North Sea green H2 production is deemed technically feasible, RWE Offshore Hydrogen director says

Offshore hydrogen production is deemed technically feasible in principle, but requires dedicated efforts of demonstration, testing and industrialisation before commercial deployment, according to RWE's Martin Doernhoefer.

“We believe offshore hydrogen production is in principle technically feasible, but requires dedicated efforts of demonstration, testing and industrialisation before commercial deployment. So the timeline for realising a gigawatt-scale project remains uncertain,” said Doernhoefer, Senior Vice President of Floating, Hydrogen & Development Optimisation at RWE Offshore Wind and Member of the AquaVentus Board of Directors.

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RWE is one of more than 100 companies, research institutions and organisations united under the umbrella of Aquaventus, an offshore wind-to-hydrogen initiative that aims to pave the way for the deployment of 10 GW of electrolysers in the North Sea.

The electrolysis technology is well-established and mature, but its large-scale deployment offshore remains untested which requires a specific approach. As a result, Aquaventus identifies three essential steps to scale up the technology and enable gigawatt-scale hydrogen production at sea.

The first step, AquaPrimus, would be the construction of a demonstration plant to test the development of an integrated system for hydrogen production offshore -- from development, to construction, to commissioning and operation. This will help test components, further develop the technology and lay the foundation for investments in large-scale facilities and the industrialisation of the technology.

The second stage, called AquaSector, would be the deployment of an offshore wind park of between 300 MW and 500 MW with hydrogen production which will enable the further optimisation of operation. This would take three to five years after the demonstration plant.

The third stage, which envisages gigawatt-scale hydrogen production in the North Sea, would take about 10 years to achieve after the pilot plant.

WHY PRODUCE HYDROGEN AT SEA

Producing hydrogen at sea offers a number of advantages. A study conducted by AFRY in cooperation with Aquaventus indicates that hydrogen can be produced from offshore wind in the German North Sea on a large scale and transported by pipeline at about 15% lower cost compared to producing it onshore and transporting it via cables in the form of electricity.

The cost advantages primarily come from transportation. While the installation of electrolysers at sea is more capital-intensive, the higher capex is more than offset by lower transportation costs as pipeline-based hydrogen transport scales much better than cable use which is associated with much higher costs.

In addition, a recent study from e-bridge shows that the yield of renewable wind energy in far-out areas of the North Sea can be optimised with integrated energy transportation networks which use a combination of hydrogen pipeline and electrical cables. These so-called “mixed connection concepts” for energy from the North Sea can reduce costs for society by more than EUR 30 billion.

Once the technology is mature and can be scaled, the process could be significantly faster—by several years—due to the synergies of using a pipeline and avoiding the lead times associated with HVDC cable installation.