There are some very deep mines on the planet with constant high temperatures. Would it be possible to melt down a huge block of copper or aluminum to act as a heat-sink, connect it to well-insulated heat-pipes that transfer that heat to the surface, and use that heat differential with the ambient air temperature to power a huge, industrial Stirling engine for the purpose of electricity production?

I’ve never heard of anyone doing this, so I assume this idea has one or more fatal flaws (cost? low theoretical output? something else?).

Topics: science, energy, physics, engineering, green