With an end to the age of cheap fossil fuels in sight, interest in alternative energy sources has undergone a revival. Geothermal power, defined as the generation of electricity from the large amount of heat available in the earth’s crust, represents one of the most important renewable energy resources (Flynn 1997) in light of its economy, low environmental impact and ready availability.
This thesis, undertaken in association with the Energy Systems division of “Downer”, firstly provides a summary of geothermal technology covering issues of its nature and occurrence, historical development, exploration and site selection, plant operation, environmental impact and financing.
Secondly, a case study determining the most suitable plant configuration in terms of potential power production and economic return, is performed. A performance map in terms of gross power output is formulated across the range of available wellhead conditions, an optimal cycle configuration identified for each of the six different cycles, and plant capital cost and generated return calculated for a 15- year life cycle. This analysis identifies a double flashing plant (with separation and flash tank at 9 and 6 bar respectively) with a condensing cycle as the most suitable cycle for the specific wellhead data, considered representative of a typical, high output, two-phase fluid, geothermal well from New Zealand’s Taupo Volcanic Zone.
Finally, a summary and appraisal of current Australian geothermal status and resources is provided.