[Power] Germans convert decommissioned coal mine into pumped-storage generator

That's a bit rich. Germany has just done a massive move back to coal.

Bit premature that "Germans convert ...."

Interesting. To complain that it's only 200MW for 4 hours would be churlish; better than nothing, and there are plenty of coal mines in that area that could possibly be so modified*. It would all add up, although it doesn't say what the cost is going to be. I'm also not clear what the upper reservoir is going to be; some sort of bunded lagoon, perhaps. It may already exist. What would worry me slightly is that the pumps/turbines would be at the bottom of the mine and so under water for most of the time, and deep water at that, making servicing and repair more difficult. Perhaps they can isolate them in some way.

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So how does that work then? Is it just a simple lake on two levels and a turbine house? Brian

Essentially yes, with the mine providing the lower lake

Hate to think what all the coal dust will do to the turbines

I very much doubt the bottom of the mine is a single level. There will be multiple levels so use the lower ones as the lower "lake" and have the kit in the higher ones. Having turbines at bottom of a mine shaft isn't new:

TBH repeatedly flooding and pumping out a level (or levels) worries me more. The varying water pressures will facture the rock and hasten the collapse of the workings.

Well not where they where dug... They back fill if they have any spoil, no point in transporting that to the surface.

That makes sense coal by it's nature is often layered with shales, lime and sandstones. None of which are pariculary stable, though some sandstones are very fine and hard.

Hmm. Interesting. I can see a lot of problems that would have to be overcome.

En el artículo , Dave Liquorice escribió:

DO you think the upper reservoir would be above ground or in the higher levels of the mine?

As you want the biggest head of water you can get, above ground. As previously stated the changing water pressures will fracture the rock, not sure I'd like to be in a mine below a flooded level with dubious stabilty...