Divisions

District heating

Primary and secondary networks

The district heating network of Wien Energie is divided into mains, primary and secondary networks. It is possible to walk along some sections of these networks, meaning that, for example, you can cross the Danube by walking in the pipes under the riverbed. In total, the network of pipes extends over 1,092 km, connecting every one of Vienna’s districts both above and underground.

Across Europe, Wien Energie is one of just a handful of energy companies that have divided their network into primary and secondary networks. The primary network acts like a highway for transporting heat, large quantities of which are transported through it at high temperatures and pressure throughout Vienna.

This heat is then fed into the secondary network at so-called transfer stations, from which it is then transported to customers’ building and heating systems.

The interplay of large and smaller networks offers a considerable advantage in that larger quantities of heat can be transported across Vienna in a much swifter manner, while faults can be dealt with quickly and service disruptions largely avoided.

The network system is a closed circuit comprised of supply pipes, in which hot water flows from the heat generator to the customer, and of return pipes, in which the cooled water flows back to the heat generator.

A total of 76,500 cubic metres of water is transported along a 533-km long primary network at a maximum pressure of 23.5 or 28.5 bar and at a temperature of a maximum of 160° C. Along a 560-km long secondary network, a total of 15,800 cubic metres is transported at a maximum pressure of 6 or 10 bar and at a temperature of a maximum of 90° C.

Pipeline to the north-west of the city: construction work starts in summer 2008

The main district heating pipeline to the north-west of the city has been in operation since May 2007. Having completed a pan-European tendering process, construction work began in summer 2008 on Section 2, which links the Spittelau waste incineration plant with Floridsdorf, Vienna’s 21st District, by means of a connecting pipeline.

Since the end of August 2007, another main district heating pipeline has connected the Pfaffenau waste incineration plant, opened on 20 September 2008, with the existing mains network at the Simmering power station.

The plan is to connect the southwest of Vienna with the districts situated further to the north. The so-called Danube district heating pipeline will make it possible to transport heat from the Simmering, Donaustadt, Simmeringer Haide and Pfaffenau production facilities, as well as the heat storage tanks in Kagran and Arsenal, to the northern districts of the city. A feasibility study has been commissioned to determine an efficient and cost-effective route.