Geothermal power is divided into two types: hydrothermal and petrothermal.
Promising sources of superheated water are multiple volcanic zones of the planet, including Kamchatka, Kuril, Japanese and Philippine Islands, and vast areas of the Cordilleras and the Andes.
Rocks with temperature less than 100° C are also widespread in the territories with low geological activity. That's why the most perspective is the usage of geotherms as a heat source.
The main advantage of geothermal energy is its practical inexhaustibility and complete independence from environmental conditions, time of day and year.
There are several ways to use the heat of terrestrial depths. Depending upon the temperature it is possible to turn water or a mixture of water and vapor for heat and hot water supply, power generation, or simultaneously for all these purposes. High-temperature heat of near-volcano areas and dry rocks are preferably used to generate electricity and heat. The structure of a plant depends on the type of the used source of geothermal energy.