(Cuxhaven) – Scientists have investigated how hydrogen produced from offshore wind energy in an off-grid system can contribute to meeting future demand and diversifying the hydrogen supply. The group from industry and research has now presented the final report.
“OffsH2ore – offshore hydrogen production using offshore wind energy as an isolated solution”
The starting point of the “OffsH2ore” project is a fictitious wind farm in the North Sea, which is directly connected to a 500 megawatt electrolysis platform. This can produce up to 50.000 tons of green hydrogen per year. The system is based on a scalable and modular structure that can be easily adapted to different hydrogen production capacities, the paper says. The fresh water for PEM electrolysis is provided by desalination of seawater and the waste heat from electrolysis is used. The hydrogen produced is cleaned and dried, compressed to 500 bar and loaded onto a transport ship that delivers up to 400 tons of hydrogen per trip from the offshore platform to land. So much for the model.
Diverse research tasks
This resulted in a variety of tasks that needed to be investigated. The consortium has dealt in particular with issues relating to the storage, transport and logistics of hydrogen, the operation and maintenance of offshore systems and regulatory aspects. In addition, technical solutions had to be developed for a maritime hydrogen supply chain based on the ship transport of compressed gaseous hydrogen. According to the information, this included the development of a hydrogen loading system, the design of a transport ship and the development of a logistics concept from the offshore location to the unloading port.
Scientists at Fraunhofer ISE have designed an electrolysis system as part of the OffsH2ore project. © Fraunhofer ISE
The project differed from other concepts and research approaches in particular in that it “focused on the storage and transport of hydrogen in compressed gaseous form”. Although the team developed the logistics concept specifically for an offshore platform, according to the experts, the proposed transport solution is in principle also suitable for long-distance transport of hydrogen by ship (“port-to-port”).
Hydrogen has never been produced at sea
The project partners describe the “biggest challenge” as the fact that green hydrogen has not yet been produced at sea. “Therefore, the focus of the concept was on the interfaces between the individual components, on the ancillary systems required for operation, on questions about maintenance and general approval requirements.” The research team’s most important findings:
- An offshore hydrogen supply chain based on compressed gaseous hydrogen is technically feasible.
- The preferred technology should be “Proton Exchange Membrane” (PEM) electrolysis due to the high power density and high hydrogen pressure.
- The transport ship can be used as a floating storage facility.
- Pressure accumulators based on carbon fiber composite materials are best suited for storing hydrogen at a pressure of 500 bar.
- Due to synergies regarding the use of waste heat from electrolysis, the multi-effect distillation (MED) process should be used for water desalination.
- For some technical components, there is a need for further development in adapting to high-pressure hydrogen as well as the need to scale up production capacities. The biggest technical development challenge is the ship's loading and unloading system.
- Overall, hydrogen production costs of six to seven euros per kilogram (Levelised Costs of Hydrogen, LCoH) appear to be feasible until delivery to the edge of the port.
There is a need for further research into standards: According to the report, there are currently no applicable regulations for the offshore production and transport of hydrogen by ship. In order to be able to implement the solutions developed in practice in the future, the research team recommends that political decision-makers create the legal framework as well as appropriate regulatory and financial incentives for a lighthouse project in Germany or Europe.
To this end, standards and regulations for the production, storage, transfer and transport of hydrogen at sea, including certification requirements, would have to be developed. In addition, there is the designation of areas for offshore hydrogen production and the provision of hydrogen infrastructure on land.
Conclusion: With offshore hydrogen production, “offshore locations that are too far from the shore for a grid connection could also be developed in the future.” Compared to hydrogen imports, offshore hydrogen production with high full-load hours offers “the opportunity to represent the entire value chain at a national level.” According to the researchers, “offshore hydrogen production has a high potential to make a significant contribution to achieving the ambitious goals of the energy transition.”
PNE AG was involved as project coordinator in the “OffsH2ore” joint project, as were the Fraunhofer Institute for Solar Energy Systems ISE, Silica Process Technology GmbH, Kongstein GmbH and Wystrach GmbH. The project was supported by the Federal Ministry for Economic Affairs and Climate Protection as part of the “Applied Non-Nuclear Research Funding”.
The final report “Project OffsH2ore – offshore hydrogen production using offshore wind energy as an isolated solution” is available free of charge PDF (102 pages).
Photos
Schematic representation: The water for electrolysis is obtained via a seawater desalination plant. The compressed hydrogen is transported to land by ship. On the land side, the unloading of the ship in a port is taken into account. The landside infrastructure from the edge of the harbor such as storage and further transport of hydrogen were not part of the project. © Project report, Fraunhofer ISE
