A consortium of several research institutes in Kiel has developed a process for electrolysis from saltwater at offshore wind turbines. What makes this technology special is that microorganisms are to replace expensive catalysts and convert seawater directly into hydrogen. The process is now to be tested for three years by the GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel University of Applied Sciences and the technology company Element22.
The SalYsAse project aims to break new ground in electrolysis. Conventional electrolysers require treated and desalinated fresh water to prevent corrosion and the formation of toxic chlorine gas. However, the direct use of seawater could make costly desalination processes unnecessary.
This, however, brings new challenges, such as the high corrosiveness of salt water, which can damage the sensitive components of an electrolyser. The Kiel research team aims to solve the difficulties of salt water electrolysis by using suitable materials in combination with specially adapted microorganisms.
‘The chemical element iridium is often used as a catalyst because it is highly resistant to corrosion. However, it is rare and therefore only available in limited quantities. That is why we want to use biocatalysts in the form of microbes,’ said project leader Prof. Dr. Mirjam Perner, according to the GEOMAR press release.
Microbes replace rare iridium
The bacteria are to be settled on porous titanium structures, which also act as a transport layer for electricity and reaction media. ‘The special feature of SalYsAse is that the porous transport layer not only conducts electricity and reaction media. We design it so that this layer also acts as a carrier for the microbes,’ says Florian Gerdts, senior process engineer at Element22.
The process is to be used directly at offshore wind farms, thereby avoiding electricity transmission losses. Offshore wind farms often produce more energy than can be transmitted to land via submarine cables. Direct conversion to hydrogen on site could make this surplus energy usable.
The project is linked to the Schleswig-Holstein innovation alliance CAPTN Energy, which specialises in renewable energies for maritime applications. The researchers are receiving 733,000 euros in funding from the Federal Ministry of Research, Technology and Space.
In 2023, an international team of researchers investigated a similar process. However, the scientists from the universities of Adelaide, Tianjin, Nankai and Kent State University did not rely on microbes, but on a special protective layer for the electrodes made of Lewis acid.
