Estimating the technical shallow geothermal potential for heating: A case study of Lörrach, Germany

Abstract

The production of heat accounts close to 50% of global final energy consumption to day and was responsible for nearly one-third of global energy related CO2 emissions. Despite this, the heating sector is often left in the backdrop. But as governments pledge to keep the warming to 1.5◦C and pass ambitious climate laws, there has been a surging interest to decarbonize the heating sector. Heat pumps are touted as an important element in the fight against climate change and towards decarboniz ing the heating sector. The extraction of shallow geothermal energy using borehole heat exchangers (BHEs) is a promising approach for decarbonisation of the heating sector. However, high installation costs and strict regulations often act as barriers. The optimal site-specific system depends on the existing regulations and the local hydeogeological conditions. In this study, a method to estimate the technical potential of shallow geothermal energy for heating BHEs is presented, and the reduction in CO2 emissions that can be achieved by completely tapping this resource is calculated. The method combines the ground thermal properties, estimation of suitable areas for BHE installation and an analytical equation for determining the theoretical geothermal potential in order to estimate the technically available potential. Two scenarios are formulated and compared in order to evaluate the achievable reduction in CO2 emissions. The method is used to provide a first estimate of the technical potential of geother mal energy for heating for a district in south-western Germany. The technical po tential of the district of Lörrach is estimated to be 1.29 TWh, which can cover 40.6% of the total heat demand. The findings further show that geothermal energy has a high decarbonizing potential in the studied region, and switching to geother mal energy for heating can save up 245.22 kton CO2/ year,which is equivalent to more than 50% reduction in CO2 emissions. The work conducted in this thesis can contribute towards the advancement of decarbonisation strategies for the heating sector by providing an estimate on the potential for renewable heat generation from shallow geothermal energy.