Subglacial groove –a natural heat and cold storage

Heating and cooling the airport infrastructure accounts for by far the largest proportion of Flughafen Zürich AG's own CO2 emissions. Innovative technologies such as energy piles and geothermal probes are already being used in the construction of new buildings to regulate the climate in an environmentally friendly way. By using an underground groove from the last ice age as heat and cold storage, an even more efficient and innovative technology could be used in the future. 

Whether the groove is suitable for storing heat and cold is tested in a multi-stage process. As a first step, seismic investigations were carried out. This allowed the groove depth, shape and rough layer structure to be mapped. Additional exploratory drilling at three locations confirmed the initial findings and provided promising additional information about the groove: It carries gravel and water and therefore fulfills the requirements of potential heat and cold storage. The next step was the construction of a test well between the P6 parking garage and the OPC 4 freight building in 2024. This will provide information about what quantities of water can be pumped,  the flow rate and chemical composition of the water. Finally, there will be the construction of a second well in order to enable circulation tests. The results will determine where the definitive wells for pumping and returning the groundwater will be located and how many of them will be needed to use the channel as an efficient storage. If successful, Zurich Airport will be able to use the groove as a heat and cold storage facility from 2027 on.

Regardless of the extent to which the groove can ultimately be used as a heat and cold storage for the airport, the current investigations are valuable and provide important new insights into the structure and groundwater of such deep grooves and their development. All the findings will be provided to the scientific community and can thus contribute to research into emission-free cooling and heating systems. The project is being funded by the Swiss Federal Office of Energy (BFE) as a pilot project for geo-energy with a maximum of CHF 1 million.