美国地热概述.ppt

A New Look at Geothermal Energy as an Energy Choice for the Future W.D. Gosnold, D.F. Merriam, D.D. Blackwell Outline Take home message Geothermal energy overview What we thought we knew What has changed What we now know Take Home Message Geothermal energy is an underestimated and largely untapped resource that could have a significant impact on the world’s energy future. Advances in technology make electrical power generation from low-to-intermediate temperature geothermal waters a reality. The power that could be generated from oil field waste waters alone is enormous. Combining all potential geothermal resources could supply all electrical power needs for the US. The first coordinated assessment of US geothermal resources involved: US Geological Survey Circular 726 (1975) Circular 790 (1979) Circular 892 (1983) DOE - State Coupled Program Geothermal resource maps and reports Industry Working power plants Universities SMU, Utah, OIT, MIT, Va Tech, Nebraska, UND, UK, NMSU Establishment of laboratories and many publications Professional Organizations Geothermal Resources Council Some key definitions The temperature scheme established by the U.S. Geological Survey Circular 726 (White and Williams, 1975) categorized hot water resources as: high-temperature (150°C) intermediate-temperature (150°C to 90°C) low-temperature (90°C) Types of Geothermal Systems Hydrothermal systems Conduction dominated systems Stratabound systems Geopressured systems Engineering enhanced geothermal systems (EGS) Ground source heat pump Geothermal Applications Direct use heat Electrical power Ground source heat pumps Direct Use  Space heating Aquaculture Greenhouses Industrial processes Although the potential for energy production from low to intermediate resources is great, actual usage has been slow to develop. Lund and Boyd (2000) estimated that direct heat applications in the United States are 8.478 EJ y-1 (8,044 billion btu y-1). The accessible resource in sedimentary