As I said before, geothermal heat pumps use the earth's continual temperatures for heating and cooling.
According to the U.S. Environmental Protection Agency (EPA), geothermal heat pumps are the most energy efficient, environmentally clean, and cost effective systems used for temperature control.
Cost (Economic Impact)
Geothermal power is becoming cheaper as technology improves. According to the Union of Concerned Scientists, the cost of operating geothermal power plants has lowered by as much as 50% since 1980.
Geothermal energy doesn't cause pollution, as no fuels are burned. Closed-loop systems don't send emissions in to the air, but open-loop systems exclude hydrogen sulfide, carbon dioxide, ammonia, methane, and boron.