Technical and Economic Analysis of a Geothermal District Heating Plant for a Sustainable Community in Helena, MT
Researcher: Daniel Scott
Principal Investigator: Professor Jefferson Tester
A study is being undertaken into the technical and economic feasibility of a geothermal district heating system for the proposed sustainable community of Aspen Trails in Helena, MT. A preliminary design and economic analysis has been undertaken of the system to assess the feasibility of the proposed system. Heating demand analysis has indicated that 4.04 x 1013 J/yr is required by the community, which has a population of 1943 people. After some analysis of well temperature data, a site at Broadwater, 11 km to the southwest of Aspen Trails, has been identified as an ideal location for the geothermal wells to be located. The wells should be 1.28 km deep and have been sized to supply the community's heating demand for a lifespan of 100 years. An engineers estimate of the installed cost of the system indicated that the total cost would be $7.2 MM with an annual operating cost of $143 M. An economic model has been developed based on offset costs from the traditional natural gas usage by the community. It is anticipated that the financing would come from a contribution from the sale of each house and a low interest loan, as well as possible tax incentives. A normalized cost of heat has been calculated to be $7.80/MMBTU, based on an undiscounted 50 lifespan.