How is thermal energy produced?

Thermal energy is produced by collecting heat from the sun or the earth's crust. Solar thermal energy is produced by using mirrors to focus solar radiation onto a liquid, which is boiled to create steam. That steam then spins an electric turbine. Geothermal energy is extruded from heated layers of rock deep in the earth's crust. Water is naturally superheated by the earth's molten core. Geothermal energy systems drill down to access that water and bring it to the surface to create steam and spin an electric turbine. Geothermal plants are made renewable by condensing and essentially recycling that water and sending it back down to be reheated.

Thermal energy is also used without an electric turbine. The heat inherent in thermal energy is used directly to heat homes, water and pools. Solar thermal energy is the primary source for hot water and warm swimming pools. Both solar and geothermal energy are used to heat homes. All produce thermal energy by cycling water, an antifreeze solution (in northern climates), or air through collectors on a roof (solar) or through pipes running through the earth below the frost line (geothermal).