Geothermal Power Plants

Geothermal electricity is produced using either of three types of power plant - dry steam, flash steam and binary power systems. Steam plants use steam and/or very hot water (greater than 300°F/ 149°C). In the dry steam system, steam is expanded through turbines which drive generators that generate electricity. In the Flash steam syste, very hot, high pressure water is depressurized falshed to produce steam which is then expanded through a turbine to produce electricity.

Binary power systems use more common, lower temperature water resources than the steam systems (100°F-300°F, 38°C-149°C). The hot water is mixed with another fluid that has a lower boiling point. This mixer is passed through the heat exchanger where the more volatile liquid vaporizes; this drives the turbines and produces electricity. The remaining secondary fluid and the geothermal fluid are both recycled with the latter being returned to the reservoir, creating a closed cycle where nothing is emmitted.

For further information on Geothermal Energy systems and how they work click here.