Geothermal energy is the heat that comes from our earth. It is cheap to produce and buy. It came from hot springs back in the 1800s. Geothermal power plants require high temperature between 300 and 700 degrees.Geothermal orinates form 20% from the planet radioactive decay of minerals 80%. If you brake down the word geothermal, geo means earth, and thermal means heat.