Zittau pilot plant uses waste heat from electrolysis

12.09.2025

Source: E & M powernews

The hydrogen flagship project "H2Giga" has gained another building block. A pilot plant that combines electrolysis, a heat pump and a heating network has gone into operation in Zittau.

Heat extraction from the electrolysis process is now being put under the microscope in a test plant that has gone into operation on the premises of Stadtwerke Zittau. The Fraunhofer Institute for Energy Infrastructures and Geotechnologies (IEG) and its partners have christened the complex the "Laboratory Plant for Sector-Coupled Utilization of PEM Electrolysis Products" (LA-SeVe).

In addition to a PEM electrolyzer, components of the plant include a heat pump, which is intended to make the waste heat from the electrolysis process usable for the district heating network of the Saxon city. The oxygen that is also produced in the process could also be sold later on, according to a statement from the Fraunhofer IEG.

The project partners are initially testing the processes in order to verify their own concepts for industrial sector coupling. They expect to find out how efficiently the electrolyser and heat pump work together in electricity-, heat- or hydrogen-driven operation. The operation and parameters depend on whether the focus is on using green surplus electricity, saving fossil fuels or optimizing hydrogen production.

Testing industry-related processes

The participants themselves are setting the bar high for the project. They want to "prove that the extraction and effective use of the electrolysis product heat improves the economic efficiency of electrolysis," says Thomas Emmert, Head of the Research and Development Department at Linde GmbH. Linde is the overall project coordinator of the "IntegrH2ate" project, as part of which the plant was developed and whose other consortium partner is the Fraunhofer IEG with its Zittau site.

"IntegrH2ate" is in turn part of the "H2Giga" hydrogen lead project, which has set itself the goal of serial production of electrolysers. The Federal Ministry of Research, Technology and Space (BMFTR) has provided around 19 million euros for the Zittau concept. Department head Dorothee Bär (CSU) attended the commissioning ceremony and praised the project as a "building block of structural change" in Upper Lusatia.

Clemens Schneider, project manager at the Fraunhofer IEG, sees the benefits of the test infrastructure in being able to test and qualify industry-related processes for manufacturers and operators. These include the methanation of carbon dioxide, closed carbon cycles, tests of compressors for oxygen and hydrogen as well as hydrogen burners and other components for the use of the main and by-products from PEM electrolysis.

PEM stands for polymer electrolyte membranes, also known as proton exchange membranes. They separate the two electrodes during electrolysis and allow products to pass through.
The project partners needed 2.7 million euros from the investment pot to build the laboratory facility. The electrolyzer is housed in a container that is twelve meters long and 2.5 meters wide. A new transformer station supplies the necessary electricity.

The heat pump, in turn, has a thermal output of up to 105 kW. With the attached buffer tank, the pumps and the control technology, the equipment occupies a five square meter area in an existing hall. The heat pump is connected to the electrolyser via a water circuit.

Author: Volker Stephan