Geothermal Energy Program Summary Document, FY 1982

Geothermal energy is derived from the internal heat of the earth. Much of it is recoverable with current or near current technology. Geothermal energy can be used for electric power production, residential and commercial space heating and cooling, industrial process heat, and agricultural applications. Three principal types of geothermal resources are exploitable through the year 2000. In order of technology readiness, these resources are: hydrothermal; geopressured (including dissolved natural gas); and hot dry rock. In hydrothermal systems, natural water circulation moves heat from deep internal sources toward the earth's surface. Geothermal fluids (water and steam) tapped by drilling can be used to generate electricity or provide direct heat. Geopressured resources, located primarily in sedimentary basins along the Gulf Coast of Texas and of Louisiana, consist of water and dissolved methane at high pressure and at moderately high temperature. In addition to recoverable methane, geopressured resources provide thermal energy and mechanical energy derived from high fluid pressures, although methane offers the greatest immediate value. Commercial development of geopressured energy may begin in the mid-1980s. Economic feasibility depends on the amount of methane that a given well can produce, a highly uncertain factor at present