Marine fuel (HFO - heavy fuel oil - also known as bottom-of-the-barrel) is close to the dirtiest on earth. As a result the shipping industry produces 9% of all CO2 that is released to the atmosphere.

The International Chamber of Shipping, which represents more than 80% of the world merchant fleet, has promised to literally “clean up” its act and reduce the carbon footprint of marine transport. But how? Some "green" fuels are beckoning on the horizon such as formic acid (reported on earlier here), ammonia (reported on earlier here), biofuels and hydrogen. Biofuels are unlikely candidates because their limited availability will force adoption in markets that value energy density, like aviation. Hydrogen has the opposite problem: storing it needs so much space, that it would displace too much cargo.

Ammonia has for decades been safely transported by sea in ships up to 60,000 tons, as mentioned in the shipping magazine Schuttevaer. There are already loading and unloading points for ammonia tankers as well as a distribution network. To prove that ammonia can be a technological, economical and safe alternative maritime fuel, a consortium has been formed, consisting of Future Proof Shipping (non-profit venture), C-Job (naval architects), Proton Ventures, (ammonia engineering specialist) and Yara (global ammonia producer). They started a project to explore ammonia’s propulsion potential, both as a fuel for combustion engines and as a power source for fuel cells. Click here for more details on this project.

Using green ammonia sounds good, but first it has to be made. Now ThyssenKrupp announced that it was moving forward with a demonstration plant in Port Lincoln, South Australia. The Port Lincoln facility will include a 30MW water electrolysis plant and an ammonia production facility with a capacity of 50 tons per day. Both plants will be based on ThyssenKrupp technology. The product will be used as fertilizer; the plant is after all only a meant to demonstrate that everything can work together.

Producing green ammonia at high P and T as with the century-old Haber-Bosch process or the Uhde process of ThyssenKrupp is not all that green.But a development in Australia, reported in Science magazine, shows promise. In a reverse fuel cell with an ionic liquid electrolyte and a proton-permeable membrane water and nitrogen are fed and ammonia comes out.