OT: Batteries for the grid - cost

I can't see a flaw there.

In practice I don't believe there would be an outage of such a magnitude. But you're right in demonstrating the futility of batteries.

The closest we might get to it is the sharing of car battery charges with the power network at peak times for some beneficial charge/discharge rate.

The area occupied by the Oz battery at Hornsdale is actually not very large, about 50 x 150 metres, 7,500 sq.m. or 0.0075 sq.km. See this Google map

The UK area is 240,000 sq.km which allows you 12 sq.km for each of the

I'd be interested to know how much land it would sterilise if it accidentally got shorted.

As much energy as a 4 megaton H bomb.

I did a similar calculation a while back and got 42,000 batteries needed, but I didn't then know the MWh capacity of Tesla's Oz battery, and assumed it to be 100MWh, half what you've used (yours is the correct figure), so taking that into account, our calculations agree but by different routes.

Its always a problem, that of energy storage, but most of the schemes I see do not support anything but a small area for a short time, and tend to use ex electric car batteries, lots of them. Second hand of course but cheap and still usable for a good number of cycles. Brian

For a renewables-only power generation system, such an outage would be a regular feature. We had one this year, in the latter part of January, when wind/solar were between them generating 1% at best of our requirements, for several days.

They're designed for different things. Hornsdale is intended for grid stabilisation and time shifting, ie very rapid response over a short time (minutes/hours). A battery designed for a 'power outage' of a week only needs enough power output to cover the peak.

Hornsdale has a 194MWh capacity with a 150MW peak output. Your hypothetical

Enormous numbers, but not as enormous as the 3TW you'd get from scaling up Hornsdale.

In reality, for this scale you'd probably be looking at flow batteries. It would be interesting to do the calculation of how much electrolyte you'd need and where you would put it.

Theo

You've been watching too much Chernobyl.

You can't do sums

Now that is interesting. I only chose Hornsdale because it's the only largish battery I'm aware of, and I needed some numbers to start from. Are there any others, any that might match the requirement bettr?

What DO you mean?

Are there any such batteries in operation, do you know? Not on the scale needed for the UK, I'm sure, but possibly for isolated island communities that have no access to traditional generators such as coal, nukes or even hydro, but can only use diesel, wind and solar.

If you are paying a pound for 4 Wh I wish I was your supplier

I am far more scared of grid scale batteries and hydro schemes than any nuclear power station.

It's not cost per Wh. It's capital cost. Which will be amortised over lifetime recharge cycles, and combined with efficiency and operational costs to give Wh cost. Maybe 1000 charge cycles, 90% efficiency, + operational cost = ~50p per KWh. Looks ball park.

It's not cost per Wh. It's capital cost. Which will be amortised over lifetime recharge cycles, and combined with efficiency and operational costs to give Wh cost. Maybe 1000 charge cycles, 90% efficiency, + operational cost = ~50p per KWh. Looks ball park.

Yebbut, how would a short release all the energy at once, like a bomb. You would get a small local fire/blast and the rest of the system would shut down.

I see you can't read. A 70Ah 12v lead acid is around £70 for 840Wh. That is *lead acid* at a pound for 12Wh, for a dangerous battery than can explode if shorted.

An 11v 20AH lithium pack is nearly as expensive at £50. And that works out at about 4Wh per £

I'd say his figures are not far off.

he wasn't talking about supplies of 'electricity' but 'battery capacity'.

That doesn't sound right (by many orders of magnitude).

TNT energy equivalent is about 4 x 10^9 per T

So it would be about 180T TNT energy equivalent but delivered on a diffusion limited timescale rather than as a supersonic detonation. A big bang but I'd be very surprised if there was a supersonic shockwave.

It would be a spectacular pale purple lithium fire though. The e-cigs go off exceptionally well as impromptu fireworks when overcharged. Sooner or later one *will* go pop and test their fire suppression system out.

Only the low yield W54 tactical nuclear warhead had such a low power.