Municipal energy planning focuses on using and expanding energy carriers that require grid-based infrastructure and draw on local energy sources. Suitable areas have been marked on the energy planning map, with energy supply and consumption in the city of Zurich geographically demarcated on thematic maps. We have barely tapped the full potential of using renewables to generate heating and cooling and cut carbon emissions. At present, around 30 per cent of residential areas in Zurich have been developed for thermal grids by municipal utilities companies ewz and Entsorgung + Recycling Zürich (ERZ) as well as private network operators. The plan is to supply around 60 per cent of Zurich’s residential areas with climate-friendly heating and, in some places, with cooling from thermal grids by 2040.
Thermal grids will be built where there are energy sources with significant potential and suitable energy density (demand). Building the infrastructure for thermal grids in each of these areas requires the construction of energy centres and underground transmission lines and the creation of connections to supply individual premises. ewz plans to build new energy networks in areas located in Albisrieden, Altstetten (east), Aussersihl, City, Enge and Höngg (central). These new networks have the potential to help save a total of 52,000 tonnes in carbon emissions every year. By comparison, the Altstetten and Höngg energy network (existing parts and those still under construction) cuts carbon emissions by 30,000 tonnes a year and supplies roughly 30,000 households with eco-friendly heating and cooling.
The city of Zurich has various energy sources with the right potential, such as waste heat from data centres, a waste incineration plant and the Werdhölzli sewage treatment plant and ambient heat from sources such as lake water and groundwater. The new energy networks in the Enge and City districts use lake water. Biomass is set to be used in Albisrieden, and groundwater is expected to be the main heat source for Sihlfeld and the Hardau residential area. Air and woodchips are being tested as additional energy sources. The two energy networks in Altstetten East and Höngg Central are being connected to the existing Altstetten and Höngg energy network, sourcing their energy from the treated wastewater from the Werdhölzli sewage treatment plant.
The City Parliament voted 107 to 14 in favour of the credit facility for the expansion of ewz’s thermal grids on 24 August 2022. The electorate of the city of Zurich will take to the polls on 27 November 2022 to decide on the credit facility totalling 573 million Swiss francs. The proposal put forward for approval by the electorate is as follows:
- A credit facility of 573 million Swiss francs for the expansion of ewz’s thermal grids in the Albisrieden, Altstetten, Aussersihl, City, Enge and Höngg districts. The amount of the credit facility will increase or decrease with changes in the Swiss Federal Statistical Office’s construction price index (price basis October 2021).
- The City Council will decide on how the credit facility will be split into smaller pots for specific projects.
