Rehabilitation of the Aluto Pilot Geothermal Power Plant

Abstract

The Aluto Pilot Geothermal Power Plant was built and commissioned in late 1998 but stopped operation after a very short period due to various technical problems. Failure of the heat exchanger tubes caused the premature shutdown of the OEC unit after about a year of operation. A number of resource related problems also caused reduction in the power output of the GCCU which was eventually shut down in 2002. The rehabilitation of the plant began in early 2006 which included overhaul of the wellhead valves, inspection of the steam turbine rotor and bearings, testing and identifying failed tubes of the OEC heat exchangers and rectifying plant PLC control system. Significant work was carried out during 2006 and 2007 which resulted in the GCCU unit becoming operational in June 2007. Failure analysis of the OEC heat exchanger tubes revealed that they need to be replaced with more corrosion resistant material. Subsequently, retubing of the heat exchanger tubes was undertaken in early 2009 and the unit was commissioned in June 2009. Both of the Aluto power plant units have been under operation since commissioning.