Synergetic mechanism of fracture properties and system configuration on techno-economic performance of enhanced geothermal system for power generation during life cycle

摘要

Enhanced geothermal system is one of the most commonly used geothermal power generation systems for hot dry rock. In order to illuminate the life cycle performance, the fracture spacing is coupled with cycle configuration in this study. The typical fracture properties and three enhanced geothermal system configurations are considered, the optimal operating conditions of each system in different periods are obtained, and the techno-economic performance during the life cycle, in 30 years, is compared. The results show that the optimal operating conditions are constantly changing in the life cycle. With the decrease of the geothermal fluid temperature, the optimal evaporation temperature decreases. Double-stage flash system exhibits better power generation performance and techno-economic performance. During the life cycle of double-stage flash system, the net power output decreases 17.41%, while the leveling cost of electricity increases 17.11%. Moreover, the fracture spacing and fracture permeability of hot dry rock have an evident impact on the techno-economic performance and power generation performance. Lower fracture spacing and higher fracture permeability are beneficial for system performance. This study lays a theoretical basis for enhanced geothermal system in engineering applications. (c) 2020 Elsevier Ltd. All rights reserved.