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EVs Are Essential Grid-Scale Storage

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Re: EVs Are Essential Grid-Scale Storage

#241

Post by danuker »

mnw21cam wrote: post #238
moffkalast wrote: post #223

Earlier quoted context omitted.

> they'll last pretty-much as long as a LiFePo if managed sensibly [Citation needed] Typically lead acid lifespan is around 10x less than lifepo4, even if kept within spec. But in practice it's hard to keep them in spec too, shit sulphates immediately when you look at it wrong.

https://www.youtube.com/watch?v=LPPUqLZOqCQ LiFePo is maybe 10x the lifespan of a normal Lead-Acid battery, if you're cycling it several times a day. A car battery for instance will not do very well in this test. But I'm talking about deep cycle Lead-Acid batteries, cycled every day or couple of days down to 70% capacity (so using 30%). This is a fairly typical workload if you're (for instance) using it as a backup f…

> so using 30%

In that case, they cost about $413/effective kWh.

Re: EVs Are Essential Grid-Scale Storage

#242

Post by moffkalast »

mnw21cam wrote: post #238
moffkalast wrote: post #223

Earlier quoted context omitted.

> they'll last pretty-much as long as a LiFePo if managed sensibly [Citation needed] Typically lead acid lifespan is around 10x less than lifepo4, even if kept within spec. But in practice it's hard to keep them in spec too, shit sulphates immediately when you look at it wrong.

https://www.youtube.com/watch?v=LPPUqLZOqCQ LiFePo is maybe 10x the lifespan of a normal Lead-Acid battery, if you're cycling it several times a day. A car battery for instance will not do very well in this test. But I'm talking about deep cycle Lead-Acid batteries, cycled every day or couple of days down to 70% capacity (so using 30%). This is a fairly typical workload if you're (for instance) using it as a backup f…

Well that was interesting, I wasn't aware that flooded lead acid was that much better and that AGM just plain sucks in general, which was also my observation dealing with UPS batteries.

Still, I would've expected that ever increasing self discharge would've made them far worse in comparison since it gets worse as the batteries age and you can end up losing major amounts of charge to it. Not sure if that's not as much of a problem for flooded as it is for AGM but I haven't heard it mentioned in the rundown.

Re: EVs Are Essential Grid-Scale Storage

#243

Post by fomine3 »

shagie wrote: post #137
ben-schaaf wrote: post #134

Earlier quoted context omitted.

> All model year 2013 and newer Nissan Leafs are approved for use with the FE-15 bidirectional charger, and the automaker states that battery warranties will not be affected. https://www.theverge.com/2022/9/12/23349971/nissan-leaf-bidi...

https://cleantechnica.com/2022/09/09/a-nissan-leaf-can-power... > Ideal for companies with fleet vehicles, the Fermata Energy Demand Charge Management application, along with the FE-15 charger, continuously monitors a building’s electrical loads, and may draw on the Nissan LEAF’s energy to provide power to the building during more expensive high-demand periods. In states with utility demand response programs, bi-dire…

V2H system with grid power outage support is available in Japan for a decade. I don't know what's the blocker in the US.

Re: EVs Are Essential Grid-Scale Storage

#244

Post by fomine3 »

londons_explore wrote: post #163
antipotoad wrote: post #146

Earlier quoted context omitted.

The idea of super-capacitors in cars is positively horrifying, knowing how explosive just the small ones can be. At grid level though, is there anything that speaks against them? Edit: to answer my own question, they look pretty good [1]. Significantly lower storage density than batteries (roughly 50Wh/L versus 420Wh/L for Li-ion), but still dense enough for this to be workable at grid level. The linked presentation…

Todays grids don't have much need for energy storage on the sub-10 second timeframe. Ie. there is rarely any money to be made by taking power from the grid now and returning it in 10 seconds. For technical reasons, thats because the 'spinning reserve' - which is momentum of every synchronous motor and generator across the nation - already adequately handles this. Also, large generation stations are required to have a…

Isn't it expected that 'spinning reserve' will be decreasing because we shutting down dirty power plants? Possibly it is needed in the future.

Re: EVs Are Essential Grid-Scale Storage

#245

Post by antisthenes »

londons_explore wrote: post #86
dmurray wrote: post #74

Earlier quoted context omitted.

> 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. If you can really treat the whole cost of the battery as X cents per charge cycle, disregarding the lifetime of the car/battery, this won't work at grid scale. Someone else will build a storage facility that just charges and discharges batteries, and they will outcompete rational EV owner…

Rooftop solar outcompetes solar farms because energy from a solar farm pays taxes and distribution costs before it is delivered to a user. Whereas rooftop solar energy is untaxed when it powers your laptop. > It only makes sense if the EV owner can somehow get charge capacity "for free" The EV owner has the power electronics 'for free' - ie. they have almost infinite lifespan, and just a capital cost. Additionally, t…

> Rooftop solar outcompetes solar farms because energy from a solar farm pays taxes and distribution costs before it is delivered to a user. Whereas rooftop solar energy is untaxed when it powers your laptop.

If you completely neglect the installation part, sure. Utility-scale solar farms have massive efficiencies of scale on purchasing panels and on labor-related overhead.

It's not that clear cut, basically.

I think what the EV model allows is for private car owners to essentially sell a part of their car back in increments, if for some reason their driving behavior changes and they don't need to drive as much as they used to.

Re: EVs Are Essential Grid-Scale Storage

#246

Post by enslavedrobot »

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…

The number of cycles a battery can sustain strongly depends on its state of charge and depth of discharge. A cars battery can cycle between 30 and 70% charge for 20000 cycles or 0.8 cents/kWh according to your calculation.

Re: EVs Are Essential Grid-Scale Storage

#247

Post by adrianN »

fcantournet wrote: post #209
adrianN wrote: post #34

Earlier quoted context omitted.

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.

It is cheaper to run a nuclear power plant though. Like a lot. Also uses about 50x less material per MWh

It's not cheaper if you only want to run the nuclear power plant occasionally.

Re: EVs Are Essential Grid-Scale Storage

#248

Post by danans »

ajross wrote: post #229
danans wrote: post #217

Earlier quoted context omitted.

> That may change with the recent rollback of net metering in CA, which is making a battery system a requirement to reach break even on cost. NEM3.0 doesn't make a battery a requirement to break even on costs, it just extends the payback time of solar without batteries by 3-5 years. It reduces the still absurdly long payback time of home battery storage somewhat, though. Only when you can sell power back to the grid…

I've seen a lot of different numbers thrown around (and to be clear: I'm in Oregon and not part of the fight). Let it suffice that NEM3.0 makes the relative benefits of a battery for time shifting (and thus the costs of a solar system without a battery, as was typical for early installations) much, much higher.

I guess it depends on the rate structure you have. Higher rate variance between off and on peak periods definitely helps with the economic case for batteries, since it offers an arbitrage opportunity.

I haven't done the math yet to figure out how that variance relates to payback time for batteries, but would be a fun exercise.

Re: EVs Are Essential Grid-Scale Storage

#249

Post by jacquesm »

kkfx wrote: post #220
jacquesm wrote: post #192

Earlier quoted context omitted.

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 s…

Fronius have hybrid inverter for 400V lithium batteries, witch are essentially the same used in cars, the missing part is the integration p.v. inverter-car's BMS. Personally having an EV and a Victron inverter with batteries and same vendor car charger I HATE the fact I can't even adapt charging amps depending on p.v. available power in AC charging.

Yes, this lack of standardization and ability to communicate is infuriating. I don't have an EV but even without that adding a battery to an existing setup is not that simple, besides being in theory a massive fire hazard, so it can't be in the house.

With HA and a bunch of scripts you can actually get quite far in automating all this, but when the grid fails everything will shut down.

I'd love to see these babies become more easily (and cheaper!) to source:

https://en.wikipedia.org/wiki/Lithium-titanate_battery

The energy density isn't super but for stationary applications that's fine. 6K+ cycles, fast charging, what's not to like?

Re: EVs Are Essential Grid-Scale Storage

#250

Post by sgt »

mnw21cam wrote: post #237
sgt wrote: post #221

Earlier quoted context omitted.

Managing lead-acid sensibly in my experience means never letting levels go below 40%. Temperature too I suppose. I didn't know they could last as long as LiFePo though. Is this really true? If this is true, why don't we just use more lead-acid batteries then?

LiFePo can last longer than Lead-Acid. It depends on the usage. LiFePo has a very high maximum cycle count. But after ten years, they'll die anyway. The only way that you can actually achieve a cycle count as high as the specification says is if you're cycling the battery two or three times a day, which I can believe if you're doing grid-levelling, but not if you're providing backup for your solar panels. For lead-ac…

This is very insightful, thank you. I guess for price per kWh, lead-acid is also still unbeatable. And as you mention, deep cycle can give good lifetime as long as you don't go below 40%. I see deep cycle batteries come in all kinds of voltages though - is there a preference? I've seen huge 1000Ah batteries with 4V or 6V.
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