| Abstract |
A geothermal power station utilising a low temperature geothermal resource was established with the assistance of the United Nations Development Program (UNDP) in Nagqu Town in the Tibet Autonomous Region of the Peoplesí Republic of China in 1993. Due to the need to maintain the geothermal fluid at reservoir pressures in order to prevent calcite scaling, downhole pumps were utilised to pump the well fluids to the binary power plant heat exchangers. However, this proved to be inappropriate technology and by December 1994, both downhole pumps had failed and the plant became idle. In 1997, the UNDP embarked upon a programme to recommission the Nagqu Geothermal Power Station. In order to control the calcite scaling, it was proposed that antiscalant injection would be used to replace the downhole pumps. Associated modifications to the steamfield facilities would also be necessary. The power plant was successfully re-commissioned on 26 August 1998, although not all of the steamfield modifications had been fully implemented by that time. However, the failure of certain vital components has continued to plague the plant, and the difficulty experienced by the plant operating company to procure replacement parts has seriously affected the plant operation since re-commissioning. It is understood that as of August 1999 the plant was idle, waiting on spare parts. With such a poor operating history, the Nagqu Geothermal Power Station cannot be regarded as a successful project, and this view is shared by the UNDP. However, the fundamental reasons for establishing a geothermal power plant at Nagqu are sound. There was an acute need for energy (electricity and heat) required to advance the development of an isolated region in a rigorous climate, and the desire to utilise an indigenous resource was logical. Unfortunately, in this case, the combination of factors such as a difficult resource, an arduous environment, lack of facilities, trained workforce and technical skills, and geographical isolation have all worked against the project. The challenge for the future is how to turn projects such as this one, with all of its attendant difficulties, into successes, in order that geothermal energy can make significant contributions to the development of economic and human resources by helping to solve energy shortages. |