Decarbonisation of District Heating in Vienna – More Than Just a Plan

The current paper addresses the presentation of the district heating decarbonization strategy. By introducing the implementation project Large-Scale Heat Pump Spittelau, it will detail the efforts toward realizing this strategic goal.

by Holger Huschka, Rusbeh Rezania and Marieluise Pöschko-Reinweber

By 2040, decarbonization is to be achieved, thereby overcoming dependence on oil, gas, and coal for heating. This requires a shift to highly efficient, emission-free district heating or decentralized renewable energy sources. With the program Phasing Out Gas the City of Vienna is driving this transition. This contributes to climate protection and ensures the city’s high quality of life [2].

The current paper addresses the presentation of the district heating decarbonization strategy. By introducing the implementation project Large-Scale Heat Pump Spittelau, it will detail the efforts toward realizing this strategic goal.

The aim of the project was to build a waste heat utilization system at the Spittelau thermal recycling plant. The waste heat from the flue gas and the cooling water system of the existing plant for the thermal utilization of Viennese waste is used as a source for large heat pumps and thus heats the return flow of the Viennese district heating network.

The realization of this project will increase the thermal output of the incineration plant from around 60 MWth to 76 MWth.

The most important advantages are as follows:
• the integration of waste heat from the flue gas into the district heating network,
• the reduction of primary energy for the district heating supply,
• a CO2 reduction of 22,000 tonnes of CO2 per year in heat generation,
• supplying 16,000 households with environmentally friendly district heating,
• increasing the overall efficiency of the thermal waste utilization plant to approximately 95 %,
• reducing the heat supply from the cooling water system into the Danube Canal and
• internal utilization of the condensate produced and thus a reduction in the use of Danube water of up to 125,000 m3/a.

The experience and knowledge gained will be incorporated and taken into account in future large-scale heat pump projects, particularly in the decarbonisation of waste recycling plants in combination with carbon capture technologies.


[2] Stadt Wien (Hrsg.): https://www.wien.gv.at/umwelt/programm-raus-aus-gas

---

published: Abfallwirtschaft und Energie, Band 2, 1|2025
Keywords: Energy Recovery, Pollution Control, Sustainability, Climate, Austria