What is geothermal energy?

Geothermal energy is natural heat energy extracted from the earth's crust.

Geothermal energy refers to the heat in rocks and geothermal fluids that can be scientifically and reasonably developed in the earth's crust. Thermal energy is the energy that determines the temperature of a substance. The geothermal energy of the earth's crust comes from the original structure of the planet and the radioactive decay of matter (it is uncertain at present, but it may be roughly equal in proportion).

The heat inside the earth is the heat energy produced by radioactive decay and the heat continuously lost during the formation of the earth. The mantle boundary temperature may reach above 4000 C (7200 F). The high temperature and high pressure inside the earth will cause some rocks to melt, while the solid mantle is plastic, which will cause some mantle to convection upward because it is lighter than the surrounding rocks. Rocks and water in the earth's crust are heated, sometimes as high as 370 degrees Celsius (700 degrees Fahrenheit).

The storage form of geothermal energy:

1, steam type

Characterized by the emission of steam. The pressure in the steam source region basically does not change with the depth. At the initial stage of steam discharge, it may be wet steam, dry saturated steam or superheated steam, but with the development of mining, the steam gradually dries or the superheat gradually increases. The steam temperature is higher than150 C, and the enthalpy is high.

2. Dry-hot rock types

Generally, it refers to thermal rock mass without water or steam, which is a greater resource than steam, hot water and geothermal resources. Shallow burial (within 10km) of dry and impermeable hot rock mass has mining value. The borehole is used to penetrate this rock mass, so that the rock mass between wells is broken, and then fluid is injected to form an artificial circulation channel, and the system heat energy is taken out through circulation.

Reference to the above content: Baidu Encyclopedia Geothermal Energy