Question

What do geothermal and solar energy have in common?

Answer 1

Both are relatively “unlimited” in terms of availability.

Explanation:

Geothermal is restricted by location, similar to hydro-power, although drilling wells could make it more widely available. But with the thermal source essentially being the earth’s core, it will be “available” almost as long as solar irradiation.

In both cases, life on earth would most likely be gone long before the thermal energy of either source is depleted.