Hydrogen is the most famous fuel that is not based on a fossil basis. Another non-fossil fuel is ammonia. This fuel is classified as synthetic fuels, just like methanol (synthetic, but fossil). These two synthetic fuels are not yet known but have a lot of potential. In part 4 on alternative marine fuels, the pros and cons of these two products are discussed.
Both LNG and hydrogen have the disadvantage that they become liquid at a very low temperature (-162 degrees Celsius and -253 degrees Celsius, respectively). Another gas, ammonia, liquefies at -34 degrees Celsius, or at room temperature under high pressure (10 bar). In addition, ammonia has a higher density than liquid hydrogen, which means that storage takes up less space than hydrogen. However, compared to HFSO, ammonia weighs nearly twice as much and requires three times as much space to generate the same amount of energy.
In any case, ammonia has been in the spotlight for some time as an alternative fuel. But how realistic is the use of ammonia as marine fuel?
Various investigations have been carried out or are ongoing into the use of ammonia. In the DNV GL Energy Transition Outlook 2018, Maritime Forecast to 2050 study from October 2018, DNV GL estimates ammonia as a fuel as the “best estimate future”. Lloyd’s Register identified ammonia in its December 2017 report “Lloyd’s Register, Zero-Emission Vessels 2030” as “the most competitive” fuel with zero emissions. The International Transport Forum, part of OECD, also concluded in its report “Decarbonizing Maritime Transport, Pathways to zero-carbon shipping by 2035”, that the sector will be able to make a major leap in 2035 with carbon-free sailing if use is made of a mix of ammonia-hydrogen fuel.
The Dutch ship design and engineering company C-Job Naval Architects has conducted research into the use of ammonia as a fuel. For a number of years, C-Job believes that ammonia can be a viable and promising option as a clean and sustainable fuel. The investigation was based on an ammonia tanker operating on its own cargo.
This assumption stems from the experiences of sailing on LNG: the first ship that sailed on LNG was an LNG tanker simply because the LNG storage was already available, and it was a relatively small step to start sailing on it itself. The same can apply to ammonia tankers. Ammonia is transported in LPG tankers for the fertilizer industry. In principle, these ships can use their cargo as fuel.
MAN Energy Solutions is currently investigating the possibilities of an engine that runs on ammonia. Technically, the use of this fuel is possible, but since ammonia is very toxic, and according to the “International Code of Construction and Equipment or Ships Carrying Liquefied Gases in Bulk” (the IGC Code) it is prohibited to use toxic substances as fuel. There are still quite a few hooks and eyes attached to it before ammonia will break through as a fuel.
However, due to the importance of ammonia as a raw material for manure production, ships already have extensive experience with ammonia, both in storage for transport and in cooling on board. There is also a lot of experience with the production, handling and safety of ammonia in the industry. There is sound regulation in this sector. These regulations can serve as a basis for legislation regarding the use of ammonia as a fuel.
Moreover, if ammonia does indeed become the choice of shipping for carbon-free fuel, it will require around 200 million tons of ammonia annually, and that is more than is currently being produced worldwide.
Methanol is also a potential emission-free marine fuel. In the Netherlands, the sector-wide Green Maritime Methanol project will investigate the opportunities of methanol as a sustainable alternative marine fuel. In addition to shipowners, shipbuilders, engine manufacturers and specialized service providers such as Boskalis, the Koninklijke Marine, Van Oord and Wagenborg, Damen Shipyards, Feadship and Royal IHC, engine manufacturers Pon Power and Wärtsilä, Marine Service Noord and C-Job Naval Architects also carry the ports of Rotterdam and Amsterdam, research centers of TNO, TU Delft, NLDA and Marin and methonall suppliers BioMCN, Helm Proman and the international trade association Methanol Institute are contributing to the research.
The project has a duration of two years. As part of the project, partners will explore concrete options for the use of methanol as a maritime transport fuel for both new-build vessels and conversions.
Stena Line has been using methanol since 2015. The Stena Germanica, the connection between Gothenburg and Kiel, uses a fuel mix including methanol. Stena Line has converted the ship, which can carry 1,500 passengers, for this. The Stena Germanica dates from 2001, the Finnish company Wärtsilä has made a conversion kit for the 32,000 horsepower engines of the Germ. The operation costs € 22 million.
Since 2016, two Methanex Corporation sea-going vessels have been operating on dual-fuel methanol engines, trendsetters within the methanol-powered vessels. The first 10,000 cruising hours are over – the engine comes from MAN.
In part 5 we look further at technological solutions to reduce sulfur and nitrate emissions.