With a symbolic push of the facility’s start button, the world’s largest green hydrogen plant was inaugurated in Mainz today.

Thereby a lighthouse project in Germany’s journey towards renewable energies was officially kicked off after a construction period of almost one year.

Malu Dreyer, Minister-president of the state of Rhineland-Palatinate, Eveline Lemke, Minister of Energy and Michael Ebling, Mayor of the City of Mainz, were present at the official opening ceremony. The CEO of The Linde Group, Dr. Wolfgang Büchele, together with Siemens board member Prof. Siegfried Russwurm, members of the board of Stadtwerke Mainz AG, Detlev Höhne and Dr. Tobias Brosze, and Prof. Detlev Reymann, President of the RheinMain University of Applied Sciences, were on hand to officially start operations at Energiepark Mainz.

The energy park is the result of a JV between these partners and has been designed to produce hydrogen using electricity from environmentally sound sources of energy such as neighbouring wind parks.

Around €17m has been channeled into the project, which is also being funded by Germany’s Federal Ministry for Economic Affairs and Energy within the framework of its “Förderinitiative Energiespeicher” (Energy Storage Funding) initiative.

At the festive ceremony, the partner figureheads and guests from Germany’s national, state and local political circles all agreed that the energy park and its underlying technical concept could become a key milestone in Germany’s transition to renewable energies.

Already today, wind and solar power stations have to be switched off at certain times if they produce too much energy for the grid. This problem is set to increase over the coming years as the renewable energy network expands.

Energiepark Mainz can use this ‘surplus’ electricity to break water down into oxygen and hydrogen.

The resulting environmentally sound hydrogen can be stored and then used at a later date when demand is higher. This process will enable renewable energies to be harnessed more flexibly to dynamically meet fluctuations in demand.

“Fuel-cell drive technology has advanced greatly and is now being launched to the market,” explains Büchele.

“If this technology is adopted on a wide enough scale, it has the potential to significantly reduce traffic-related environmental pollution. Today, most of the hydrogen that Linde supplies to filling stations is already ‘green’. Energiepark Mainz has the capacity to produce enough hydrogen for around 2,000 fuel-cell cars.”

In the project, Linde is responsible for purifying, compressing, storing and distributing the hydrogen. The company’s innovative ionic compressor technology ensures that the compression process is extremely energy efficient, giving the plant a high degree of operational flexibility.

The hydrogen produced in Mainz-Hechtsheim will be stored on site and partly loaded into tankers to supply hydrogen fuelling stations. Some of the hydrogen will also be fed into the natural gas grid for heating or power generation.

Siemens delivered the park’s hydrogen electrolysis system. This highly dynamic, PEM-based high-pressure electrolysis system is a technological highlight of the Mainz plant, clearly setting it apart from other, significantly smaller pilot projects. With a peak performance of six megawatts, it is the largest system of this kind in the world. The energy park therefore has enough capacity to prevent bottlenecks in the local distribution grid and to stabilise the power supply of smaller wind parks.