Topping unit at Olkaria IV geothermal power plant, Naivasha, Kenya

Abstract

A study on the optimization of the current set up of Olkaria IV geothermal power plant by utilizing high-pressure fluid is presented. The study is applied on the Olkaria IV geothermal wells to determine the additional electrical energy output that could be generated. A total steam mass-flow of 280 kg/s is passed through a back-pressure turbine acting as a topping unit, operating between 11.8 bar absolute inlet pressure and 6 bar absolute exhaust pressure. Thermodynamic cycle model simulation done using Engineering Equation Solver (EES) shows that 10-26 MW of electricity can be produced in the topping unit assuming turbine isentropic efficiency of 85%. The additional gross power generated will also provide environmental benefits. The application of the proposed model can help to utilize the untapped geothermal energy without, additional drilling costs, thereby increasing the profitability of the operating plants.