5.2 Miesbachgasse anergy network (Sozialbau)
The "Miesbachgasse anergy network" project by the WOHNBAU housing cooperative (part of the SOZIALBAU housing association group) demonstrates how heating systems in existing buildings can be decarbonised. The heating system in the flats dating from the 1960s was first converted from separate gas boilers to gas central heating, which was then successively replaced with a renewables-based supply. An air-to-water heat pump, solar panels and a buffer tank now supply the residential building with fossil-free energy.
However, the project is actually the starting point of a much larger vision: the development of a communal anergy network serving several properties and incorporating renewable energy sources such as groundwater or geothermal probes. This would not only replace fossil fuels, but also allow cooling of the buildings in the summer months.
Retrofitting of such a network in an existing built-up area is a technical as well as a legal challenge, though it does have a high level of scalability. Thanks to minimally invasive techniques – e.g. installing piping in disused chimney flues – the measures are cost-effective, socially responsible and accepted by tenants. As a showcase for Vienna's transition to clean energy, the Miesbachgasse project demonstrates how existing buildings in built-up urban areas can be retrofitted for a climate-neutral future.
Takeaways & challenges
- Existing buildings can be decarbonised – and it can be done using minimally invasive techniques.
- Centralised, system-based solutions allow flexibility: further renewable technologies – e.g. brine/water heat pumps – can be integrated at any time.
- Legal and organisational frameworks – esp. questions regarding billing of heating costs, ownership structures and how neighbouring properties are financed – are key obstacles in the development of an anergy network.
- The investment and installation costs of anergy networks need to be apportionable to tenants. However, according to an Austrian Supreme Court ruling (2022), the heating provider and the property owner may not be one and the same; a heating price can only be charged in the case of collective systems supplying multiple properties – otherwise only the operating costs.
- The project highlights the importance of a professional "heating network management" team with a combination of technical, economic and legal expertise. A successful roll-out requires stamina and skilful negotiation, as well as powerful, convincing arguments.
- The extensive preparation, moderation and planning work required must be done by an external coordinator and carried out in a financially viable manner.
- Funding schemes and political pressure to deliver are vitally important in order to actually get projects done; even with committed "facilitators" in place, the success rate to date remains low.
This project was supported with funding from the "Grätzlförderung" scheme.
Project partners
- WOHNBAU housing cooperative (part of the SOZIALBAU housing association group)
Find out more here: https://www.wien.gv.at/umwelt/vorzeigeprojekt-miesbachgasse (German)