The heat stored in the Earth’s crust, known as geothermal energy, is carbon-free and effectively inexhaustible. There’s enough of it to run all of civilization for generations, if it could be cost-effectively tapped.
Tapping it turns out to be no small feat, but efforts have ramped up recently due to new urgency by the climate crisis and the search for low-carbon alternatives to fossil fuels.
The cutting edge technological developments in the field (including, yes, lasers) are devoted to drilling deeper and deeper, into hotter and hotter rock. Heat anywhere from 302°F (150°C) up to 703°F (373°C), where water enters its “supercritical” phase and above, can be used to profitably generate electricity.
For new builds, though, “geothermal is a no brainer,” says Adam Santry, the president of Allied Well Drilling. “You don’t need any [tax] credits. Rolling [a GSHP] into your mortgage, you are cash flow positive that first month.” The savings on heat are greater than the loan payment on the GSHP, right off the jump.