Geothermal energy harnesses the continuous heat radiating from the Earth’s core. This thermal energy is brought to the surface by water or steam, which is converted into usable electricity. As a form of renewable power generation, geothermal plants run consistently, independent of weather conditions or time of day. Deployment is concentrated in specific regions where high-temperature resources are naturally accessible. Geothermal power contributes a small, yet steady, fraction to the world’s overall electricity supply.
The Current Global Tally and Installed Capacity
The total count of operational geothermal power plants is typically measured by individual generating units. A recent estimate places the number of individual generating units at approximately 673 operating globally. These facilities are spread across about 35 countries that utilize this resource for electricity generation.
As of the end of 2024, the total installed geothermal capacity across the globe reached approximately 16,873 megawatts (MW). This figure reflects consistent growth, with over 389 MW of new capacity added in 2024 alone. Although distributed across a few hundred units, the electricity generated is substantial, estimated to be around 99 terawatt-hours in 2024.
Geographic Distribution and Leading Producers
The location of geothermal power plants is directly tied to the Earth’s geology, specifically the boundaries of tectonic plates where heat is closest to the surface. Consequently, the majority of geothermal capacity is concentrated in tectonically active zones, such as the Pacific “Ring of Fire.” This geological necessity limits the number of countries that possess the necessary high-temperature resources for large-scale electricity generation.
The United States maintains the largest installed capacity globally, totaling approximately 3,937 MW. Following the U.S., Indonesia is the second-largest producer, with a capacity of about 2,653 MW, due to its location on the Ring of Fire. The Philippines, another nation within this highly active region, holds the third position with 1,984 MW of installed capacity.
Rounding out the top global producers are Türkiye, with an installed capacity of 1,734 MW, and New Zealand, with 1,207 MW. Other significant contributors include Kenya, Mexico, and Italy, each with capacity nearing or exceeding 900 MW. These top countries collectively account for the vast majority of the world’s geothermal electricity production.
Primary Technologies Used in Geothermal Generation
Geothermal power plants employ three technologies to convert the Earth’s heat into electricity, each suited to different resource characteristics. The simplest and oldest method is the Dry Steam Plant, which directly pipes steam from the underground reservoir to spin a turbine. These plants are highly efficient but require a rare resource where steam is naturally present. The first commercial plant of this type began operating in Larderello, Italy, over a century ago.
The most prevalent type of installation is the Flash Steam Plant, which utilizes geothermal reservoirs containing water at temperatures greater than 182°C (360°F). This high-pressure hot water is pumped to the surface and injected into a low-pressure tank, causing a rapid vaporization, or “flashing,” of a portion of the water into steam. This resulting steam is then directed to drive a turbine, and any remaining liquid is typically re-injected back into the reservoir.
For lower-temperature geothermal resources, which are more common, the Binary Cycle Plant is used. This system does not expose the geothermal water to the atmosphere; instead, heat is transferred through a heat exchanger to a secondary working fluid, such as an organic compound with a low boiling point. The moderate heat causes this secondary fluid to vaporize, and its resulting vapor drives the turbine. This closed-loop system allows for the utilization of fluids between 107°C and 182°C (225°F and 360°F).