Energy, Exergy, Economic, and Environmental Analyses (4E) of Geothermal Power Plant With Double Flash System for Power and Heat Production

Abstract

Geothermal energy is a reliable and sustainable renewable energy source due to its continuous availability and eliminating the need for energy storage systems. Among various types of geothermal power plants, double flash (DF) geothermal plants are among the most widely utilized. This paper presents a comprehensive thermodynamic analysis of a DF geothermal power plant, integrating energy, exergy, economic, and exergoenvironmental (4E) evaluations. The study examines the influence of key parameters, including the high-pressure separator and geothermal production well temperature, on the system performance. The results indicate that the expansion valve of the high pressure separator exhibits the highest exergy destruction rate (EDR) followed by the steam trubine, while both high- and low-pressure separators experience no exergy destruction. The energy and exergy efficiencies are found to be 13.3% and 51.23%, respectively. The condensation heat rate is obtained around 46.551 MW, suggesting potential use for district heating applications. Additionally, the findings demonstrate that increasing the geofluid source temperature and the pressure of high-pressure separator 1 lead to a decrease in the unit exergy cost, but an increase in overall cost rate, highlighting important trade-offs for optimizing plant performance.