Geothermal is the natural heat of the Earth. The temperature at the Earth’s centre is estimated to be 5,500^oC – almost as hot as the surface of the Sun. This heat is derived from the original formation of the planet and from the decay of the radioactive elements in the Earth’s crust. It is transferred to the subsurface by conduction and convection.

For centuries, geothermal springs have been used for bathing, heating and cooking. But only in the early 20^th century did people start to consider the heat from inside the Earth as a practical source of energy with huge potential. Geothermal energy is now used to produce electricity, to heat and cool buildings as well as for other industrial purposes like grain and lumber drying, pulp and paper processing, fruit and vegetable cultivation, soil warming and many others.

The exploitable geothermal resources are found throughout the world and are utilized nowadays in 83 countries. Only a small fraction of geothermal has been used so far and there is enough room for development in both electricity generation and direct use applications. Geothermal represents a promising energy source to satisfy the growing energy needs.

Download the IGA ‘Geothermal Quick guide’ Brochure (pdf, 4 MB) to find out more about geothermal.

There is something good for each letter: