[Power] "Next generation utility wins contract for UK's biggest battery"

[T i m]

We already have one and it's pretty big, it's called 'the sea'. ;-)

Cheers, T i m

[Theo]

The argument goes that, since PE=mgh, you can get away with less m by having a bigger h. If the mine is 2km down, you can use 10x less water than pumped storage where you might only get 200m.

Unfortunately, the problem is that mines contain corrosive things and all those nice support structures that are keeping the mine open may not stay up for long with all this corrosive water sloshing about.

THeo

[The Other Mike]

Something liquid at room temperature and quite dense would be preferable. Mercury would appear an optimum choice. As for finding an old mine with a shaft still usable and with roadways still inctact then you are f***ed before you even start.

[Chris Hogg]

The one they're talking about in Germany is still a working coal mine, but due for closure next year. As to whether an old long-closed mine can be reinstated would depend very much on the type of mine and the geology of the site. Coal mines would be near impossible I would think, but many tin and copper mines in Devon and Cornwall have been re-opened in the past and even relatively recently after decades of being closed.

[The Natural Philosopher]

It takes around 4-6 years to pump old mines dry before they can be reopened.

[Chris Hogg]

I hope the Germans have a rather shorter time in mind, otherwise they'd get 4 hours of 200MW, followed by a 4-6 year delay while they pumped it out again!

[bert]

Well some of our old coal mines are under the North Sea off the Durham coast.

[The Natural Philosopher]

lifetime of seawater pumps and turbines is not great.

And if they bitch about fracking clean water plus a teensy bit of antibacterial into the ground, what would they think about dumping tonnes of seawater into the aquifers.

Oh. Of course. Greens dont think. They emote with their 'emotional intelligence'

[Tim Streater]

Ah, so you're suggesting pumping seawater into old coal mines. Does that work for the ones that are miles from the sea? And can you guarantee no leakage of seawater into local aquifers?

I floated my questions above in the expectation that some numpty would be drawn to them like a moth to a burning fart, and sure enough ...

[Chris Hogg]

On the Canaries, they have a pumped storage scheme where sea water is pumped up to an extinct volcano crater and then run back down again to generate electricity.

Controversial as to whether it's cost-effective or doing what was predicted.

As for mines, there are several tin mines in west Cornwall that are on cliff tops, and whose galleries run out over a mile under the sea,

2000 ft deep. See and

Quotes from the second link "During the 20th century Geevor drove over

85 miles (137 km) of tunnels" and "On average over a million gallons of water, a quarter of which was sea-water, was pumped from the mine daily" So no real problems with pumping sea water. But I can't imagine anyone even remotely wanting to use it for a pumped storage scheme!

I was lucky enough to go to the bottom of Geevor shortly before it closed in 1990.

Before it closed in 1990 I was lucky enough to go to the bottom of Geevor.

[Tim Streater]

If it's been closed for 27 years I imagine it's full by now.

Are we still in the mine? Bit of an echo round here :-)

[Chris Hogg]

Yebbut still capable of being pumped out if the need arose. Mines in granite keep their structures pretty well and don't tend to collapse. But with any mine, if you want to use it as an energy store, you have to pump out not only the water you've run in, in the process of generating electricity, but also the 'coming water' which in Geevor's case was 1M gallons per day, and you have to do it sharpish before the next demand period. Big pumps both in terms of volume capacity and power!

LOL and clever! I thought I'd deleted that bit by accident but apparently it was just off the bottom of the screen. :-)

[bert]

And we reply to it tongue in cheek in the expectation... you know the rest.

[Vir Campestris]

Especially as by then it will be quite heavily polluted.

Andy