Image: Project Management J├╝lich on behalf of the BMBF

Wind turbines with integrated electrolyser demonstrate sustainable hydrogen production at sea

The offshore wind turbines of the future will not produce electrons, but molecules. Self-sufficient units consisting of a wind turbine and integrated electrolyser produce green hydrogen on an industrial scale and save the costs of an electrical grid connection. In this way, they can make a significant contribution to the reduction of greenhouse gases. In a second step, the green hydrogen can be converted into other synthetic fuels and energy carriers. This vision is to become reality within the framework of the H2Mare lead project funded by the Federal Ministry of Education and Research (BMBF).

The H2Mare lead project aims to ensure that a completely new type of plant finds its place at sea in the future – a solution that optimally integrates an electrolyser for the direct conversion of electric current into an offshore wind turbine. In addition, further offshore power-to-X processes are being investigated.

For this purpose, the entire value chain is considered: from wind energy generation and hydrogen production to the conversion of hydrogen into methane, liquid hydrocarbons, methanol or ammonia and consumption by industry or the energy sector. This means that various industrial connection utilisation and storage options are possible. A significant cost advantage in the production of large volumes of hydrogen is the goal.

Within four years, H2Mare – consisting of four collaborative projects with a total of 35 partners – aims to lay the foundation for technology leadership and support the achievement of climate targets through accelerated greenhouse gas reduction.

“Together with our partners, we want to establish the production of green hydrogen offshore with H2Mare,” said Christian Bruch, CEO of Siemens Energy AG. “We bring to this our offshore wind and electrification capabilities as well as our electrolysis expertise. H2Mare combines the strengths of research and industry – for the sustainable decarbonisation of the economy and the benefit of the environment. We need policy support to drive innovative solutions for a Green Hydrogen Economy.”

Siemens Energy is responsible for the overall coordination of H2Mare with the support of institutes of the Fraunhofer Gesellschaft.

The four H2Mare projects are being driven forward independently of each other:

OffgridWind: pursues the implementation of a plant concept that realizes electrolysis directly in the offshore wind turbine, aiming at a high efficiency.

H2Wind: includes the development of a PEM electrolysis (PEM = Proton Exchange Membrane) optimally adapted to the offshore environment and to the wind turbine. In addition to the longevity of the turbines and the challenge of seawater treatment, the maximum yield of wind energy is a goal of the project.

PtX wind: In contrast to pure offshore hydrogen production, the focus is on conversion into more easily transportable synthetic energy sources and fuels such as methanol and ammonia. Power-to-X products are generated via high-temperature electrolysis andCO2 extraction from the air or the sea. Direct salt water electrolysis is also being tested.

TransferWind: Transfer of knowledge to the public as well as the exchange of expertise across projects are addressed in TransferWind. Safety and environmental issues as well as infrastructure requirements are also considered.

An important part of the investigations is the integration of individual processes into overall systems: for example, the efficiency of the overall process can be increased by heat integration of high-temperature electrolysis in PtX processes. This also includes the concept for storing and transporting the hydrogen or other power-to-X products by ship and pipeline. The interactions between the various processes and the plant as well as their impact on the environment at the site are investigated, evaluated and further developed for the entire life cycle.

Challenging on the material level is the application of partly existing technology for the first time in offshore environments, respectively the research of new materials and components for offshore use. The development of digital twins for the various plant components and technical and economic analyses based on them is being carried out in all four H2Mare projects.

H2Mare is one of three lead projects of the Federal Ministry of Education and Research. With its largest research initiative to date on the subject of the energy transition, it is supporting Germany’s entry into the hydrogen economy. The three hydrogen lead projects H2Giga, H2Mare and TransHyDE are the result of an ideas competition and form a central contribution of the BMBF to the implementation of the National Hydrogen Strategy.

Over a period of four years they are to remove existing hurdles that impede Germany’s entry into a hydrogen economy. This involves the series production of large-scale water electrolysers (H2Giga), the generation of hydrogen and downstream products at sea (H2Mare) and technologies for the transport of hydrogen (TransHyDE).

More than 240 partners from science and industry are working together in the three hydrogen lead projects. In spring, the projects were launched on the basis of non-binding funding prospects. The total funding will amount to up to 740 million euros.

Fraunhofer IWES is a project partner in the collaborative projects OffgridWind and H2Wind, and an associated partner in TransferWind. Scientists are modelling different scenarios for hydrogen-producing wind farms and carrying out specific tests on heat coupling and seawater treatment.