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EVs Are Essential Grid-Scale Storage

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Re: EVs Are Essential Grid-Scale Storage

#191

Post by tzs »

londons_explore wrote: post #25
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…

> A 60kwh car battery might cost $10k, and allow 2000 charge cycles

After those 2000 cycles is the battery completely dead, or does it still work but at a reduced capacity?

If it does still work at a reduced capacity, does continued use reduce the capacity to 0 after a while, or does is plateau at some fixed reduced capacity and stop further degrading?

Re: EVs Are Essential Grid-Scale Storage

#192

Post by jacquesm »

trashtester wrote: post #46
londons_explore wrote: post #25

Earlier quoted context omitted.

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…

> Buuuut... Delaying charging till later is free. This functionality is already there. > So each kwh cycled into and out of the battery costs 8 cents. This is quite much. If you add other infra overhead, feeding power back into the grid is not going to produce much revenue for the individual unless the selling price is maybe 20 cents above the price when charging. On the other hand, something that MAY make more sense…

For a blackout situation your car won't be of much help: any inverter that is grid tied will refuse to come on as long as there isn't a low impedance functioning grid connection present. Typically they'll measure the conditions for a minute or two, then make the connection (you'll hear a relay trip) and then bit by bit the inverter starts pushing power by advancing its on phase relative to the grid. If that doesn't stay within very precise parameters it will switch off, wait for a bit and try again.

So you can forget about your car (or even most solar inverters) to work during blackouts unless a couple of things are present:

- a automatic grid disconnection switch (aka a transfer switch)

- special firmware to allow the inverter to operate in 'off grid' mode

Both Xantrex and Victron have inverters that can do this but they are not normally deployed for such installations and they wouldn't know what to do with your car battery (voltage much higher than the ones that they require, typically 48V max).

Growatt has some off-grid units too, but those still won't satisfy the impedance requirements of your cars inverter (the grid is 'too small' so it will fluctuate too much due to high impedance).

Re: EVs Are Essential Grid-Scale Storage

#193

Post by philipkglass »

sokoloff wrote: post #176
iso1210 wrote: post #81

Earlier quoted context omitted.

This does work today at grid scale, people use their home batteries (either on wheels or not) to charge/discharge to the grid in the UK all the time. If someone builds that storage facility to do it commercially then great. > rooftop solar can't exist without special subsidies Yet it does

There are special subsidies for rooftop solar here in the US (Solar Investment Tax Credit). Are there not subsidies for solar where you live? https://www.seia.org/initiatives/solar-investment-tax-credit... > The solar Investment Tax Credit (ITC) is one of the most important federal policy mechanisms to support the growth of solar energy in the United States. Since the ITC was enacted in 2006, the U.S. solar industry…

The same link says:

The Section 48 commercial credit can be applied to both customer-sited commercial solar systems and large-scale utility solar farms. The rate is effectively at 30% until Treasury issues guidance on new wage and apprenticeship standards. Two months later, the rate will be at 6%, with an additional 24% (for a total of 30%) available for meeting these new labor standards.

So utility-scale solar farms can get the same 30% credit as rooftop solar. They're both tax-advantaged compared to (e.g.) building a new gas plant, but the rooftop credit isn't any higher, at least not on the federal level. Self-consumption from rooftop solar may avoid other taxes, like sales tax, but in many states there is no sales tax on residential electricity to begin with.

Re: EVs Are Essential Grid-Scale Storage

#194

Post by mnw21cam »

tuatoru wrote: post #155
danuker wrote: post #44

Earlier quoted context omitted.

It worries me that if industrial-purpose batteries cost the same and have similar degradation, grid services will also decide not to charge/discharge if the profit is less than 8 cents. This tells me that Li-Ion batteries are far from the ideal medium for grid storage.

There are various niches in grid storage. Li-ion are good for frequency stabilisation: initial response times of the order of ten milliseconds, run times up to several tens of minutes maybe. For longer durations, flow batteries and other chemistries are probably better. They win because of very good cycle life and calendar life (20_000 cycles, 50 years) but tend to take longer to start up. Flow batteries include vana…

These up and coming battery types look fantastic, but everyone seems to forget that lead-acid batteries are already way better than Li-ion or LiFePo for non-mobile energy storage, in terms of price per kWh stored.

Re: EVs Are Essential Grid-Scale Storage

#195

Post by mnw21cam »

nickelcitymario wrote: post #77
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…

The way I read it, the paper is more interested in what happens to EV batteries when they drop to 80% of the maximum storage capacity. If I understood them, they're saying that at this level, the battery is no longer suitable for transportation purposes. So what do you do with the old battery when you replace it? They're suggesting using these extremely expensive but no-long brand-new batteries for additional grid st…

The reason they use the 80% mark is that Li-ion batteries tend to rapidly degrade after they reach that point, so once they get there it's best to replace them.

Re: EVs Are Essential Grid-Scale Storage

#196

Post by ccheney »

jononomo wrote: post #121

When the Ford F-150 Lightning came out I was interested to learn that the battery was powerful enough to power a standard American house for over two days. This made me wonder why new houses don't come with a battery built in, thereby making power outages obsolete. A battery that could withstand a 48-hour power outage without the occupants even realizing anything had happened seems like it would give the power grid a…

I'm curious to see what comes of V2G tech and other home battery systems. I know that Panasonic[1] & Enphase[2] have their own systems rolling out. Adding these systems to new home builds makes a lot of sense to me in the interest of future-proofing.

Here's an interesting example where a new housing development in Las Vegas built all the houses with battery storage as well as solar generation for the entire neighborhood[3]

[1] https://na.panasonic.com/us/energy-solutions/battery-storage...

[2] https://enphase.com/store/storage/iq-battery-10

[3] https://electrek.co/2022/12/08/tesla-neighborhood-launches-p...

Re: EVs Are Essential Grid-Scale Storage

#198

Post by sokoloff »

philipkglass wrote: post #193
sokoloff wrote: post #176

Earlier quoted context omitted.

There are special subsidies for rooftop solar here in the US (Solar Investment Tax Credit). Are there not subsidies for solar where you live? https://www.seia.org/initiatives/solar-investment-tax-credit... > The solar Investment Tax Credit (ITC) is one of the most important federal policy mechanisms to support the growth of solar energy in the United States. Since the ITC was enacted in 2006, the U.S. solar industry…

The same link says: The Section 48 commercial credit can be applied to both customer-sited commercial solar systems and large-scale utility solar farms. The rate is effectively at 30% until Treasury issues guidance on new wage and apprenticeship standards. Two months later, the rate will be at 6%, with an additional 24% (for a total of 30%) available for meeting these new labor standards. So utility-scale solar farms…

The interesting question of there being a subsidy for rooftop solar is the difference in subsidy to me between my roof having solar panels or my roof not having solar panels, not between my subsidy for my roof having solar panels or someone else's for their field having solar panels on it.

Re: EVs Are Essential Grid-Scale Storage

#199

Post by [deleted] »

sharemywin wrote: post #64
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…

State level regulations around installation driving up prices?

[deleted]

Re: EVs Are Essential Grid-Scale Storage

#200

Post by mnw21cam »

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/

Deep cycle lead-acid batteries are available around £100/kWh, and they'll last pretty-much as long as a LiFePo if managed sensibly.
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