Climate-friendly heat supply for Zofingen and Oftringen
StWZ Energie AG and Primeo Energie have founded the company Fernwärme Unteres Wiggertal AG. Together, the two energy service providers want to utilise synergies to build a district heating network. The project is to be realised in two stages and start in 2026.
StWZ Energie AG and Primeo Energie want to jointly create a sustainable district heating supply in the lower Wiggertal valley. To this end, the energy service providers have founded the joint company Fernwärme Unteres Wiggertal AG (FUWI) as of 19 September 2025. The aim is to combine “infrastructure, customer proximity and energy expertise” in order to further develop the heat supply in a climate-friendly way.
The new network is to be operated using waste heat from the erzo-KVA waste incineration plant and from existing decentralised StWZ energy centres. Existing heating networks from StWZ in Zofingen and Primeo Energie in Oftringen are to be integrated.
The first households are to be supplied with low-CO2 heat energy from the new network from summer 2027. Two phases are planned for the expansion. Phase one is to begin in 2026 from the erzo-KVA waste incineration plant and run towards Oftringen Süd and Zofingen. The second phase will follow in 2030 at the earliest and will depend on the planned new construction of the waste incineration plant. This will require the consent of the people of Oftringen for the zoning of a required piece of land. If both construction phases go into operation, 10,000 households could be supplied with heat and 30,000 tonnes of CO2 could be saved.
Michael Schneider, Managing Director of Primeo Wärme AG, sees the energy revolution as a heating revolution. This step lays a “foundation stone for a long-term sustainable heat supply in the lower Wiggertal”. “By combining regional energy sources with modern technology, we are reducing CO2 emissions in a targeted manner and expanding the supply of reliable, decarbonised heat,” Paul Marbach, Managing Director of StWZ Energie AG, is quoted as saying.