Medium-Low-Enthalpy Geothermal Power-Electricity Generation at Gonghe Basin, Qinghai Province

Qinghai Province is characterized by relatively abundant geothermal resources in China, but geothermal energy utilization has been suffering from low efficiency due to the dominant direct use over a long period. Taking Gonghe Basin located in northeastern Qinghai as the study area, we explore the issue in this paper on the basis of the previous geothermal geological and geophysical investigations. A borehole (DR2) with a depth of 1 852 m in the north part of the basin is drilled and geothermal fluid with a temperature up to 84.2 ℃ can be extracted from DR2, based on which the first geothermal power plant in Qinghai with an annual net electricity generation capacity of 114 kW is established. Different from the Yangbajing geothermal power plant in Tibet where high-temperature geothermal fluids are exploited for electricity generation, the Gonghe pilot power plant in Qinghai is a typical example of middle-low-enthalpy geothermal power generation, which leads the optimization of energy structure in Qinghai Province. In general, the geothermal fluids from Gonghe are featured with comparatively high temperatures and discharge rates, and therefore have a great potential for power generation. However, scaling may occur during the exploitation of Gonghe geothermal fluid in view of its chemical composition, which should be addressed in the process.