Pratiwi, Astu Sam; Trutnevyte, Evelina

Strategies to decarbonize the building sector increasingly include geothermal heating and cooling, which are often applied in networks to benefit from the economies of scale. We conducted a prospective study of the life-cycle environmental impacts of geothermal heating and cooling networks in the State of Geneva, Switzerland, focusing on global warming, particulate matter emissions, terrestrial acidification, fossil and mineral resource scarcity, water consumption, land use, and total energy demand. We constructed six options for developing geothermal district heating and cooling by combining geothermal resource at a shallow or medium depth (10-3’400m) with both centralized and decentralized networks. The options were first analyzed for the cases where heating and cooling are entirely supplied by geothermal resources. Further, a bounding analysis was used to estimate the lower and upper bounds of the environmental impacts under uncertainty. Finally, these impacts were compared with those of other heating and cooling technologies that are used in the State of Geneva. Our results show that, while most analyzed environmental impacts of geothermal heating and cooling networks are lower than those of fossil fuel-based systems, the impacts on mineral resource scarcity are higher. This finding is specific to the State of Geneva, where hydropower constitutes a large share of the electricity mix. On the other hand, the overall environmental impacts of geothermal heating and cooling networks highly depend on the type of supplementary heating and cooling resources that are used for the integration of geothermal energy.