Geothermal electricity is electricity generated from geothermal energy. Technologies in use include dry steam power plants, flash steam power plants and binary cycle power plants. Geothermal electricity generation is currently used in 24 countries, while geothermal heating is in use in 70 countries.
Estimates of the electricity generating potential of geothermal energy vary from 35 to 2,000 GW. Current worldwide installed capacity is 10,715 megawatts (MW), with the largest capacity in the United States (3,086 MW). El Salvador, Kenya, the Philippines, Iceland and Costa Rica generate more than 15 percent of their electricity from geothermal sources.
Geothermal power is considered to be sustainable because the heat extraction is small compared with the Earth’s heat content. The life cycle greenhouse gas emissions of geothermal electric plants are on average 45 grams of CO
2 per kilowatt-hour of electricity, or less than 5 percent of that of conventional coal-fired plants.