Geothermal energy is a form of energy generated and stored in the Earth. 20% of the Geothermal energy of the Earth’s crust originates from heat generated when the planet was formed. The other 80% comes from the radioactive decay of minerals (80%).
The use of geothermal energy for bathing and central heating dates back to ancient Roman times, but the term is now better known for electricity generation. 24 countries produce about 11GW of geothermal electricity between them. An additional 28GW is installed for heating and industrial processes.
Geothermal energy is reliable, sustainable, cost effective and environmentally friendly. Recent technological advances have noticeably increased the range of possible resources, especially for applications such as home heating.
The Earth’s geothermal resources are theoretically more than adequate to supply humanity’s energy needs, but only a small percentage can be developed economically. Both exploration for deep resources and drilling for electrical production is very expensive. However these costs like many other renewable energy costs are falling as more is invested in research and greater industry experience is gained. In the last 20 years the cost of generating geothermal power has decreased by 25%.