Dieng geothermal power plant is one of the Geothermal plants located in Indonesia with a total estimated potential of 400 MWe. The reservoir is characterized by water-dominated with 240 to 333°C temperature. Recently, the company operated one unit of single-flash system with a capacity of 60 MW. To improve its capacity, unit expansion of unit 2 and 3 are designed with each capacity of 60 MW. Apart from this expansion, another effort is optimizing the existing plant. It can be conducted with a thermodynamic approach using energy and exergy analysis. Therefore, this study aims to evaluate and optimize the existing geothermal power plant using energy and exergy analysis. With the latest data obtained, the results show that the exergy value of production wells is around 106,515 kW. The electricity production with the system is around 40,680 kW, resulting in an exergy efficiency of about 38.19%. Furthermore, the optimization is carried out on the turbine because it shows the greatest irreversibility of 11,217 kW. Optimization is done by varying the incoming turbine pressure. These results indicate that higher inlet pressure increases irreversibility and lowers energy efficiency. Furthermore, the optimum inlet turbine pressure is achieved at 5.5 bar with the maximum change depending on the ambient temperature.

Dieng 地热发电厂是位于印度尼西亚的地热发电厂之一，总估计潜力为 400 兆瓦。水库以水为主，水温240～333℃。近期，该公司运行了1台容量为60兆瓦的单闪系统。为提高产能，2、3号机组分别设计扩容60MW。除了此次扩建，另一项努力是优化现有工厂。它可以通过使用能量和火用分析的热力学方法进行。因此，本研究旨在利用能源和火用分析来评估和优化现有地热发电厂。根据获得的最新数据，结果显示生产井的火用价值约为 106,515 kW。该系统的发电量约为 40,680 千瓦，导致火用效率约为 38.19%。此外，优化是在涡轮机上进行的，因为它显示了 11,217 kW 的最大不可逆性。优化是通过改变进入的涡轮压力来完成的。这些结果表明较高的入口压力会增加不可逆性并降低能效。此外，最佳进气涡轮压力达到 5.5 bar，最大变化取决于环境温度。