As part of the "OffsH2ore" project, a research consortium from industry and science investigated the feasibility of offshore hydrogen production using offshore wind energy in an island system. The final report is now available.
The "OffsH2ore" project designed a hypothetical North Sea wind farm connected to a 500 MW electrolysis platform. This platform can produce up to 50,000 tons of green hydrogen per year and is based on a scalable, modular design. The electrolysis uses seawater obtained through desalination and the waste heat from the process. In the scenario, the hydrogen produced is purified, dried, compressed to 500 bar and loaded onto a transport ship that transports up to 400 tons of hydrogen per trip to land.
The project focused on various areas of research, including hydrogen storage, transportation and logistics; operation and maintenance of the offshore facilities; and regulatory aspects. The logistics concept of the project, in particular the transportation of compressed gaseous hydrogen by ship, offers potential for long-distance transport of H2.
Offshore production of hydrogen: a novelty
According to the authors of the study, one of the biggest challenges was that green hydrogen had not previously been produced at sea. The most important findings of the project at a glance:
- The offshore hydrogen supply chain with compressed gaseous hydrogen is technically feasible.
- Proton Exchange Membrane (PEM) electrolysis was identified as the preferred technology due to its high power density and high hydrogen pressure.
- A transport ship can serve as a floating hydrogen storage unit.
- Carbon fiber composite pressure vessels are best suited for hydrogen storage at 500 bar.
- Multi-effect distillation (MED) was recommended for water desalination due to the waste heat utilization of electrolysis.
- Further development work is required, particularly on high-pressure hydrogen systems and the loading and unloading technology of the transport vessel.
- The hydrogen production costs of 6-7 € per kg to the port edge are feasible.
Desideratum: Standardization and regulation
There is a need for further research into the development of standards and regulations for offshore production and the transportation of hydrogen by ship. The research team recommends that political decision-makers create the legal framework as well as regulatory and financial incentives for lighthouse projects in Germany and Europe. Initial approaches are already in place, for example in the AquaVentus project.
Overall, offshore hydrogen production offers the opportunity to develop offshore locations that are difficult to access and to map the entire hydrogen value chain at a national level. This could contribute to achieving Germany's ambitious energy transition targets.
The "OffsH2ore" joint project was coordinated by PNE AG and involved the Fraunhofer Institute for Solar Energy Systems ISE, Silica Verfahrenstechnik GmbH, Kongstein GmbH and Wystrach GmbH. The BMWK supported the research as part of the "Applied non-nuclear research funding".
