city of Zurich
The milestones provide an overview of the planned and realised construction projects for the city of Zurich’s climate-friendly heat supply transformation. They point to important political decisions taken as a result of referendums.
The Altstetten and Höngg energy network is one of the projects with a showcase impact far beyond Switzerland’s borders. In its final state, slated for completion in 2032, the network will supply around 30,000 households with climate-friendly heating and, in some cases, cooling. To this end, the future energy centres in Herrlig and Rautistrasse will be connected via underground anergy pipes installed by way of a microtunnel.
Information to follow
Building for the future is underway at Basteiplatz square. In an initial phase until 2025, ewz will create here the access point for the small microtunnel, which will run to the target excavation pit near Bürkliplatz square. The aim of the tunneling is to connect the existing Fraumünster lake heat network with CoolCity in the future. Upon completion, CoolCity will supply approximately 500 buildings in the supply area with heating and cooling from the lake water.
By 2027, around 120 properties in the popular Seefeld residential and business district will be connected with renewable heating and cooling. The Riesbach energy centre in the EB Zurich cantonal vocational adult education school is at the heart of this network and is due to be commissioned in summer 2024.
An innovative solution for a comprehensive heat supply system with lake water was found by sinking the pumps into the lake. This made it possible to expand the Fraumünster lake heat network to supply the Zurich Stadthaus, Bellevue buildings and other properties on Fraumünsterstrasse and Paradeplatz/Bahnhofstrasse. The Fraumünster church also benefits from the sustainably produced heating and cooling.
With the reopening of the Convention Center, the energy centre for the Escherwiese lake heat network was also put into operation. In addition to the Convention Center, this supplies the Park Hyatt hotel and various other office buildings on Bleicherweg and Claridenstrasse with environmentally friendly heating and cooling. Lake water from a depth of 12 metres is used as the energy source for the combined heat pumps and cooling machines and is transported via a 250-metre pipeline to the energy centre in the Convention Center.
The Altstetten and Höngg energy network is a flagship project for the environmentally friendly energy supply of the future. For the connection of the Werdhölzli sewage treatment plant to the planned transmission network in Höngg to the north, an underground connection was created between the sewage treatment plant site and Höngg using a wash borehole under the Limmat river.
From January 2025, ewz will take over ERZ’s district heating regions, creating the largest district heating network in Switzerland. The renewable energy sources include lake water, wood and waste heat from sewage treatment plants and waste incineration plants.
From January 2025, ewz’s district heating network in the city of Zurich will cover around 250 km.
By 2040, ewz’s district heating network in the city of Zurich will grow to around 400 km.
At ewz, more than 7,500 properties are currently connected to the district heating network in the city of Zurich.
Today, district heating networks cover a good third of the city of Zurich – with that figure expected to rise to around 60% by 2040.
The history of district heating goes back a long way. As early as in the 1970s, waste heat from waste incineration was used in the city of Zurich. Since 2000 , we have been supplying district heating from renewable sources, such as lake water and waste heat from treated wastewater. Today, district heating networks cover a good third of the city of Zurich – with that figure expected to rise to around 60% by 2040.
Use the district heating information tool (in German) to check whether connection to a district heating network is possible. There is no requirement to connect. Find out more about our heating network solutions.
District heating is infrastructure that supplies thermal energy to several buildings on different plots of land. This is transferred as water or steam in insulated pipelines from one or more energy centres (generators) to the connected buildings (consumers). Thermal network, district heating/cooling network and energy/heating network are related terms. District heating networks can be supplied from various sources and, depending on the design, offer the option of supplying buildings with heating and cooling.
By using locally available renewable energy sources, you’re helping to reduce CO₂ emissions. In addition, you’re meeting current and future energy policy requirements. One possible source is waste heat from sewage treatment plants or technical facilities such as data centres. In addition, wood, groundwater and lake water can be used as sources of heating and cooling for thermal networks. All of these energy sources are renewable and locally available, so they don’t have to be imported.
