Zürich Airport in Switzerland is investigating whether a subglacial groove 300m below the airport surface could serve as a heat and cold storage to heat and cool a proportion of the airport buildings without emitting CO2 emissions.
This initiative forms part of the airport’s goal to reach net-zero emissions by 2040. According to the airport, heating and cooling the airport infrastructure accounts for the largest proportion by far of Zürich’s own CO2 emissions. If successful, Zürich Airport could be able to use the channel in 2026.
The airport estimates the investment costs for researching the channel and building the wells at between CHF4m (US$4.6m) and CHF8m (US$9m) – depending on the number and locations of the wells, alongside costs for pipelines and other technical measures. The project is being funded by the Swiss Federal Office of Energy (BFE) as a pilot project for geo-energy with a maximum of CHF1m (US$1m).
The team at Zürich Airport worked with IG Rinne, a consortium consisting of engineering consultants at Geo Explorers, Sieber Cassina & Partner and E-Axiom, to develop the multi-stage analysis process. The team started with seismic investigations. This enabled the channel 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 is up to 1km wide and around 30km long. The key factor, however, is its composition. The channel carries gravel and water and therefore fulfills the requirements for potential heat and cold storage. Excess heat from the summer can be stored in water-bearing gravel and taken out again for heating in the winter. In turn, the buildings can be cooled in the summer.
The next step is to construct a test well. Among other things, this is to show what quantities of water can be pumped, and what the flow rate and chemical composition of the water are. This in turn will determine where the final wells for pumping and returning the groundwater could be located and how many of them would be needed to use the channel as an efficient storage. If too many wells are required, Zürich Airport would not be able to implement the project to full effect. However, the airport has reported that the results of the explorations to date are promising. Regardless of the extent to which the channel 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 channels and their development.
Lydia Naef, chief real estate officer at Zürich Airport, said, “By moving away from fossil fuels such as oil and gas, we are making significant progress toward our goal of achieving zero greenhouse gas emissions by 2040. Geothermal energy plays a key role in this. We are already using innovative technologies such as energy piles and geothermal probes for environmentally friendly climate control when constructing new buildings.”
Emanuel Fleuti, head of sustainability and environment at Zürich Airport, said, “The project is being funded and supported by the Swiss Federal Office of Energy as a pilot project. We are making all the findings available to the scientific community and can thus contribute to research into emission-free cooling and heating systems.”
Dominik Zimmermann, project leader of Energy 2040 of Zürich Airport, is part of the team responsible for decarbonizing the airport infrastructure. In the video below, he explains the function of the channel in reducing the airport’s CO2 emissions to net-zero emissions by 2040.
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