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EVs Are Essential Grid-Scale Storage

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Re: EVs Are Essential Grid-Scale Storage

#141

Post by AtlasBarfed »

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…

Either Chinese companies are reaping huge profits on batteries, or the American companies that repackage them into their bespoke platforms (EGo batteries don't work with greenworks or ryobi AFAIK because they put different plastic shapes around the battery cells so you're locked into their ecosystem for example) are reaping the profits.

Hopefully, 200-230 wh/kg LFP and 150 wh/kg sodium ion batteries should be a revelation in all use cases of batteries in the next year or so.

Tesla gets to operate at the extremes of volume, so they get to demand the best prices I would imagine, but the markup still seems astronomical in other things (like tools, home powerwalls, etc).

IMO there needs to be some governmental nudge. Battery prices (in theory) should be dropping in price such that many ICE-based tools will be fundamentally cheaper as batteries. An electric lawnmower shouldn't be more expensive than a very very dirty two stroke ICE lawnmower with the LFP/Sodium Ion that is coming to market.

But a lot of electric tool makers are using the reduced sound and superior torque abilities of electric tools as a price premium product. Things like lawnmowers and leaf blowers and snow blowers being high performance electric tools is like a "starter EV" for millions of Americans: it teaches them about recharging batteries, how EVs are better than ICEs in many ways (quieter, better torque, less smelly, no gasoline to spoil over winter) and how to deal with the annoyances (recharging).

Re: EVs Are Essential Grid-Scale Storage

#142

Post by btbuildem »

Decentralized energy storage does seem like one solution to the mismatch between renewable energy inflow, and energy usage. EV batteries certainly have the capacity (har har) to support a household during the low-generation times or to "cut the tops" off peak demand.

This approach though presupposes that everyone lives in suburban dwellings with garages/driveways, which is at odds with the more sustainable, higher density living scenarios (eg, urban centers) where public transit / alternate transportation usage is higher, and there is less space for personal cars. Eg someone on the 5th floor of a walkup is not going to run a cable from their window to their car parked at the other end of the block.

I think solutions like the Powerwall (or other brands' equivalents) might be a better way to go.

Re: EVs Are Essential Grid-Scale Storage

#144

Post by schiffern »

staringback wrote: post #140
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…

Let's hope you don't need to go anywhere urgently in the middle of the night... oops not enough battery to make it!

This is why you have an "always charge immediately to X%" option in the UI. You set this to whatever range an unexpected trip might require.

https://news.ycombinator.com/item?id=34518188

If your life is so chaotic that this doesn't work for some reason, don't turn on V1G

Re: EVs Are Essential Grid-Scale Storage

#145

Post by sokoloff »

bryanlarsen wrote: post #129
svggrfgovgf wrote: post #56

Earlier quoted context omitted.

People value things differently. You'd have to pay me way more than the 8 cents/kwh it cost me to use my battery. I'd want to be heavily compensated for the inconvenience of replacing the battery or car prematurely.

If I had a LiFePo4 battery that's good for 750,000 km I'd be willing to accept less than 8c because there's no way the rest of the car is going to last 750,000 km.

You'd be willing to take around a penny per km of battery lifespan? I accept your decision at face-value, but it hardly seems worth it to me.

That might just inevitably conclude in "OK, I guess others are willing to ask a lower price than I am, so I won't be in a position to participate in a V2G scheme."

Re: EVs Are Essential Grid-Scale Storage

#146

Post by antipotoad »

devmor wrote: post #85
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.

Batteries are extremely inefficient. Capacitors are much more resilient in terms of charge cycles (by orders of magnitude). If one were to build a "facility" to hold short term load, that's likely what they'd use. They just can't be used in cars because they're incredibly volatile and don't hold a charge for a long period of time.

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 proposes converting decommissioned power plants into grid-level capacitor storage facilities, since the transmission switchyards are often intact. Furthermore, all the technology is available today, and when built, capacitors require almost zero maintenance.

[1]: https://www.energy.gov/sites/prod/files/piprod/documents/Ses...

Re: EVs Are Essential Grid-Scale Storage

#147

Post by beckingz »

raxxorraxor wrote: post #87
vbezhenar wrote: post #73

Earlier quoted context omitted.

Phone battery is something like 4V. Watts depend on voltage. I guess home batteries use other voltage so their watt actually provides more electricity.

No, Watts should be independent of voltage, it is the product of voltage and ampere (don't know the exact English terms here). You perhaps mean ampere hours, I think that is often used for phones. But it is only ever meaningful if you have the respective fixed voltage and it often make sense for a batteries to quickly calculate how long they should last if you know how much ampere a device draws. It could also become…

Voltage isn't fixed across a discharge cycle.

As a chemical battery discharges, the voltage drops, so at the same load in amps you get less watts later.

Re: EVs Are Essential Grid-Scale Storage

#148

Post by AtlasBarfed »

sgerenser wrote: post #3
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…

House batteries are a much smaller market than batteries for EVs (at least right now). They also have other supporting components, safety features, etc. that add to the price. Since they’re normally installed as part of a solar install, they also usually qualify for a tax credit (between federal and state this can be over 50%) which further drives up the price because the vendor is able to capture a large chunk of th…

That's a failure of government with home solar.

Home solar + storage adds community-level resiliency in disasters and will reduce the grid load needed for home EV charging and industrial level charging used by electric tractor trailers. It should be a major complimentary effort of governmental policy along with grid scale solar/wind, grid scale storage, and whatever load leveling we can effectively decarbonize.

Good luck getting that through our deadlocked government.

Especially since

Re: EVs Are Essential Grid-Scale Storage

#149

Post by rbanffy »

manholio wrote: post #29
rbanffy wrote: post #24

Earlier quoted context omitted.

> 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 E…

It'll always be some marginal utility - the main purpose of the EV will always to be a car. You can use it to store energy purchased at non-peak hours so you can avoid using the grid at those times, something that'll probably raise peak prices, because if you need the energy right then, you really need it.

So, EV owners may use their cars to help reducing their energy costs and supplementing their PVs and fixed batteries (if any), but shouldn't expect a car to pay for itself like that.

Re: EVs Are Essential Grid-Scale Storage

#150

Post by fsh »

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…

The explanation is quite simple. Electricity from the grid is still very cheap. It therefore makes no economical sense to buy huge batteries for buffering your home solar panels. Since there is no demand, there are no products.
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