Performance Investigation of Geothermal Power Plant Based on Exergy and Exergoeconomic Analyses (Case Study: Sarulla Geothermal Power Plant)

Abstract

The analyses of exergy and exergoeconomic calculations have been carried out at the Sarulla Geothermal Power Plant (SGPP) unit 1 which has a capacity of 110 MW. The evaluation and modelling process uses Engineering Equation Solver (EES) software commercial version v9.430. This research was conducted to identify exergy lost in certain components to provide suggestions for further development. Both energy efficiency and exergy are calculated based on the thermal fluid flow process on the SGPP. The calculations showed that energy efficiency for Ormat Energy Converter (OEC) Brine, OEC Bottoming, and overall SGPP are obtained in the amount of 13.4%, 7.67% and 10.57%, respectively. Meanwhile, efficiency exergy of OEC Brine, OEC Bottoming, and overall SGPP were obtained respectively at 38.94%, 33.51% and 39.97% with each exergy destruction flow rate at 32,935 kW, 34,726 kW, and 1,644,686 kW, respectively. The highest exergy destruction was obtained at reinjection wells of 58,263 kW, around 21.25% of the production wells exergy. Exergoeconomic analysis was also carried out through consideration of capital costs. The ratio of exergy and energy lost to capital costs is 6.14 Watt/US $ and 0.29 Watt/US $