Life cycle assessment of shallow to medium-depth geothermal heating and cooling networks in the State of Geneva.

• Shallow and medium geothermal systems are underrepresented in life-cycle assessments. • The life-cycle environmental impacts of geothermal heating and cooling are analyzed. • Geothermal heating and cooling are fit for decarbonization of the building sector. • Most other impacts are lower than for fossil fuels, except for mineral resource scarcity. • Decentralized connected heat pumps have lower impacts than district heating. Geothermal heating and cooling from a depth of 10–3′500 meters have considerable decarbonization potential but understudied life-cycle environmental impacts. We quantified the life-cycle impacts of six heating and cooling configurations from shallow to medium-depth geothermal wells with connected, decentralized heat pumps and district heating and cooling in the State of Geneva. Shallower systems with connected heat pumps have better environmental performance than systems with district heating, whereas shallow systems with free cooling perform best for cooling. These environmental impacts are lower than those of fossil fuels, except for mineral resource scarcity, especially with decentralized heat pumps and free cooling. [ABSTRACT FROM AUTHOR]