Supply Characterization of Geothermal District Heating and Cooling Applications in United States

Abstract

This paper is an update of an earlier supply analysis [He, et al., 2013] of low-temperature utilization of geothermal resources using geothermal district heating and cooling systems. Along with the use of identified hydrothermal resources, it updates the supply curve for direct-use utilization using undiscovered hydrothermal resources and near-hydrothermal EGS resources. It also incorporates an improved design of the heating system, so that the energy production of the system matches the continuously changing energy demand due to changes in the ambient temperature. Due to uncertainties in characteriz-ing the geothermal reservoir and the related costs, Monte Carlo simulations are used for both the estimates of thermal potential and levelized cost. The thermal potential of identified hydrothermal resources is identified with a mean of 72,577 MWth, with a lowest cost at $6.74/MMBtu, while that of the undiscovered hydrothermal resources has a mean of 240,860 MWth, with a lowest cost at $7.25/MMBtu. The thermal potential of near-hydrothermal EGS has a mean of 41,035 MWth, with a lowest cost at $7.87/MMBtu. At last, sensitivity analyses are conducted to target the metrics with the most effective influence in decreasing the levelized cost of such applications.