Lighthouse project takes shape

Almost three years ago, engineers at Stadtwerke Gießen (SWG) began the initial planning for the iKWK PowerLahn project. This is an innovative combined heat and power plant with which SWG is taking another major step towards the decarbonisation of district heating in Giessen. The building in which the centrepiece of the three-component system will operate in future has now been largely completed: From mid-2026, three large heat pumps in the energy centre in Schlachthofstraße will extract CO2-neutral heat energy from the water of the passing Lahn river, which will then be fed into Giessen's district heating network.
SWG hosted an event at the construction site of the energy centre to inform political decision-makers and numerous stakeholders about the background and status of the construction work. "With PowerLahn, SWG is taking the district heating supply in our city to a new level," said Lord Mayor Frank-Tilo Becher in his welcoming address, praising SWG's commitment. From June next year, the three heat pumps in Schlachthofstrasse will actually produce enough heat for around 3,900 flats.
In his speech, Alexander Wright, Chairman of the Supervisory Board of SWG, emphasised the innovative strength of Stadtwerke Gießen: "SWG is once again proving that it is able to integrate new technologies into its existing system in a sensible and economical way."

Lots of new things
The three river water heat pumps belonging to PowerLahn are the first to go into operation in Hesse. As a result, there was no experience with the necessary authorisations. Thanks to the meticulous planning of the SWG project team, however, everything went according to plan. "We knew right from the start that we were moving into new territory. But we were always sure that we could manage a project like this," said Matthias Funk, Technical Director of SWG, looking back. In his presentation, he explained the function and numerous advantages of the iKWK system, which includes two combined heat and power plants and an electric heat generator in addition to the heat pumps.

Keyword meticulous planning. The construction work is also right on schedule thanks to the meticulous preparatory work. Specialist companies are currently installing the process technology on the ground floor of the energy centre - i.e. all the pipes, pumps and fittings required for operation. The installation of the three heat pumps is scheduled for the end of July. A lot has already been done in the outside area too: the inlet structure, through which the Lahn water flows to the heat pumps, is already completely finished and blends inconspicuously into the banks of the Lahn. SWG are still working a little longer on the outlet structure. The necessary pipework between the energy centre and the Lahn has already been laid. The completion of the so-called scour, a near-natural area with gravel and large stones where the water is enriched with oxygen on its way back into the river, is scheduled for next year.

An important step for Giessen
The PowerLahn project is taking the heat transition in Giessen a decisive step further. "We are doing everything in our power to support the city in achieving its ambitious climate target," explains Andreas Hergaß, Commercial Director of SWG. The environmental benefits expected thanks to PowerLahn can be summarised in concrete figures: Overall, the iKWK plant reduces carbon dioxide emissions by around 10,000 tonnes per year - compared to the gas boilers and gas turbines that are usually used. It also reduces dependence on fossil fuels. "An aspect that is likely to become increasingly important in view of the rapidly changing geopolitical order," says Andreas Hergaß.