Kick-off for green hydrogen from Mainz

Joint energy storage project involving the utility company Stadtwerke Mainz, Linde, Siemens and RheinMain University is officially commissioned

Mainz, Germany. After just over a year of construction work, a beacon project of Germany’s switch to renewable energy has been commissioned at a ceremony attended by the First Minister of Rhineland-Palatinate Malu Dreyer and the Mayor of Mainz Michael Ebling. By pressing a symbolic button, hydrogen production was officially launched at the Energiepark Mainz by the Chairman of the Board of Linde Group, Dr. Wolfgang Büchele, Siemens board member Prof. Siegfried Russwurm, two board members of Stadtwerke Mainz AG, Detlev Höhne and Dr. Tobias Brosze, as well as Prof. Dr. Detlev Reymann, the President of RheinMain University. Jointly developed by the project partners, the plant will produce hydrogen using green electricity, some of which is produced by local wind turbines. What makes Energiepark Mainz special is its size: As the world’s second biggest plant of its type, the research project has entailed investment of around17 million Euro and is co-financed by the German Federal Ministry for Economic Affairs and Energy as part of its “Funding Initiative for Energy Storage”.

Already today, wind turbines and photovoltaic plants have to be switched off at certain times due to lack of adequate grid capacity. This problem will become even more acute with the further expansion of renewable energy over the coming years. This “surplus” electrical energy can be stored at Energiepark Mainz by breaking down water into hydrogen and oxygen using clean technologies and then converting it back again for use as required. This makes for greater flexibility in the use of renewables, as they will be available whenever they are needed.

The Energiepark’s hydrogen electrolysis system Silyzer was provided by Siemens. What sets the Mainz facility apart from other far smaller pilot projects is that it involves a highly dynamic PEM pressure electrolyzer which, with an input current of up to 6 megawatts, is the biggest of its kind anywhere in the world. The PEM electrolyzers are suitable for high current densities and are capable of responding to the wide fluctuations in power production from wind and solar power plants within just milliseconds. In the electrolyzer, a proton-exchange membrane (PEM) splits the areas in which oxygen and hydrogen are created. This means that the Energiepark is able to work on a sufficiently large scale to prevent bottlenecks in the power grid and to stabilize the power supply drawn from smaller wind farms.

“The power systems of the future will be much more complex, integrated and flexible than they are today. The PEM electrolyzer is an important component for getting this energy puzzle right", stated Professor Siegfried Russwurm at the commissioning ceremony. "Hydrogen electrolysis allows for greater efficiency in feeding renewable energy into the power grid. A temporary power surplus can be captured and stored for future use. Here at the Energiepark Mainz, we have created an innovative system for doing that - laying the foundations for making what was once a vision become industrially viable reality.”