Fraunhofer ISE researchers have optimized the technical concept for a hydrogen plant located at sea. They claim their design is “technically and economically viable.”
The power source for electrolysis comes from an offshore wind farm, which is connected directly to the 500 MW electrolysis platform. The platform can produce up to 50,000 tons of green hydrogen per year. Fresh water for the PEM electrolyzer is obtained by removing salt from seawater with the residual heat of electrolysis.
The produced hydrogen is cleaned and dried, compressed to 500 bar and transferred to a transport vessel that can transport up to 400 tons of hydrogen from the pier to the mainland. This concept is independent of the hydrogen transfer pipe and offers flexibility in the choice of location.
“The results show that the production of hydrogen directly in the sea using a PEM electrolyzer is technically and economically feasible,” the researchers explained.
The project was financed by the German Federal Ministry for Economic Affairs and Climate Protection.
“With the concept presented by the consortium, rapid and large-scale implementation is realistic,” the researchers said.
The concept guarantees hydrogen production without regional competition.
“Offshore hydrogen production offers the opportunity to cover the entire value chain at the national level and at the same time decouple offshore wind energy and grid expansion,” said project coordinator Marius Holst.
In order to find out the costs of hydrogen production, the cost-optimal capacity of the offshore wind farm was initially determined based on the electrolysis power of 500 MW. The cost of the minimum production of hydrogen is due to the 602 MW of wind power. In this case, they are 5.92 euros/kg with just under 5,000 full charge hours by electrolysis.
Hydrogen production costs increase and full charging hours decrease as wind power decreases. For example, the hydrogen production costs of a 490 MW wind farm are €6.37 (€7.04)/kg and full load hours are approximately 4,225 h/a. As a result of the lower wind capacity, the 500 MW electrolysis is significantly oversized and can no longer operate at rated load.
The consortium working on the project was Fraunhofer ISE, PNE AG as project coordinator, SILICA Verfahrenstechnik GmbH, KONGSTEIN GmbH and Wystrach GmbH.
Researchers at the University of Adelaide in Australia recently discovered a way to produce hydrogen directly from untreated seawater. To do this, they added an acid layer on top of the catalysts in situ.