Which conditions are needed for a geothermal reservoir to produce electricity?

To produce electricity, a geothermal reservoir must meet several specific physical and geological conditions to be considered viable for power generation:

• Heat Source: The reservoir requires a high thermal gradient, typically found in regions of recent volcanism, along tectonic plate boundaries, or near crustal "hot spots".12
• Temperature: For economical electricity production, reservoirs generally require water temperatures of at least 175 °C (347 °F), though specialized binary cycle technologies can utilize lower-temperature sources.34
• Permeability and Recharge: The reservoir must have adequate permeability—often provided by faults or fractures—to allow fluids to circulate and rise toward the surface. It also requires sufficient water recharge to maintain the supply.12
• Containment: An impermeable caprock is necessary to trap the heat and prevent it from escaping to the surface.1
• Accessibility: The resource must be economically reachable via drilling, typically within the range of current drilling technology.1

In areas lacking natural permeability, enhanced geothermal systems (EGS) can be used to artificially create a fracture system in hot dry rock, allowing for heat extraction.32