Why is geothermal energy renewable source of energy?

Geothermal energy is renewable source of energy because Earth's heat is being constantly replenished.

The earth's heat mostly originates from the radioactive decay of elements such as uranium.

Geothermal energy is environmentally friendlier than fossil fuels because it is connected with far less greenhouse gas emissions. The average geothermal power plant emits in average 122 kg of CO2 per megawatt-hour of electricity, which is negligible amount compared to fossil fuels fired power plants.

Geothermal energy is very abundant source of energy with excellent potential.

Geothermal energy can improve our energy security and energy independence because by using more geothermal energy we would need to import less foreign oil and other expensive fuels.

U.S. leads the world in geothermal energy development.

California is nation's geothermal energy leader.

Geothermal energy is found along major plate boundaries where earthquakes and volcanoes are concentrated.

The first geothermal power plant was built in Landarello, Italy in 1904.

The largest geothermal power plant complex in the world is located at the Geysers, California.

Geothermal power plants are currently commercially viable only in areas on the edges of tectonic plates. The further technological improvement, especially regarding drilling, should help expand areas where geothermal power plants could be viable to build.

Geothermal power plants have high upfront costs, mostly because drilling is extremely expensive process.

Geothermal power plants need to be carefully built in order not to affect the stability of land because this could lead to earthquakes.

Geothermal power plants do not require large areas to be built, and have small water requirements when compared with many other energy sources.

Geothermal power plants, once constructed, have very low maintenance costs.

Geothermal power plants have a lifespan of 30+ years.

Geothermal energy is not only used to create electricity, it is far more used for heating purposes (geothermal heat pumps).

In 2010, the price of a geothermal heat pump system for average home was around $7,500 (drilling excluded).

Geothermal energy is more expensive energy source when compared to fossil fuels but is cheaper than solar energy.

Geothermal energy doesn't depend on weather like this is the case with wind and solar. Earth's heat is available 24-7, in all seasons of the year.

Geothermal power plants are very efficient with a load factor of almost 90%.

In 2010, United States had 77 geothermal power plants operating, producing more than 3000 MW.

Geothermal energy is still less attractive to investors than solar and wind that attract the lion's share of total renewable energy investment.

Geothermal energy currently satisfies only around 0,3% of worldwide electricity demand.

Geothermal power plants are currently operating in just 24 countries of the world.