The below is a text version of the animation How an Enhanced Geothermal System Works.
A production-injection well is drilled into hot basement rock that has limited permeability and fluid content. This type of geothermal resource is sometimes referred to as "hot, dry rock" and represents an enormous potential energy resource.
Water is injected at sufficient pressure to ensure fracturing, or open existing fractures within the developing reservoir and hot basement rock.
Pumping of water is continued to extend fractures some distance from the injection wellbore and throughout the developing reservoir and hot basement rock. This is a crucial step in the EGS process.
A second production well is drilled with the intent to intersect the stimulated fracture system created in the previous step, and circulate water to extract the heat from the previously "dry" rock mass.
Additional production-injection wells are drilled to extract heat from large volumes of rock mass to meet power generation requirements. Now a previously unused but large energy resource is available for clean, geothermal power generation."