In order to generate electricity from geothermal sources, you need a reservoir of water greater than 100°C within a reasonable distance from the surface, usually about 1500 m.
The principle is very simple - drill a hole into the reservoir to tap into the hot water, pump the water to the surface under pressure so it doesn't boil, and then "flash" (release the pressure) the water in a turbine so that the steam spins the turbine to turn a generator and produce electricity. Then you capture the steam, condense it, and pump the water back into the reservoir in an injection well, to keep the cycle going.
The "practicality" of geothermal energy depends on several factors:
1. No energy source is practical in a very remote area, so you need to consider the distance to the electrical load, or at least a major transmission line.
2. Geothermal water almost invariably contains a lot of dissolved solids, especially carbonates and sulfates, which tend to precipitate on the pipes and turbines, and that is expensive to clean.
3. Geothermal energy will only work where the Earth's crust is thin enough to have a high geothermal gradient, such as in the Beowawe area of Nevada.
4. The cost per MWH of installed capacity is very high. Not as high as nuclear, but much higher than coal.
However the "fuel" for geothermal energy is free and long lived. It doesn't produce any greenhouse gases.
The principle is very simple - drill a hole into the reservoir to tap into the hot water, pump the water to the surface under pressure so it doesn't boil, and then "flash" (release the pressure) the water in a turbine so that the steam spins the turbine to turn a generator and produce electricity. Then you capture the steam, condense it, and pump the water back into the reservoir in an injection well, to keep the cycle going.
The "practicality" of geothermal energy depends on several factors:
1. No energy source is practical in a very remote area, so you need to consider the distance to the electrical load, or at least a major transmission line.
2. Geothermal water almost invariably contains a lot of dissolved solids, especially carbonates and sulfates, which tend to precipitate on the pipes and turbines, and that is expensive to clean.
3. Geothermal energy will only work where the Earth's crust is thin enough to have a high geothermal gradient, such as in the Beowawe area of Nevada.
4. The cost per MWH of installed capacity is very high. Not as high as nuclear, but much higher than coal.
However the "fuel" for geothermal energy is free and long lived. It doesn't produce any greenhouse gases.