The Altstetten and Höngg energy network is a flagship project for the environmentally friendly energy supply of the future. With its thermal heating and cooling networks, it efficiently supplies entire neighbourhoods and districts with renewable and carbon-neutral energy sources. Join us for the implementation process.
1. Pipeline network on the site of the Werdhölzli sewage treatment plant
The heart of the energy network is located on the site of the Werdhölzlisewage treatment plant. From here, the planned Altstetten North and Höngg transmission grids will be supplied with heat and/or anergy. In order to build the pipeline network on the site of the sewage treatment plant, structural pipe bridges had to be built in places.
(Q4 2019 to Q2 2020)
2. Passing under the Limmat river
For the connection of the Werdhölzli sewage treatment plant to the planned transmission network in Höngg to the north, we created an underground connection between the sewage treatment plant site and Höngg using a wash borehole under the Limmat. This enabled us to connect the pipelines with the future transmission network in Höngg.
(Q4 2019 to Q1 2020)
3. Connection of Höngg to district heating
One of the first sections of road in Höngg to be connected with environmentally friendly heating from the energy network was a section of Frankentalstrasse. The civil engineering works for the energy network were coordinated with other urban construction activities in order to minimise the impact of construction sites on the population as much as possible.
(Q1 2020 to Q3 2021)
4. Connection of large new construction projects
New commercial properties such as the MANUFAKT8048 and Preola were built on a major construction site on Vulkanstrasse. Construction of the Altstetten North transmission network and the connection of the new buildings to the energy network took place at the same time.
(Q3 2019 to Q1 2020)
5. Waste heat extraction from purified waste water
In the waste heat recovery building on the site of the Werdhölzli sewage treatment plant, we extract heat from the treated wastewater before it is discharged into the Limmat. We transfer the heat into a water-powered intermediate circuit, the anergy pipeline network. To make this possible, facilities such as heat exchangers had to be installed in the waste heat recovery building.
(Q3 2020 to Q3 2021)
6. Crossing under the motorway
The area between the motorway and the railway tracks – later also Altstetten Central and South – was to be given access to a transmission network. Coming south from the Werdhölzli sewage treatment plant, we crossed under the motorway using a wash borehole and lay the pipes underground.
(Q4 2019 to Q1 2020)
7. Energy centre in the blower station hall
Our energy centre in the blower station hall of the Werdhölzli sewage treatment plant generates the required heating and cooling. This required, among other things, HGVs to deliver three large energy storage systems and for them to be hoisted next to the building with cranes. Energy storage systems are thermal storage systems filled with water that supply heat to the transmission grid at a later date. The heart of the energy network – a highly efficient large-scale heat pump – was also installed here to harness the heat from the purified wastewater.
(Q4 2019 to Q4 2020)
8. Waste heat extraction from the sewage sludge incineration plant
In addition to the heat from purified waste water, waste heat from the combustion process of the sewage sludge is also utilised. During this construction phase in the energy centre of the sewage sludge incineration plant, we installed heat exchangers, among other things.
(Q1 2020 to Q3 2020)
9. First customer connections
During this construction phase, heating and cooling transfer stations were installed on the customers’ properties and connected to the district heating and cooling network. The first connected properties now had environmentally friendly heating and cooling at their disposal.
(Q2 2020)
10. Swiss Life Arena cooling centre
The high quality of ice required on the main rink resulted in a dense network of cooling pipelines using environmentally friendly ammonia as a refrigerant. To this end,cooling machines and cold and heat storage systems had to be installed in the central cooling system and connected via cooling pipes to form a sophisticated system. The central cooling system of Swiss Life Arena also supplies other buildings with cooling. When completed, around 20 office and commercial properties will be supplied with cooling. This makes it possible to make excellent use of the synergies.
(Q2 2019 to Q2 2022)
11. Connection of the Swiss Life Arena to the energy network
If excess heat results from cooling production, we feed it into the energy network’s anergy grid. The anergy grid transports the heat to the local energy centres within the Altstetten and Höngg energy networks, where it is heated to the required temperature using heat pumps.
(Q1 to Q3 2021)
12. Connection of 35 customers in Höngg
This milestone connected 35 customers, who are renting out several hundred apartments, to the Altstetten and Höngg energy network. The link between the network and the properties’ heating and cooling system is the transfer station.
(2021)
13. Connection of largest customers to the energy network
The largest customer, with around 750 apartments, was connected to the energy network. The link between the network and the properties’ heating and cooling system is the transfer station.
(Q4 2021)
14. Commissioning of cooling network
In the energy centre of the Swiss Life Arena, we generate the cooling for the stadium. At the same time, we are supplying the surrounding office buildings with environmentally friendly cooling from the arena. This ‘cooling hub’ for third parties is an extremely worthwhile solution in view of the growing demand for cooling that is resulting from years of rising summer temperatures.
(Q2 2022)
15. Anergy line to Altstetten East and West energy network
We are developing the new east and west perimeters using a microtunneling process and connecting them to the energy sources of the Werdhölzli sewage treatment plant via an anergy pipeline.
(Since 2023)
16. Connecting up Höngg centre
By connecting central Höngg, we are expanding the supply area of the Altstetten and Höngg energy network. This will allow additional customers to benefit from the environmentally friendly and locally produced heat provided by the energy network.
(from 2023)
17. Creation of Altstetten West energy network
In the energy centre of the Altstetten West energy network, highly efficient heat pumps use environmentally friendly energy from the anergy grid for heat production. The properties in the perimeter of the Altstetten West energy network are supplied with energy for heating via a district heating network.
(From 2025)
18. Creation of Altstetten East energy network
At the energy centre of the Altstetten East energy network highly efficient heat pumps use environmentally friendly energy from the anergy grid to produce heat. The properties in the perimeter of the Altstetten East energy network are supplied with energy for heating via a district heating network.
(From 2024)
19. Development of Altstetten East and West
By connecting Altstetten East and West, we are expanding the supply area of the energy network. This will allow additional customers to benefit from the environmentally friendly and locally produced heat provided by the energy network.
(From 2024)
20. Linkage with Flurstrasse energy network
The Flurstrasse energy network uses waste heat from a data centre as a climate-friendly energy source. The connection to the Altstetten and Höngg energy network enables us to further expand the carbon-neutral heat supply using this additional energy source.
(From 2026)
