 13 or so kWh? Why don't they use the car battery with nearly 10 times as much capacity? It is just unit prices that are far better for cars? Is the charge/disc…

$300/kWh for home storage is readily available. E.g. https://signaturesolar.com/eg4-ll-lithium-battery-24v-200ah/

True, there are better prices by now. But 5kWh? I thought my smartphone would have that by now...

Perhaps 200kWh is a bit exaggerated. And yes you also need a good quality inverter for your home that synchronizes with the net, but I actually don't believe this to be expensive high tech...

Ideally I wouldn't want to put the energy I generate with solar, wind or differently back into the power net. In my country you basically give that away for free. There are reasons for that, but the most efficient way would be to use the energy yourself as much as possible.

Sure, 5kWH is enough to soften peaks and there could already be huge benefit to this. But a bit more capacity would be really nice to really safe the energy of sunny days. Reminds me if disappointing USPs that let me play Tetris for an additional 7-8 minutes before I feel like civilization has broken down completely until power comes back.

Re: EVs Are Essential Grid-Scale Storage

#36

Post by [deleted] »

Yizahi wrote: post #10

Aren't people wary about using their very expensive car batteries for the grid? E.g. imagine you plug in your phone for the night, but instead of a single top up change it is now constantly discharging and charging again. Lifetime of pocket sized batteries is not too great even now, and in such scenario they will go bust 2-3 times faster, in year instead of 3 or so. Also discharge swings would be probably much bigger…

[deleted]

Re: EVs Are Essential Grid-Scale Storage

#37

Post by londons_explore »

Cthulhu_ wrote: post #9

Cool, but will the energy company pay for the wear and tear? Do you get paid extra if you promise to not use your car between hours X and Y?

The way most energy companies work, they do indeed 'pay for readiness' - ie. they'll give you money simply to be available to deliver power, even if you are never asked to deliver power.

That is also usually a market - ie. power stations can bid to provide that service, and the lowest bids are selected.

The only thing missing is that little residential guys usually aren't welcome to bid... Usually there is something like a 5MW minimum to play the game.

Re: EVs Are Essential Grid-Scale Storage

#38

Post by pornel »

Yizahi wrote: post #10

Aren't people wary about using their very expensive car batteries for the grid? E.g. imagine you plug in your phone for the night, but instead of a single top up change it is now constantly discharging and charging again. Lifetime of pocket sized batteries is not too great even now, and in such scenario they will go bust 2-3 times faster, in year instead of 3 or so. Also discharge swings would be probably much bigger…

Car batteries are not really comparable to cellphone batteries. Even among "lithium" batteries in cars there are multiple chemistries with different longevity and trade-offs (e.g. LFP can be kept charged at 100%, while NMC would rather not).

1. Cars have advanced battery management system with heating and cooling, which noticeably improves the battery life (e.g old Teslas have lost 1%-2% capacity per year over a decade, while Leaf about 3% per year, most likely due to lacking liquid cooling).

2. Cars won't let the battery discharge to 0%. Modern EVs even have an inaccessible reserve, so that when the car shows 0%, it's actually ~5%. Cars with vehicle-to-load/vehicle-to-grid typically stop giving power at 20% state of charge. Slowly cycling around 50% is quite gentle for the battery.

3. The grid just has to pay more for the storage than the cost of battery wear. The "duck curve" means they'll want to pay you to take electricity off of them at noon, and pay you a premium to get it back in the evening peak time.

Re: EVs Are Essential Grid-Scale Storage

#39

Post by mhandley »

locallost wrote: post #33
Maxion wrote: post #13

Unless the $/kwh or lifecycle count of EV batteries change significantly, using them as a grid-scale storage is just not financially feasible. E.g. a NMC battery has a lifespan of around ~2000 cycles, a model S 90 D has a 90 kWh battery. That's around 180 MWh of total energy that can be moved through the battery before it is dead. On Reddit, a tesla user reports ( https://www.reddit.com/r/teslamotors/comments/v4dqkp/…

During most of last year prices in Europe were routinely over 300, 400 even occasionally over 1000 per MWh because there was an energy shortage. At the same time the prices can easily go negative if the conditions are favorable for renewables. It's not crazy to think that you would be paid to charge your car when there is an excess and then get paid a lot when there is a shortage. I don't know who would say no to thi…

Of course at some point in the future if a lot of people with EVs say yes to this deal, the price range will narrow significantly, and eventually stabilize to the point where it's only just profitable given battery degradation costs. But it may take a long time to get to that stage.

Re: EVs Are Essential Grid-Scale Storage

#40

Post by schiffern »

Yizahi wrote: post #10

Aren't people wary about using their very expensive car batteries for the grid? E.g. imagine you plug in your phone for the night, but instead of a single top up change it is now constantly discharging and charging again. Lifetime of pocket sized batteries is not too great even now, and in such scenario they will go bust 2-3 times faster, in year instead of 3 or so. Also discharge swings would be probably much bigger…

> instead of a single top up change it is now constantly discharging and charging

This is where V1G beats V2G.

V1G (AKA grid-adaptive charging) just chooses when to charge the car, to efficiently spread out the grid load overnight and spatially across the network. No extra charge cycles, in fact it's probably more mild than just charging at full speed.

The key is that you need a UI setting for "Immediately charge to X%" and "Charge to Y% by Z:00." This avoids the problem where you find yourself without enough charge to get to work (or the local hospital).

> you will now see multiple 0%-100% charge cycles daily.

Even for V2G, why wouldn't there be a depth of discharge slider?

> if its lifetime will be shortened... then electric company need to compensate owners

Or better yet, owners set their car to only "bid" for a grid storage job when the cost-per-kWh is greater than the cost of degradation.

This should be the default after enabling V2G.

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