The geothermal energy stored within the interior of the earth amounts to a significant quantity which, if fully exploited, could supply the energy needs of man for a millennia. Low temperature hydrothermal resources underlie vast areas of the United States as illustrated on Figure 1, particularly in the western half of the country. The U.S. Geological Survey has identified 1,346 hydrothermal convection systems of which 1,294 have temperatures less than 300°F and are considered suitable for direct heat applications (Reed, '1983). Resource temperatures greater than 300°F are considered economic for electrical generation. Quantitative estimates of identified low and intermediate temperature (less than 300°F) geothermal systems contain 68.3 million billion Btu's of beneficial heat for 30 years