The electrolysis system will use power to separate water into hydrogen and oxygen.
The hydrogen can be used to produce methane for storage, which can then be redeployed later for power or heat generation.
Testing is due to begin this month and run until October in a standard container at RWE’s Niederaussem Coal Innovation Centre, as part of the utility’s wider Power-to-Gas initiative.
Niederaussem is the site of a highly-polluting, lignite-fired power station run by RWE.
But a company press spokesman says once operational, the new technology would only use power derived from excess wind generation.
The system is based around a so-called proton exchange membrane (PEM), which separates the areas in which oxygen and hydrogen emerge in an electrolyser.
Germany is looking to find ways to store electric power to be available at times of peak consumption as part of its shift to more renewable generation.
“Renewables often generate more electricity than is consumed when energy demand happens to be low,” says Ulrich Hartmann, RWE board member responsible for research and development.
“At our Coal Innovation Centre, we are investigating various ways of storing and using this excess energy. That is becoming more and more important as renewables go on growing.”
RWE follows other utilities experimenting with electrolysis systems. Swedish utility Vattenfall early last year said it has signed up to a project with German companies Enertrag and Siemens, and French oil firm Total to build an electrolysis unit to generate hydrogen at a biogas and wind plant north of Berlin.