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EVs Are Essential Grid-Scale Storage

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Re: EVs Are Essential Grid-Scale Storage

#21

Post by Maxion »

VadimPR wrote: post #16
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/…

Does the cost of the natural gas power plant include the green house gas costs it is emitting?

There are many estimates for the generation cost on wikipedia, at least the IPCC one does not try to estimate what the costs of the emissions would be.

And the price of the battery does obviously not include the generation costs of the energy needed to charge it, any charging/discharging losses, nor the infrastructure costs of a V2G setup.

So it's a very simplistic and incomplete comparison that gives a rosier picture of V2G MWh price than reality would.

Re: EVs Are Essential Grid-Scale Storage

#22

Post by Isinlor »

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…

Tesla is supply limited, so they can put prices high. That's probably about it.

Re: EVs Are Essential Grid-Scale Storage

#23

Post by causi »

Even if you completely do away with concerns of battery wear, I'd only be willing to participate in this as long as my household still had an ICE vehicle to fall back on. When I get home and plug the car in I don't want to have to think about whether I might want or need to leave the house at a particular time with a particular charge; I just want the charge to be as high as possible as soon as possible.

Re: EVs Are Essential Grid-Scale Storage

#24

Post by rbanffy »

manholio wrote: post #11

This is never going to happen at scale. Energy is fungible: one cannot compete on "quality" of energy, just on price, a kWh is a kWh and the provider with the cheapest energy will always win in the marketplace. So this means any EV owner looking to make a profit is competing against large scale industrial storage entities that: - have large mass and purchasing power, optimizing their battery purchasing and operationa…

> Energy is fungible: one cannot compete on "quality" of energy, just on price

It is fungible, but prices can vary according to limitations on supply. If the big company's capacity is maxed out and demand continues to increase, energy already acquired at lower cost and stored in the car can be sold for profit.

Re: EVs Are Essential Grid-Scale Storage

#25

Post by londons_explore »

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…

Luckily, any degradation can all be predicted ahead of time.

A 60kwh car battery might cost $10k, and allow 2000 charge cycles. So each kwh cycled into and out of the battery costs 8 cents.

So a smart algorithm can decide it's worth draining the battery back into the grid if the profit to be made is more than 8 cents.

Buuuut... Delaying charging till later is free. So another car owner's car might see on the futures market that delaying charging starting from 6pm till 11pm might save a few cents.

Obviously that means it's most economically efficient for every owner to do grid balancing merely by smartly delaying charges - and in turn price fluctuations will rarely exceed 8 cents.

The component that is missing to make this happen is cars which have code to automate this process, and markets in place that have API's to let the car buy and sell energy, and futures in energy, by the kwh. Users need not understand how it works - they just tick the tickbox which says 'charge and discharge smartly to minimize electricity costs'.

Today, those markets are typically only open to big players, cars don't have a tickbox, and wall chargers typically won't let a car put power into the grid.

Re: EVs Are Essential Grid-Scale Storage

#26

Post by dtech »

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/…

$0.11/KwH is super doable. Keep in mind that discharging is only necessary and profitable during peak demand, when prices are much higher than that. $0.50/KwH is far from uncommon. E.g. today energy peaks at €0.28/KwH in my area. It dipped at €0.17 so it would've already broke even.

Re: EVs Are Essential Grid-Scale Storage

#27

Post by londons_explore »

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/…

Battery lifespan in 'cycles' is kinda simplifying things too much.

Most batteries, if charged and discharged slowly, in the right temperature range, and while keeping the charge between 40 and 60% capacity, get far higher lifetime than the advertised 'cycles' number.

The damage and degradation happens mostly near 0%, near 100%, when charging/discharging fast, and when excessively cold or hot.

Cell balancing becomes less important when you're not nearly full or empty, and balancing wastes quite a lot of energy - making the battery more efficient when used between 40-60% too.

Re: EVs Are Essential Grid-Scale Storage

#28

Post by locallost »

It's a well known fact that cars stay parked for over 90% of the time, so this idea has been floating around for a while. The wear and tear issue is only a concern if nothing changes in the way we currently charge for electricity, e.g. a fixed price that gets adjusted from time to time. But I don't think we will -- even today we have more and more providers that charge with prices fluctuating hourly to reflect wholesale market prices. Thus if you can charge dirt cheap and sell it later for a large multiple more, you have a big incentive to do that. With the rise of renewables that basically looks unstoppable this will become a reality a lot quicker than I think a lot of people anticipate.

Re: EVs Are Essential Grid-Scale Storage

#29

Post by manholio »

rbanffy wrote: post #24
manholio wrote: post #11

This is never going to happen at scale. Energy is fungible: one cannot compete on "quality" of energy, just on price, a kWh is a kWh and the provider with the cheapest energy will always win in the marketplace. So this means any EV owner looking to make a profit is competing against large scale industrial storage entities that: - have large mass and purchasing power, optimizing their battery purchasing and operationa…

> Energy is fungible: one cannot compete on "quality" of energy, just on price It is fungible, but prices can vary according to limitations on supply. If the big company's capacity is maxed out and demand continues to increase, energy already acquired at lower cost and stored in the car can be sold for profit.

But if that limitation is repetitive to the point of investing in infrastructure to use EVs, then some other large-scale investor will close that arbitrage opportunity.

Basically, the next-day / week energy markets, where EV owners can compete, will be saturated by grid-scale battery operators. Renewables will leave large gaps for seasonal energy needs - for example two weeks of winter with no sun and no wind - but EVs cannot help there. So some spin on-demand non-renewables will need to cover that (i.e., the current main providers, after becoming too expensive to run due to carbon pricing).

Re: EVs Are Essential Grid-Scale Storage

#30

Post by londons_explore »

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/…

> 106 USD per MWh hour, which is more than most generation sources

Minute by minute electricity prices vary really widely. It isn't unusual for prices to spike up 10x briefly at peak times.

Most power stations have too high a capital cost to only run 2% of the time... whereas your tesla battery has no capital cost, so using it to power the grid 2% of the time when the prices are sky-high is very attractive.

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