Geothermal energy makes use of the natural heat energy in the deep layers of the Earth's crust. For example, underground water reservoirs are drilled, and hot steam is brought to the surface. This is used to generate electricity or to heat buildings.
In geothermal power plants, the hot water or steam from the boreholes is pumped to the surface and passed through turbines to generate electricity. After electricity is generated, the cooled water is returned to the subsurface, where it heats up again. This continuous supply of heat allows for sustainable, long-term electricity production without significant greenhouse gas emissions.
Geothermal energy is a renewable energy source because water is continually replenished by precipitation or meltwater. This makes it available in almost unlimited supply, unlike limited fossil fuels. In addition, geothermal energy causes very low greenhouse gas emissions compared to fossil fuels. As a result, it can help reduce emissions of CO2 and other harmful gases and combat climate change.