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Geothermal's Time Has Come

22 points| pingou | 3 months ago |economist.com

27 comments

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phreeza|3 months ago

Pasting a comment here I made on the previous article:

To me the most important fact to keep in mind about geothermal is that the energy flow across the crust is ~0.1W/m^2. Compare that to the sun which has >100W/m^2 even at high latitudes. Of course this does not mean geothermal is useless (in particular heat pumps, if you count those, are great), but it goes a long way to explaining why geothermal isn't seeing the same explosion as solar.

griffzhowl|3 months ago

> the energy flow across the crust is ~0.1W/m^2

It's a misleading comparison. This is only the average amount of heat that diffuses through an ordinary patch of surface, and has more or less nothing to do with how a geothermal plant works, since they don't harvest heat by covering a large area of surface with conducting material.

The surface heat flow is low because rock acts as an insulator. If you drill down to where it's hot and draw the heat up you obviously get orders of magnitude larger flows of energy to the surface.

echelon|3 months ago

> Compare that to the sun which has >100W/m^2 even at high latitudes.

Some places are covered with snow and get under 8 hours of sun a day, but your point still stands.

You know it's pretty compelling when there are several concurrent multi-billion dollar projects to transmit solar power from Africa, by undersea cable, to mainland Europe.

linhns|3 months ago

Should the technologies mentioned in the article can be perfected for large scale use, we would see a boom in geothermal, even larger than that of solar, as intermittency is automatically resolved.

Iceland and Australia would become new powers imho.

SomeHacker44|3 months ago

I was recently quoted over $1.2M for a geothermal heat pump for around 800,000 BTUs in upstate NE NY. The property is not even worth that. This used three wells drilled about 600 feet.

On the other hand the estimate for a propane heater upgrade from the oil boiler was only $20,000 (I imagine it was an underestimate though). And window units for the 20-odd rooms would be less than $500 each. Or a lot of split systems for $2-4k a room.

websiteapi|3 months ago

seems simpler to use solar to heat up rock and insulate it for use during the winter than to drill, but i'm not an engineer.

this is already what the earth is doing, but at least now we can direct that energy where we want.

Groxx|3 months ago

thermal sand batteries might be interesting to you, if you haven't seen them before