Types of Geothermal Energy
Dry Steam Geothermal Energy
Dry stream geothermal power plants use steam that is generated underground by the Earth’s heat directly, which eliminates the need for boilers and boiler fuels. This is not very common since dry steam resources are rare.
Flash Steam Geothermal Energy
Flash stream power plants spray fluids over 350 degrees Fahrenheit into a cooler liquid, causing fluid to vaporize quickly or “flash.” The vapor drives a turbine, which drives a generator. Any liquid remaining in the tank can be flashed again in a second tank to extract more energy.
Binary Cycle Power
A binary cycle power plant works with geothermal liquids at a lower temperature than dry stream and flash stream plants. The temperature of the water is less than 350 degrees Fahrenheit. Water is pumped from a geothermal well through a heat exchanger and cooled water is returned to the underground reservoir. A second fluid with a low boiling point is then pumped at a high pressure through the heat exchanger and then vaporizes directing the turbine. It is then condensed by a cold air radiator or cool water and cycles back through the heat exchanger.