Geothermal heat comes from our planet’s molten core which, at over 10,000 degrees Fahrenheit, is as hot as the surface of the sun. As the heat radiates, it gradually cools.
Here they have drilled wells between 2,000 feet and two miles deep, where the temperature is only around 600 degrees Fahrenheit. Very salty and very hot water, called brine, as well as steam, rises sharply. The steam spins turbines, producing electricity, and the brine is pumped back into the ground, where it is warmed by the earth, replenishing the reservoir.
Is this type of well-managed more or less infinitely sustainable?