What surprises me is that so few people talk about geothermal power. That doesn’t pollute, and unlike solar and wind power, it’s available constantly. Here in Kentucky we don’t have volcanoes, but I have been told there’s enough geothermal energy under the state to heat our water, at least.
Probably not true. The warmth to heat water to 120 degrees is about a mile down (80 degrees per mile). Are you going to dig a well that deep? And pump water down and back? No.
Inevitably when people say "geothermal" they mean a network of wells, usually a few hundred feet deep that they pump water down and back. With enough wells the water stays lukewarm all year. Without enough wells, the ground will cool and they will lose efficiency. Then they pump the lukewarm water into an ordinary electric heat exchanger. They get the exact same efficiency as an air-warmed heat exchanger on a 50 degree day. On a zero degree day the geothermal would have the same 300% or more efficiency as the cool weather day. So the magic of geothermal is that it improves the heat exchange efficiency on very cold days. Otherwise it's like any other heat exchanger sitting on a concrete pad nest to a house.
Even around here, in the cold cold north, I have neighbors who use a buried heat exchange grid (it's at least 8 feet down where it's temp-stable all year) for both heating and cooling, and have done so for over 30 years. The big problem with such systems is, they're much more expensive up front -- but the difference between using electricity to merely move heat one way or the other versus buying fuel of some sort (winters only) is substantial.