OT Geothermal energy

Been talked about for several decades. The Rosemanowes 'hot rocks' project in Cornwall in the 1970's was one such.

There are a few other sites across the world, but mostly you need hot rock not too far below the surface, otherwise it becomes too expensive to exploit. Iceland is often given as an example, and great claims made for it and how the UK will benefit from an interconnector up to Iceland, which seems to have gone quite. But Iceland's total geothermal capacity is only 750MW, so they don't make much use of it themselves.

Small scale use here...

They make a lot of use of it for heating and presumably don't use it more for electricity generation because they have even cheaper hydro power, pretty much everyone's favourite renewable.

I don't think it is an indication of how much power they could generate economically from geothermal.

CEGB were doing research on this in the 1970s from the Marchwood Engineering Labs, on the Solent. Conveniently, this region is another reasonable hot spot.

IIRC there turned out to be two issues, I think the main ones was that the output would drop off significantly after ~ 50 years because you would have cooled off such a lot of rock by then, and the other was you lose something like half of the water that you pump down.

I think that Marchwood were also looking at wave power (who remembers Salter's ducks?) and windmills. Prior to that they had quite a substantial rig looking into Magnetohydrodynamics.

Which often uses fracking type technology. I'm sure there will be even more complaints about tremors.

A corner of the pool will be partially heated by a geothermal borehole. It used to be the kiddies corner when I swam there in about

But when drilling the borehole, they had to stop because they hit a patch of high water flow. I don't know exactly what that means, but I assume that it was a geological fault or some-such, so that water they pumped down to be heated just leaked away instead of coming back up to the surface, but that may not be the explanation. Whatever, they're having to supplement the geothermal heating by conventional heat pumps.

It always struck me as a ridiculously expensive scheme. Virtue signalling writ large!

I think this is because its bloody dangerous. There is a lot of energy, but its very destructive energy. Have you ever tipped a bucket of water down a bore hole on Lanzerote? Best run quick if you try it.

Brian

There is this that works: