Prefeasibility Design of Single Flash in Asal Geothermal Power Plant 2x25 MW, Djibouti Republic

Abstract

Geologically, the most active structure in Djibouti is Asal area. Six wells have been drilled with various depths ranging 1137 to 2105m. The first two wells have been drilled in 1975 and the four others in 1987 to 1988. Well Asal-2 was damaged and the temperature of other wells varies between 260 to 360°C. In spite of the significant geothermal studies and the deep drilling explorations conducted since 1970 on several geothermal prospect zones, the geothermal energy in Djibouti is still to be developed. But actually, the priority is to develop a new power plant by using the steam resources from the wells are underway. The main objectives of this paper are to design a prefeasibility geothermal power plant with a total net output power that is 2x25 MWe. The modelling and the simulation of the model consist to observe the performance of the system when some inputs (Wet-bulb temperature, cooling water supply system, etc…) conditions change. And to determine also the optimum and adequate pressure for the technical operation of the system and optimize the electrical power production process. The simulation and technical analysis using EES program has proven very useful for calculations giving the turbine power output 55.6 MWe and the power plant’s electrical consumption as approximately 7.2% of the power from the turbine.