Maintenance and Operational Experience Gained by Operating the Aluto Langano Geothermal Pilot Power Plant

Abstract

Ethiopia is well endowed with geothermal resources, and current exploration is believed to have studied only a fraction of the ultimate potential. The potential prospective areas are distributed along the Ethiopian Rift valley system which runs in a northeast direction along the entire length of Ethiopia. To begin to realize this potential, in 1998, the Ethiopian Electric Power Corporation (EEPCO) constructed the Aluto Langano geothermal pilot power plant (8.5 MW gross) consisting of two Ormat generating units, one an OEC (Ormat Energy Converter) and the other a GCCU (Geothermal Combined Cycle Unit consisting of a back pressure steam turbine exhausting to an OEC bottoming cycle unit) - each designed to have similar power outputs. The power plant operated satisfactorily for a short period of time right after commissioning before a number of problems arose that severely affected its availability and the power output level. Repair and maintenance of the Aluto Langano GCCU has been completed and the unit was put back into normal operation in July 2007. During the original operational period of the pilot plant and after its recent rehabilitation, experience gained in operation and maintenance will ultimately be used to develop and harness the huge geothermal energy reserve exists in the rift valley region of Ethiopia. In the coming five years it is planned to expand the Aluto Langano geothermal field in two phases.