• Published



Geothermal energy is thermal heat energy generated from the earth. There are two main categories of energy generation from geothermal resources: hydrothermal and closed loop geothermal systems. The most common use is hydrothermal, where steam produced from reservoirs of hot water sometimes found miles below the earth's surface rotates a turbine that activates a generator to produce electricity.

  • Hydrothermal resources recover heat energy from naturally occurring hydrothermal sources in the earth (e.g., groundwater, rock), typically in the form of hot water or steam.
  • Closed Loop Geothermal Systems make possible the use of alternative heat transport fluids, such as supercritical CO2, that can be used to reduce the power otherwise consumed by pumping water through the system.

USAF Relevance

The Air Force seeks to use geothermal resources to serve an installation or mission's base load to confront the challenge of generating energy inside the installation boundary for extended outages. The Air Force can then use renewable intermittent resources to cover variations and peaks. The fuel supply from geothermal is virtually limitless in these scenarios, so the requirement for fuel storage or reliance on outside entities is non-existent. Although drilling carries an upfront cost and risk that solar and wind do not, new closed-loop technologies that utilize proven lateral drilling technologies open a wider geographic range of viable depth baseload power generation opportunities. these technologies create a subsurface heat source via a "closed-loop" geothermal power technology that eliminates the need for subsurface permeability and large quantities of water. Closed-loop geothermal involves the creation of a sealed well traversing the subsurface rock strata through which heat transport fluid can freely circulate.

Potential Sites

  • FE Warren AFB
  • Mountain Home AFB
  • Joint Base San Antonio