Vienna’s district heating will be powered by waste water

The new large scale heat pump will be able to supply more than 100,000 homes with warmth

Last week, authorities in Vienna announced the construction of a new sewage water heat pump capable of powering more than 100,000 households. The first stage of the project is set to complete in 2023 and it is able to produce 55 megawatts from wastewater, the equivalent of heating 56,000 households. According to authorities, the plant will be complete in 2027, with a capacity to produce 110 megawatts of energy, powering around 112,000 households.

When fully complete, the project will cost 70 million euros and is expected to save the city around 300,000 tons of CO2 annually. It is also expected to greatly increase the share of Vienna’s district heating powered by renewable energy.

Waste heat – the promise of reducing carbon emissions

The new large scale wastewater heat pump in Vienna will be powered by renewable energy from the nearby hydropower plant in Freudenau. At the same time, it will capitalise on the heat that is already being produced through wastewater purification.

According to the city, the state of the art circular facility will be able to extract around 6 degrees Celsius of heat out of the water. Then, it can use that heat to generate a temperature of around 90 degrees Celsius and use it to heat the water going into Vienna’s district heating system.

The district heating system – a pipeline into thousands of homes

Currently, the Austrian capital has one of the largest heating systems in Europe. With a length of more than 1,300 kilometres, it services around 420,000 households. The city estimates that it saves around 1.5 million tonnes of CO2 annually.

L-R: City Councilor Peter Hanke, Klaus Gruber, Managing Director of Wien Energie,
Climate Councilor Jürgen Czernohorszky at the groundbreaking ceremony for the heat pump,
Source: City of Vienna 

At the same time, a good 50% of the system is powered by waste heat: from power plants, waste incineration, industrial waste heat and biomass. A small portion of that comes from renewable sources like geothermal and solar thermal. However, Wien Energie, the public company operating the system, says it plans to power all of it with renewables by 2040.

Furthermore, the city has pledged to be climate-neutral by 2040. According to Climate Councillor Jürgen Czernohorszky, this large scale heat pump is already an eco-project due to the fact that it will be powered with renewables.