caption: "Diagram showing how electricity is generated in a vapor-dominated hydrothermal system. Steam is used directly from the wells to drive a turbine generator. Wastewater from the condenser is injected back into the subsurface to help extend the useful life of the hydrothermal system."
Wendell A. Duffield and John H. Sass
2003
"Geothermal Energy-Clean Power from the earth's Heat", USGS Circular 1249, p.11.