On the Thermodynamic and Economic Performance of Binary Power Plant Configurations for the Exploitation of Two-Phase Geothermal Resources

Abstract

Historically, power generation from two-phase and liquid-dominated geothermal resources has been confined to direct steam cycles and binary cycles respectively. Binary cycles tend to provide a number of operational advantages over direct steam cycles, particularly with regard to the surface handling and reinjection of co-produced high Global Warming Potential non-condensable gases. However, the design of geothermal power plants for two-phase resources is a demanding task; different technologies, plant configurations and working fluids must be considered, and the optimum plant design is strongly dependent on the geofluid conditions and composition. Moreover, the impact and cost of handling and reinjecting non-condensable gases must be accounted for. This study investigates the thermodynamic and economic performance of novel binary ORC power plant configurations specifically for two-phase geothermal resources to establish s against the more commonly adopted flash power plants. A parametric study on the geofluid inlet conditions and NCG content, as well as considering different NCG handling scenarios is carried out to compare their performance and define the optimum application envelope of the different technologies.