RWE Power is testing new electrolysis technology from Siemens in order to store excess wind power.
The new system, which is currently being built at the Coal Innovation Centre in Niederaussem, Germany, comes with a proton exchange membrane (PEM) and enables electric power to be converted into hydrogen. The electrolysis system is located in a standard container and, after commissioning, is due to be tested from January to October of this year.
Building and testing the system are part of the CO2RRECT research project supported by the German Ministry of Economics and Technology. In addition to numerous research facilities, participants in the initiative include industrial partners like Bayer Technology Services, Bayer Material Science and Siemens.
For the project, experts are jointly examining how hydrogen can be produced from excess renewables-based electricity and carbon dioxide (CO2) utilized as a raw material.
The hydrogen produced by the electrolysis system can be deployed in various ways. Some of it can be used with CO2 from the power plant's flue gas to produce methane in the adjacent new catalyst test facility. As chemical energy in the form of natural gas, it can be placed in interim storage, and when required, the gas can be turned into electricity or made available to the heating market. Alternatively, the hydrogen can be used to make further chemical products, like methanol.
RWE Power's engineers are also examining how fluctuations in renewable energy sources can be offset by storing electricity. One part of the research focuses on investigating the effect of frequent load changes on the functioning of the electrolysis system and on the hydrogen quality obtained.
This is how the conversion of electric energy into hydrogen works: At the core of the new electrolysis technology is a PEM. In the electrolyser, this proton-permeable membrane separates the areas in which oxygen and hydrogen emerge. Fitted at the front and back of the membrane are precious-metal electrodes, which are connected to the positive and negative poles of the voltage source. The water is split at the electrodes.
Thanks to this membrane technology, PEM electrolysis can respond to the fluctuating electricity supply from renewable sources within milliseconds, RWE Power says, adding that such fast response times are achieved by combining the PEM's properties with innovative industrial control technology.