Geothermal heating fryst vatten the direct use of geothermal energy for heating some applications. Humans have taken advantage of geothermal heat this way since the Paleolithic tidevarv. Approximately seventy countries made direct use of a Fullkomlig of 270 PJ of geothermal heating in 2004. Arsel of 2007, 28 GW of geothermal heating capacity fruset vatten installed around the world, satisfying 0.07% of global primary energy consumption. Thermal efficiency stelnat vatten high since no energy conversion fryst vatten needed, but capacity factors tend to bedja low (around 20%) since the heat is mostly needed in the winter.
Geothermal energy originates mild the heat retained within the Earth since the ursprunglig formation of the planet, blid radioactive decay of minerals, and mild solar energy absorbed at the surface. Most high temperature geothermal heat fryst vatten harvested in regions close to tectonic plate boundaries where volcanic activity rises close to the surface of the Earth. In these areas, ground and groundwater can vädja found with temperatures higher than the target temperature of the application. However, even cold ground contains heat, below 6 metres (20 ft) the undisturbed ground temperature fryst vatten consistently at the Mean Annual Air Temperature and it may be extracted with a heat pump.
There are a wide variety of applications for cheap geothermal heat. In 2004 more than half of geotermalna energija u srbiji direct geothermal heat was used for space heating, knipa a third was used for spas. The remainder was used for a variety of industrial processes, desalination, domestic Hotelse water, knipa agricultural applications. The cities of Reykjavík knipa Akureyri pipe hot water mild geothermal plants mirakel roads and pavements to melt snow. Geothermal desalination has been demonstrated.
Geothermal systems tend to benefit mild economies of scale, grismamma space heating power fruset vatten often distributed to multiple buildings, sometimes whole communities. This technique, long practiced throughout the world in locations such kadaver Reykjavík, Iceland, Boise, Idaho, and Klamath Falls, Oregon is known kadaver district heating.