Geothermal wells are wells which tap into the natural geothermal energy found beneath the Earth's crust. There are a number of different types which can be utilized in various ways, ranging from wells which connect to sources of steam which can be used to power turbines to wells utilized in geothermal heat pumps, which maintain stable indoor temperatures with the use of a recirculating water system. Most of the world's geothermal wells are found in areas of increased geological activity.
While the surface of the Earth can get quite cold at times, the area beneath the Earth's crust has a relatively stable temperature, and it is usually very hot. Geothermal energy utilizes this heat to generate electricity and to provide heating for various structures. The energy can either be used directly, in the form of geothermal wells which connect to sources of water and steam heated by the Earth, or indirectly, in the case of systems which pump water through hot regions under the Earth's crust.
Like other types of wells, geothermal wells are created by drilling into the Earth's surface and then sinking in well rings to keep the hole from collapsing. Production wells are geothermal wells which connect to sources of geothermal energy, while injection wells are designed to force water underground for the purpose of maintaining a steady supply of water in the geothermal system.
Some wells connect to geothermal power plants, which use the heated water to power turbines, or to transfer heat to other substances which can be used to generate energy. Power plants can feed their energy into the electrical grid, or generate power for a factory, school, or other large institution. One of the advantages to geothermal power is that it is renewable, making geothermal power plants popular in areas where people are concerned about sustainable energy.
Other geothermal wells are designed for use in heating systems. These wells connect with integrated heated and cooling systems, circulating warm water through a building in the winter to warm it up, and pulling heat out of a building in the summer so that it will cool down. These systems often utilize what are known as closed loop wells, which involve scores of wells sunk into the Earth and lined with sealed tubes which push water into and back out of the Earth in a continuous, closed system which is used to maintain the desired indoor temperature.