Have you heard of Tesla's batter in south Australia? It was recently expanded to 193 MWh. Care to guess how long it'll run at full power? Around 60-100 minutes. At its rated power of 100 MW, it can power around 25% of South Australia's lowest demand. That's it. At peak demand, the fraction is lower still.

Cars have a fraction of the energy storage capacity of a single battery site and not all cars are connected to the grid at all times and neither will all their stored energy be usable.

Batteries aren't the silver bullet many imaging them to be. The real solution is expanding transmission capacity, building more renewables and supplementing that by nuclear or hydro.

I don't know if there's enough lithium in the world to stabilize a global renewable grid and make 100 million electric cars per year forever and make 1.5 billion phones a year and all the other things we use batteries for.

Lithium is very abundant. It's the 25th most abundant element at about 20 mg per kg in the Earth's crust. It is present in seawater at a concentration of about 0.2 ppm in seawater, about 230 billion tons total.

If electricity is going to be so cheap then we can just extract lithium from seawater.

Plus dead lithium batteries can of course be used as a high grade ore.

See https://en.wikipedia.org/wiki/Lithium

Hopefully we start to recycle batteries better. Most people throw their old broken phone in a landfill from what I gather. (broken, there is a market for non-broken phones)

25% of lowest demand sounds amazing! I'm mostly a pessimist about renewables due to the storage issue so I would have guessed more like 2-5%.

Assuming lowest demand is at night, that means that building just 3 more batteries you could power the whole state for an hour at night?

Agree, I'm missing some context to see why your parent post thought this was good enough. I suspect that "Lowest Demand" is being thought of in two different ways.

even at the lowest demand, a large, grid-connected battery can only provide minutes of back up power, and that too for only a fraction of already low demand.

A storage battery is not a viable means of balancing demand and supply over a time period longer than minutes.

What's needed is not more batteries but better transmission, more hydro where possible and where hydro is not possible, more nuclear.

When you're talking about lowest demand are you talking about for the whole grid? A city block? A building? A condo?

And I agree. I worked in solar and storage for a while. It's not a replacement, it's just an extension.

It works out ok for a battery system for a building but anything larger they just don't last long enough

Only the south australian grid, which is not a relatively large grid.

South Australia's population is small, under two million and it's demand fluctuates between 400 - 3000 MW. For comparison, the Canadian province of New Brunswick has a comparable peak demand but fewer than a million people.

For the comparison, average nuclear power plant produces 1000MW around the clock.

The goal of Australia batteries was to normalize short production/consumption fluctuations, not as general universal battery storage to deal with renewable uneven production.

My point was simply to illustrate that batteries are not a viable energy storage method for the scale of energy required on even a small power grid. South Australia's power grid is relatively small compared to many similar regions.

As an electric car owner, do I want to give my limited lithium battery charge cycle lifespan back to the network? This storage isn't "free" to the vehicle owner - charging and feeding back will contribute to the total charge cycles on your very expensive battery pack, which of course reduces range over time. I'd need to be heavily convinced by the economic arguments outweighing the wear on a very expensive vehicle component before I'd consider this.

When you come to resell an electric car, the condition of the battery is going to be significant in resale value too.

There would presumably be a zip code lottery element here too - would some areas of a given country make much greater demands of resident's privately owned car batteries than others?

> This storage isn't "free" to the vehicle owner

Just set the price at which you are willing to sell so that you make a profit overall.

I've seen this suggested often but I don't think I've ever seen any information about how it'd actually work in practise. Do the car companies actually want to do it, how is the car owner compensated for the battery wear and tear and who'd be in control of the management (government regulators, energy companies, car manufacturers).

Are there any examples of pilot schemes that have used cars in this way?

It isn't the silver bullet some people say it is. Firstly, as others mentioned it really hammers the battery life. Secondly, it requires cars not being full so they can be topped up, which means less range.

Not to mention I don't think the local grid to houses can support loads of cars suddenly getting charged at once, which is what you want for big wind spikes.

You could at least program the cars to adjust their charging based upon cost - e.g. if you leave it overnight and between 2-5am electricity prices go negative it could try to charge most of the battery during this period.

Additionally you could program cars to feed into the grid when the price goes high enough to justify the cost of cycling the battery. This would help deal with unexpected events.

Yeah it's very much a niche but it's possible to buy chargers that integrate with Octopus Agile and do exactly that in the UK. Alternatively some of us are doing it with automations in apps like Home Assistant.

Nissan and Hyundai already produce cars with vehicle to grid (Nissan) and vehicle to load (Hyundai).

IMO recycling batteries after use in cars is a more interesting idea. A 20% reduction in a cars range is significant but not an issue in actual power storage.

That's not ideal, as it would eat through the battery's cycle life at a much quicker rate.