Blue oceans and green power

An ambitious € 100 million project is under way to harness the power of the high seas to directly produce green hydrogen and other Power-to-X products such as green methanol and green ammonia. Offshore options have increasingly been emerging as strong contenders for the generation of renewable electricity - and the direct production of green hydrogen from wind energy without grid connection can be significantly cheaper than it otherwise would be on land.

The efforts are supporting one of the three lead projects seen as vital to the implementation of Germany’s national hydrogen strategy over the next four years. They form the largest funding initiative from the Federal Ministry of Research on energy transition, providing a decisive impetus for the country’s entry into the hydrogen economy. Technologies for the generation, transport and use of green hydrogen have potentially huge benefits for the German economy - and the knock-on benefits for key climate-impact areas such as industry, transport and heat supply. These €700 million flagship, or lead projects are the result of a wide-ranging consultation where business leaders and scientists were asked for their visions of a hydrogen future and asked to suggest large-scale industrial projects. Thirty-two ideas were received, from which the three were chosen by an independent panel of experts. Around 200 partners are expected to be involved over the four-year period.

One of them, lead project H2 Mare aims to harness this potential by using renewable electricity directly at sea to produce hydrogen and associated by-products. The rationale? Offshore wind turbines generate significantly more electricity more regularly than their onshore counterparts. While the average nominal output on land is around 3.5 megawatts, it rises to 5 on water.

The 35 partners backing this project aim to create the necessary technologies by integrating a water electrolyser with a wind turbine, not only saving on the infrastructure costs but also by the decoupling of electrolysis and network, also easing the pressure on local network structures. There is another advantage of the offshore option – the potential availability of areas for generating wind energy is significantly more than on land. Of course, the success of this depends to some extent on the continued advancement of other pioneering approaches such as water vapour and seawater electrolysis. Carbon dioxide and nitrogen are vital ingredients for the Power-to-X products derived from the air or seawater. The project is in its early stages and there still issues to be addressed such as those relating to safety, possible environmental impacts along with life cycle analysis and technology.

The four areas of input for DECHEMA

DECHEMA’s H2 Mare involvement includes planning an experimental offshore platform to act as a real-life laboratory to demonstrate PtX-technologies in an offshore environment. It also has key roles in other projects such as the H2Giga, TransHyDE and Trans4Real: several large “sandbox” projects to investigate an integration of renewable electricity and application of hydrogen. The H2Mare project itself comes within four parts: OffgridWind will create all the prerequisites for integrating an electrolyser directly into a wind turbine.

This requires a brand new type of turbine and a different foundation than what is currently used.

OffgridWind is researching both of these - supplemented by storage of the produced hydrogen in the wind turbine and it’s transport to the mainland.

It will also be able to simulate the operation and calculate the costs over the entire life cycle of the wind turbines for hydrogen production at sea. This makes it possible to determine the conditions under which systems - such as the one developed in H2 Mare - can be operated profitably. H2 Wind will be responsible for the electrolyser, something innovative, compact and able to work efficiently and quasi-self-sufficiently, despite the rough conditions. To this end, the project will develop processes for not only treating and supplying water for electrolysis, but also for storing the hydrogen.

PtX-Wind is specifically concerned with the generation of further Power-to-X products and the way that elements, such as CO2 and nitrogen, are obtained on-site from the air or the sea. Its additional focus on water vapour electrolysis and seawater electrolysis is equally important - if seawater electrolysis is successful, seawater will not need to be desalinated before the electrolysis.

A fourth element called TransferWind, is intended to answer overarching questions that are most likely to affect all the projects; be they security and environmental issues or infrastructure requirements. The Principal Engineer, Steffen Schirrmeister of Thyssenkrupp, the engineering partner in the PtX-Wind element, agreed that while the potential is great, there are questions to be answered and variables to be considered, such as the type and availability of materials such as special grades of stainless steel or titanium.

“If you go offshore, you have to deal with atmosphere, for example. As for the platform - is it a ship or is it a stable platform? Is it only the water eloctrolysis offshore and the conversion plant onshore? There’s also the question of available resources,” he said. “Because you have to move them to the platform. Then there’s a question of the logistics.

What is easier to transport - the electricity or the chemicals?”

| Original version published in ACHEMA Inspire, June 2021. |