FAQs
How does geothermal heat produce electricity?
Once geothermal waters reach the surface, the steam is sent to the power plant and used to drive generators to produce electricity, and the brine and gases are re-injected back into the injection zone below the water table. Combined, Puna Geothermal Venture’s five production wells normally produce an average of two million pounds of geothermal fluid per hour. Like wells in other volcanic regions (Indonesia, Philippines and Iceland), PGV’s wells are considered prolific in comparison to other types of geothermal wells in the industry.
There are three types of power-generating plants: dry steam, flash steam and binary cycle. Dry steam plants, first used in Italy more than 100 years ago, route the steam directly to a power plant to produce electricity. Dry steam plants are used in places such as The Geysers in California, where steam is close to the surface. Flash steam power plants cause the fluid to rapidly vaporize, driving turbines that in turn drive a generator. Binary-cycle plants are similar and the most advanced. Their closed-loop circulation system means that no excess gases or fluids reach the open air. PGV’s power plant utilizes the closed-loop binary system.