Wells can be drilled into the earth to tap this energy. In the form of naturally occurring steam and hot water, geothermal energy can be drawn to the surface to generate electricity, heat and cool buildings, and serve other uses.

• Geothermal energy is heat that flows continuously from the Earth’s interior to the surface—and has been doing so for about 4.5 billion years. The temperature at the center of the Earth is about the same as the surface of the sun (nearly 6,000°C, or about 10,800°F).

• This heat is continually replenished by the decay of naturally occurring radioactive elements beneath the subsurface and will remain available for billions of years, ensuring an essentially inexhaustible supply of energy.

• Geothermal technologies offer many environmental benefits, including:

  • Low emissions from electricity generation. Geothermal power plants largely release only excess steam, with most plants discharging no air or liquid. This makes geothermal power plants a clean source of electricity and an important contributor to the nation’s zero-carbon future. Reaching the levels of geothermal electricity deployment outlined in the GeoVision analysis [energy.gov] could help the United States avoid greenhouse gas emissions equal to the annual emissions of 6 million cars.

  • Critical materials. Some geothermal plants produce solid materials, or sludges, that require disposal in approved sites. Some of these solids are now being extracted for sale (zinc, silica, and sulfur, for example), making the resource even more valuable and environmentally friendly. In addition, lithium—a critical material—is present in high concentrations in some geothermal brines. Learning to cost effectively extract that lithium [energy.gov] could provide the United States with a domestic source of this important material.

  • Efficiency and reduced carbon emissions for heating and cooling. Geothermal energy offers U.S. homes and businesses low-carbon and energy-efficient heating and cooling options, such as geothermal heat pumps [energy.gov], which use the constant temperature of the Earth to regulate heat from buildings. Reaching the target number of installed geothermal heat pumps outlined in the GeoVision analysis [energy.gov] could help the U.S. avoid greenhouse gas emissions equal to the annual emissions of 20 million cars.

  • Comparably low water use. By 2050, geothermal energy could represent 8.5% of total U.S. electricity generation while being accountable for only 1.1% of power-sector water withdrawals. The majority of this growth could be supported using non-freshwater sources.

Geothermal energy is heat that flows continuously from the Earth’s core to the surface—and has been doing so for about 4.5 billion years. This heat is continually replenished by the decay of naturally occurring radioactive elements in the Earth’s interior and will remain available for billions of years, ensuring an essentially inexhaustible supply of energy. Geothermal power plants operate by drawing fluid or steam from underground reservoirs, and these reservoirs have been demonstrated long term at geothermal plants such as Lardarello in Italy (1913), Wairakei in New Zealand (1958), and The Geysers in California (1960).

Some geothermal power plants have experienced pressure and production declines, but operators are finding solutions to maintain reservoir pressure. For instance, the city of Santa Rosa, California, pipes its treated wastewater to The Geysers geothermal field to be used as reinjection fluid, thereby prolonging the life of the reservoir while recycling the treated wastewater.

Geothermal power is “homegrown,” offering a domestic source of reliable, renewable energy.

Geothermal energy is available 24 hours a day, 365 days a year, regardless of weather. Geothermal power plants have a high-capacity factor—typically 90% or higher—meaning that they can operate at maximum capacity nearly all the time. These factors mean that geothermal can balance intermittent sources of energy like wind and solar, making it a critical part of the national renewable energy mix.

Comparably low water use. By 2050, geothermal energy could represent 8.5% of total U.S. electricity generation while being accountable for only 1.1% of power-sector water withdrawals. The majority of this growth could be supported using non-freshwater sources.

District heating systems and geothermal heat pumps can usually be integrated easily into communities, with almost no visual impact. Geothermal power plants tend to have a lower profile and smaller land footprint compared to many other energy-generation technologies, and they do not require fuel storage, transportation, or combustion.

New and different configurations of these systems are emerging in universities and communities all over the United States. Geothermal Technologies Office's (GTO) Community Geothermal Heating and Cooling Design and Deployment [energy.gov] initiative is focused on supporting communities in implementing such systems and will grow the body of replicable case studies to increase deployment nationwide.

GTO is committed to directly engaging with communities [energy.gov] by providing educational services on geothermal energy, empowering them to make informed decisions based on local energy needs.