Evaluation of the Shallow Geothermal Potential for Heating and Cooling and Its Integration in the Socioeconomic Environment: A Case Study in the Region of Murcia, Spain

Abstract

[EN] In order to boost the use of shallow geothermal energy, reliable and sound information concerning its potential must be provided to the public and energy decision-makers, among others. To this end, we developed a GIS-based methodology that allowed us to estimate the resource, energy, economic and environmental potential of shallow geothermal energy at a regional scale. Our method focuses on closed-loop borehole heat exchanger systems, which are by far the systems that are most utilized for heating and cooling purposes, and whose energy demands are similar throughout the year in the study area applied. The resource was assessed based on the thermal properties from the surface to a depth of 100 m, considering the water saturation grade of the materials. Additionally, climate and building characteristics data were also used as the main input. The G.POT method was used for assessing the annual shallow geothermal resource and for the specific heat extraction (sHe) rate estimation for both heating and, for the first time, for cooling. The method was applied to the Region of Murcia (Spain) and thematic maps were created with the outputting results. They offer insight toward the thermal energy that can be extracted for both heating and cooling in (MWh/year) and (W/m); the technical potential, making a distinction over the climate zones in the region; the cost of the possible ground source heat pump (GSHP) installation, associated payback period and the cost of producing the shallow geothermal energy; and, finally, the GHG emissions savings derived from its usage. The model also output the specific heat extraction rates, which are compared to those from the VDI 4640, which prove to be slightly higher than the previous one.