Recent national focus on the value of increasing US supplies of indigenous renewable energy underscores the need for re-evaluating all alternatives, particularly those that are large and well distributed nationally. A panel was assembled in September 2005 to evaluate the technical and economic feasibility of geothermal becoming a major supplier of primary energy for US base-load generation capacity by 2050. Primary energy produced from both conventional hydrothermal and enhanced (or engineered) geothermal systems (EGS) was considered on a national scale. This paper summarizes the work of the panel which appears in complete form in a 2006 MIT report, 'The future of geothermal energy' parts 1 and 2.In the analysis, a comprehensive national assessment of US geothermal resources, evaluation of drilling and reservoir technologies and economic modelling was carried out. The methodologies employed to estimate geologic heat flow for a range of geothermal resources were utilized to provide detailed quantitative projections of the EGS resource base for the USA. Thirty years of field testing worldwide was evaluated to identify the remaining technology needs with respect to drilling and completing wells, stimulating EGS reservoirs and converting geothermal heat to electricity in surface power and energy recovery systems. Economic modelling was used to develop long-term projections of EGS in the USA for supplying electricity and thermal energy. Sensitivities to capital costs for drilling, stimulation and power plant construction, and financial factors, learning curve estimates, and uncertainties and risks were considered.

No abstract

One of the most prom1 S1 ng techni ques for monitoring the effects of hydraulic stimulation or fracturing is the use of the induced microseismicity to defi ne the shape and ori entati on of the sti mul ated regi ons. The results presented in thi s paper are believed to be the first of their kind with an on-line location system mapping the stimulated zone during injection. The stimulation was undertaken as part of an investigation into the generation of hot dry rock geothermal reservoirs and consisted of a 3.5 million gallon injection at flow rates as hi gh as 40 B/mi n. Many thousands of microseismic events were produced, located and presented as maps to enable the i nterpretati on to 'proceed during the operation. Department of Energy, contract numbers EG-D-2-003-UK(N) and E5A/CON/l15/173/017. The support and encouragement of the staff of these organisations is gratefully acknowledged.The 58 full-time staff working on the Camborne School of Mines hot dry rock geothermal programme have all been i nvo 1 ved in thi s experi ment to some degree and the support and enthusiastic involvement of all the staff is acknowledged.

No abstract

No abstract