Hydrogen production and storage
Currently, most of the world’s hydrogen is produced using fossil fuels. Obviously, this is not desirable for long-term global hydrogen usage. While hydrogen enables the vehicle itself to be zero-emission, the production chain still has a carbon footprint.
Fortunately, there are some alternatives.
The first is electrolysis. The crucial thing about this method of hydrogen production for shipping is that it can be done on-board, using wind and solar energy to create hydrogen on the go. This means that a ship equipped to produce its own hydrogen needs a much smaller space to house the hydrogen storage cylinders, and can ultimately become self-sufficient in terms of fuel.
Another option is to convert the hydrogen into ammonia for storage. Ammonia takes up much less volume than hydrogen, and does not require cryogenic storage. The ammonia can be converted back to hydrogen on-board. Ammonia is toxic to humans and sea life, so extra care must be taken if using this method.
In addition, maritime hydrogen infrastructure is growing. Many prototypes use on-board hydrogen production methods, but mobile hydrogen refuelling stations have also been in use. Waterside refuelling stations are an option for canal and river boats.
This is by far the biggest sector when it comes to maritime emissions, and therefore presents the greatest challenge to hydrogen conversion. Research has shown that hydrogen is nonetheless a viable fuel source for shipping.
The chance of success depends on several factors, from government regulations and funding to the technologies available. One report has found that the shipping sector could feasibly completely decarbonise by 2035 using a range of green technology solutions, including hydrogen.
Scalability is a problem for large shipping vessels, as the entire fuel system must be scaled up to produce enough power for large ships. This potentially cuts into storage space and produces additional logistical considerations. That said, a study by the ICCT has concluded that hydrogen fuel systems could be incorporated on-board cargo ships with minimal disruption to normal service if done efficiently.
Thus far, wide-scale prototyping aboard commercial shipping vehicles is in its infancy. But all players agree that conversion to green fuels is essential in order to meet global carbon emission goals.
Meanwhile, smaller ships are being used as test subjects for hydrogen fuel with a great deal of success.