From the sea to the tank - Green hydrogen in the maritime industry

What role will the maritime sector play in the future hydrogen economy? And what trends are emerging in the areas of maritime hydrogen production and application?  
If hydrogen is produced offshore, ports will continue to provide the infrastructure for the logistics of the production technology, which includes electrolysers and classic components of offshore wind energy. In addition, ports are suitable as hydrogen hubs because of their good transport connections and, in the case of imports, as the location of appropriate terminals for storing and distributing the energy carrier and its power-to-X downstream products.1 In the case of imports over distances of several thousand kilometers, shipping will act as the central transport medium, as it has in the past for fossil energy carriers. It is also an important area of hydrogen application. Cargo and passenger ships can only be defossilized via the use of green hydrogen or synthetic fuels such as methanol, ammonia, E-LNG or E-Diesel. Battery propulsion systems alone are unsuitable for this purpose due to their heavy weight combined with short range.2 In short, ports and ships are relevant along the entire hydrogen value chain.  

Hydrogen production in the North Sea

If we look at domestic hydrogen production, the European North Sea region comes into focus. Wide expanses of land, consistently high wind speeds and the virtually unlimited availability of water make the North Sea attractive for offshore electrolysis. The German government's coalition agreement also explicitly emphasizes the central role of offshore wind energy in achieving the electrolysis targets of 10 gigawatts by 2030.3 A number of project developers intend to test electrolysis from offshore wind energy in the North Sea over the next few years. These range from pilot projects in which electrolysers are coupled directly to individual offshore wind turbines to large-scale artificial energy islands in the gigawatt range.4  

In addition to technical and economic considerations, however, it has not yet been decided politically whether the targeted electrolysis capacities should be installed mainly offshore or onshore, in which case the electrolysis would take place onshore and only obtain the required electricity from offshore wind farms via cable connections. In the first case, far more generation potential could be leveraged than by onshore electrolysis coupled to offshore wind farms. This is because cable connections are very cost-intensive and require long approval times. Therefore, the concept of offshore seaward hydrogen production is the most promising for achieving the electrolysis goals here. The most economical transport option for the hydrogen here is by pipeline, since molecular transport can encompass the energetic capacity of several high-voltage submarine cables.5 Pipelines can also serve as buffer storage at the same time. Transport by ship only pays off for distances of several thousand kilometers and is therefore not an option for the North Sea.6 On land, the hydrogen could be fed into the gas grid and distributed from the 2030s onward (before this, the grid must be converted and expanded). This is the concept that the AquaVentus initiative wants to implement. It plans to install 10 gigawatts of electrolysis capacity from offshore wind energy in the German North Sea by 2035 and transport the hydrogen produced to land via a pipeline.  

Hydrogen derivatives can also be produced on the high seas with the help of offshore wind energy. The offshore production of green ammonia and methanol is being tested, among others, by the H2Mare hydrogen lead project funded by the German Federal Ministry of Education and Research. The project has yet to discuss the transportation question of whether the PtX products will come ashore via ships or pipeline.

Hydrogen and derivatives in shipping

As described, shipping will also be an important consumer of hydrogen and its derivatives. The European hydrogen strategy envisages their increasing use for shipping from 2030.7 The question of which fuels in combination with which technology - internal combustion engine or fuel cell - will replace heavy oils and marine diesel cannot yet be answered. On the one hand, some solutions are technically more suitable than others, depending on the area of travel, type of ship, and travel profile. On the other hand, the technologies are still being developed and are only being tested in pilot projects. For example, methanol is already being used in combustion engines and tested in fuel cells on a wide variety of ship types - from push boats to container ships. Demonstration projects with propulsion systems based on ammonia, on the other hand, will start in the near future.8 Hydrogen in pressurized form is already in commercialized use on small private and work boats, whereas the use of liquid hydrogen is not very widespread, apart from individual demonstration projects.9 Which technology ultimately prevails will also depend on its economic viability.

To ensure that the best solutions come to fruition in the field of green hydrogen, we at cruh21, as a consulting company, are focusing above all on networking the respective players and bringing them into an exchange.  

Jimmie Langham is managing director of the consulting firm cruh21. The company advises clients on green hydrogen and sector coupling. Previously, he was managing director of the AquaVentus funding association. Currently, he is one of the three overall coordinators in the flagship project TransHyDE, funded by the German Federal Ministry of Education and Research (BMBF). cruh21 is also active as a networking partner in the hydrogen lead project H2Mare. The company was recently awarded the "Innovation through Research" seal on behalf of the BMBF for its research and development activities.

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