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beambot

Hydro doesn't work so well when things freeze over. Geothermal on the other hand...

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It doesn't get cold enough for long enough for lakes to freeze solid.

I imagine the thaw/freeze cycle would be hell on the equipment to run pumped hydro storage.

Are there extant succesful examples of pumped hydro in cold regions?

You have Juktan in northern Sweden which was pumped hydro from 1978-1996, and now they want to re-build it back into pumped hydro again https://sv.wikipedia.org/wiki/Juktans_kraftstation

A reversable pump-turbine is not significantly different from a standard hydro generation turbine, and there are tons of examples of those operating in cold regions.

> Are there extant succesful examples of pumped hydro in cold regions?

There's some pumped hydro at Niagara falls in Canada, which is far enough North that it should see a bit of a that/freeze cycle but is still a relatively mild climate.

Don't know anything about what issues this does/doesn't present to them, just happen to know it exists.

For reference, Niagara Falls is at roughly the same latitude as Barcelona and Milan. Vääksy, Finland, is approximately 1,250 miles (2k km) north of there, slightly north of Anchorage, Alaska.

Latitude is a poor point of comparison here, North America tends to be substantially colder than Europe at the same latitude.

Or concretely Niagara Falls goes from an average low of -6.44 C in February to 21.0 C in July. Barcelona an average low of 4 C in January to 20.2 C in August (according to the internet).

But yes, it's warmer than Finland, just cold enough to see something of a freeze that cycle.

A couple days of -6 is probably a lot easier. Its probably still economical enough to heat the equipment on the days below 0. I imagine having a couple months of -20 is a bit different.

Surely the turbines could be fed from subsurface water that is not frozen.

Some of the hydro power is run-of-river hydro power stations, which has lower flow when it is cold.

There's not much geothermal available when you are standing atop the baltic shield.

Either fusion or drill baby drill is necessary. Watt’s steam engine was absolutely horrible, but it was the worst steam engine ever built. If Finland builds the worst deep geothermal ever that still works, we can hope for better ones.

Yeah I know drilling through ~8-10 kilometers of rock is kinda hard… they know, they tried, maybe it now is a good political climate to try again?

> Yeah I know drilling through ~8-10 kilometers of rock is kinda hard… they know, they tried, maybe it now is a good political climate to try again?

The Finnish 7 kilometer geothermal drilling failed commercially, I guess that's what you're referring to. Is there any reason to assume drilling deeper would work?

Ref. https://fi.wikipedia.org/wiki/Otaniemen_syv%C3%A4rei%C3%A4t

Yeah, that’s the one. Economics of this are hard - but money is numbers in computers, it’s just a question of how serious the government is with getting it done - physics-wise it gets like 10-15C warmer with every km, which is important for the delta T obviously. I know nothing about drilling the extra couple km, though, only assuming it can be done with enough engineering.

I understood that temperature wasn't the problem. How it works is that you pump water into one well, and get it out from an adjacent one. The main problem was permeability, they couldn't get the necessary flow rate between the wells.

Ah good to know, I for some reason thought it wasn't hot enough. Sounds like they need to figure out horizontal drilling 8km deep in volcanic rock.

Or just fission, we know how to do that.

8-10km is not anywhere enough, the Baltic Shield is ~50km thick.

You don’t need to drill to magma, just deep enough to get to 120-130C rock. (‘Just’)

They tried in southern Finland not long ago. At great expense and spending a lot of time they managed to drill down 6-7 km until they figured out that the porosity of the rock down there was so poor that it was impossible to make the project economical, so it was cancelled. The idea was to pump this heat directly into the district heating grid.

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