Enhanced geothermal systems (EGS), or human-made geothermal energy, holds the potential to power more than 65 million American homes and businesses, and is the next frontier for renewable energy deployment. The Geothermal Technologies Office (GTO) EGS program supports research, development, and demonstration projects that guide enhanced geothermal technologies towards commercial viability.
A naturally occurring geothermal system, known as a hydrothermal system, requires three key elements to generate electricity: heat, fluid, and permeability, which is when fluid can move freely through the underground rock.
In many areas, however, the underground rock is hot but there is not enough natural permeability or fluids present. In those cases, an enhanced geothermal system (EGS) can be used to create a human-made reservoir to tap that heat for energy.
In an EGS, fluid is injected deep underground under carefully controlled conditions to create new fractures and cause pre-existing fractures to re-open, creating permeability. Increased permeability allows fluid to circulate throughout the more fractured hot rock, and the fluid becomes hot as it circulates. Operators pump the hot water up to the surface, where it generates electricity for the grid. Watch a video to learn more about the steps and benefits in EGS development.
EGS could facilitate geothermal development beyond traditional hydrothermal regions, thereby extending geothermal energy production nationwide. EGS advances are being demonstrated worldwide today, in both the public and private sectors.