Supply Analysis of Geothermal District Heating and Cooling Application in United States

Abstract

This paper focuses on the approach to characterize the supply curve of geothermal energy for district heating and cooling system in the U.S. It estimates the thermal potential from identified, undiscovered hydrothermal resources, and near-hydro EGS resources. The thermal potential of the identified hydrothermal resources is estimated with a mean of 72,577 MWth, with a lowest cost at 6.74 $/MMBtu. That of the undiscovered hydrothermal resources is with a mean of 240,860 MWth, with a lowest cost at 7.25 $/MMBtu, and that of the near-hydrothermal EGS is 41,035 MWth, with a lowest cost at 7.87 $/MMBtu. An Excel-based model is developed to estimates the levelized cost of the geothermal district heating and cooling (GDHC) system corresponding to each resource. Several technical or economic inputs from the cost model are selected for sensitive analysis. The system’s energy demand shows the most negative influence on the levelized cost, while the drilling cost shows the most positive influence. And increasing the energy demand is the most effective way to decrease the levelized cost. The supply curve indicates that the economical sites for the GDHC system are concentrated in western U.S. With over half of the low-cost identified hydrothermal energy has already been used for other applications such as geothermal power generation, it is worth considering the near-hydro EGS resources due to its acceptable levelized cost. Besides, there are another 150,000 MWth of the undiscovered hydrothermal energy with levelized cost lower than 30 $/MMBtu can also be used.