Offshore electrolysis 

As wind turbines are placed further out to sea, hydrogen production close to the source becomes more attractive. After all, the generated energy must also be transported to land. This can be done via heavy electricity cables, but it is cheaper and more efficient to transport hydrogen gas molecules. That is why NortH2 is also looking at possibilities to convert the generated wind power into hydrogen directly at the wind turbines: electrolysis at sea.

Three options

NortH2 wants to produce large volumes of green hydrogen. The consortium is investigating three options for electrolysis: on a platform, on a man-made island, and directly in the wind turbines.

Electrolysis on a platform

One example is the PosHYdon pilot project, an initiative of Nexstep (national platform for reuse and dismantling) and TNO, in collaboration with industry partners. PosHYdon will produce green hydrogen from renewable wind and solar electricity on Neptune Energy’s Q13a oil and gas platform, located about ten kilometres off the coast of The Hague. If the trials are successful, the North Sea will not only be one of the best places for offshore wind (it is relatively shallow and often windy), but also the first location to produce offshore hydrogen. Han Fennema, CEO of Gasunie: ‘If we want to achieve our climate ambitions, we must have a large-scale hydrogen infrastructure in place in time. The PosHYdon pilot project can be an important step in the right direction.’

Electrolysis on an island, following the Danish example

Denmark was the first country to make concrete plans to build an energy island. The Danish government has already taken steps to construct two such islands: one man-made island in the North Sea and one on an existing landmass in the Baltic Sea. The cables from hundreds of wind turbines in the North Sea will soon converge on the man-made floating island. From the hub, green power will be sent to the surrounding countries. In time, green hydrogen will also be produced on the islands.

Electrolysis in the wind turbines

Integrating electrolysis into a wind turbine avoids electrical conversion and transport losses between the wind turbine generator and the electrolyser (on a platform, island, or the mainland). This can increase the efficiency of the electrolysis process. One such project is “Brande Hydrogen” from Siemens Gamesa in Denmark.

In the coming months, NortH2 will work with partners to investigate which option is best for the project. The results of this study are expected in autumn 2021.