Geothermal energy is primarily used in China, where 20% of the world's geothermal energy is utilized, and Portugal's Azores islands. In the Azores, geothermal energy is used to power 5 power plants and heat pans of food buried in the ground. Setting up a home or large power plant using geothermal energy has initial costs, but operating costs are lower than fossil fuels. Geothermal energy is a renewable and clean source that avoids pollution and depletion concerns of fossil fuels, though high initial drilling costs are a potential drawback for some. Geothermal plants work by pumping underground hot water or steam through turbines to generate electricity.