| Abstract |
Information is provided on the status of geothermal direct heat utilization in the United States, with emphasis on developments from 1985 to 1990. A total of 452 sites, which include approximately 130,000 individual installations, have been identified with an annual energy use of 19.7 x 10/12 kJ. Approximately 44% of this use is due to enhanced oil recovery in four Midwestern states, and 30% is due to geothermal heat pumps. Since 1985, 25 new projects, which include approximately 200 individual installations, and representing a thermal capacity of 106.7 MWt and annual energy utilization of 1.1 x 10/12 kJ, have become operational or are under construction. Earth coupled and groundwater heat pumps, representing the largest growth sector during this period, add an additional 400 MWt and 1.2 x 10/12 kJ to these figures. Geothermal heat pumps have extended geothermal direct heat use into almost every state in the nation. Slightly over 200 direct heat geothermal wells, averaging 150m in depth, along with approximately 30,000 heat pump wells, have been drilled for these projects. Between 20 and 25 professional man years of effort are estimate to have been allocated to geothermal direct heat projects during each of the five years. |