Daniela Trauninger
December 5, 2025
Vienna plans to decarbonize 200,000 homes with help from underground
This video is part of: Centre for Urban Transformation
Vienna will tap into geothermal energy 3km beneath its streets using ‘formation water’, which is pumped from rock in an underground reservoir to provide carbon-neutral domestic heating. The project will use part of Vienna’s existing district heating network. Which provides heat to more than 460,000 homes through more than 1,300km of pipes.
Vienna is taking a major step towards carbon neutrality by turning to geothermal energy buried deep underground. The city plans to decarbonize heating for up to 200,000 homes using this sustainable resource.
Geothermal energy in Vienna will power a green heating network
The project will extract heat from formation water located 3 km beneath the city. This water, pumped from an underground rock reservoir, will transfer its heat via a heat exchanger before being reintegrated into Vienna’s existing district heating network.
Expanding an already vast heating network
Vienna’s district heating system currently serves over 460,000 homes through more than 1,300 km of pipes. Traditionally powered by gas and waste incineration, the network will now incorporate this virtually unlimited renewable heat source.
A sustainable and circular system
After the heat is extracted, the cooled formation water will be pumped back underground in a sustainable open-loop system, ensuring environmental balance.
The project is led by deeep, a collaboration between OMV and Wien Energie. Their goal is to provide heat to 20,000 homes by 2028, eventually reaching 200,000.
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