And at the Dübendorf site?
Here we are using more and more waste heat and have invested quite a lot in recent years to further optimise the system. On the one hand, heat is recovered locally in the buildings from the exhaust air of the offices or from the central compressed air system. On the other hand, there is a district heating network on the Eawag and Empa campus, which all buildings are connected to. The waste heat from the refrigeration machines and freezers, for example, is fed into this network and can be used for heating by means of a heat pump. However, the waste heat cannot be stored at the moment. But that will change with the geothermal probe that is currently being built on the Empa site.
How will this geothermal probe work?
It will serve as seasonal storage. This means that the waste heat that is not needed in the summer can be stored in the ground via the probes and then used for heating in the winter. This will make it possible to use a much larger proportion of the waste heat in future. The rest of the heat demand will still be covered by gas heating, but this portion will then be significantly smaller. In 2021, 13% of the gas demand for building heating at Eawag was covered by certified biogas.
“With the geothermal probe currently under construction, it will be possible to use a much larger proportion of the waste heat in Dübendorf in the future.”
Since 2020, in accordance with federal requirements, all federal institutions, including Eawag, must be climate neutral in the building sector. This means that the CO2 emissions that we cannot avoid must be compensated. However, our objective is of course to avoid as many emissions as possible instead of just compensating for them and, for example, to be able to cover the entire remaining gas demand with biogas in future.
Are there other topics the environmental team is working on besides the central topic of energy/greenhouse gas emissions?
Yes, biodiversity is also an issue. The Eawag campus in Dübendorf is already doing very well in this respect, with many wildflower meadows, some alternating wetland sites near the aQa restaurant, the renaturalised Chriesbach stream and a naturalised area with hedges and small structures between the experimental ponds and the laboratory building. This creates a continuous green zone from the main road to the railway line. We would therefore like to have the entire Eawag site in Dübendorf certified by the Nature & Economy Foundation this year. This foundation promotes nature in urban areas and awards exemplary sites in this respect. When Empa’s new multi-storey car park is completed, many parking spaces on the campus can also be removed. These spaces will be used to create a new, near-natural green belt connecting Empa and Eawag.