The shipping industry is following other sectors in the drive to decarbonise, with ammonia-powered propulsion offering a potential pathway to meeting the International Maritime Organisation’s 2050 climate target.
After the recent introduction of the IMO 2020 0.5pc sulphur cap in marine fuel, the shipping industry seems to be preparing for its next great regulatory challenge — the IMO’s target to halve the sector’s CO2 emissions from 2008 levels by 2050. There is currently no commercially available technology to comply with the 2050 regulation, but several companies are looking at ammonia as a potential zero-carbon marine fuel.
Two different coalitions of companies have already announced plans this year to introduce ammonia-powered propulsion. Malaysia-based shipowner MISC, Samsung Heavy Industries (SHI), Lloyd’s Register and MAN Energy Solutions announced on 16 January that they have joined forces, and a few days later Norwegian oil firm Equinor and marine technology operator Eidesvik launched a research project to retrofit the Viking Energy supply vessel to run on ammonia by 2024.
Ammonia benefits
For now, there are two zero-carbon marine fuels that research suggests would be viable — hydrogen fuel cells and ammonia. With the combustion of pure ammonia or generation of electric power in a fuel cell using hydrogen, emissions are restricted to water vapours and hot air. But ammonia has advantages over hydrogen. Ammonia is harder to ignite and non-explosive, in contrast to highly explosive hydrogen. Ammonia also has a higher — around 70pc — volumetric energy density than hydrogen, and is significantly easier to liquify for storage and transportation, making ammonia more cost-effective. Stored ammonia also has the advantage that it can be cracked into nitrogen and hydrogen, with the latter then potentially being used as a fuel itself. Ammonia is already used as fertilizer and for immediate power generation, with existing infrastructure in place for transport, storage and distribution, and vessels that specialise in carrying ammonia are already in operation. Ammonia-carrying vessels are likely to be the first to be retrofitted with technology to use ammonia as a marine fuel.
Ammonia drawbacks
Ammonia requires specific expertise to handle and store as well as auxiliary equipment both on board and at bunkering stations, making it harder to introduce to vessels outside of ammonia carriers and the LPG carriers that occasionally transport it. The compound is also highly toxic and can be lethal to humans after more than 10 minutes of exposure. Ammonia is lighter than air when in a gaseous state so will not settle in low-lying areas, although in the presence of high relative humidity the vapours formed are heavier than air and could settle in places with poor air flow.
Ammonia is currently produced using fossil fuels, and so cannot be considered to be truly zero-carbon. Research into “green” ammonia production suggests one option could be the electrolysis of water using renewably generated electricity. A scientific report from 2012 proposed one-step synthesis of ammonia using air and water at room temperature and normal air pressure in an effort to break the link between ammonia and fossil fuels. The study concluded that the method is renewable, sustainable and flexible in scale and location. The lack of “green” ammonia production at this stage would also suggest possible refuelling and pricing issues as the supply and demand dynamics are not yet clear.
Pushing zero emissions
Several initiatives promoting zero-carbon shipping were launched last year, with some identifying ammonia as the solution. The UK Department of Transport’s Clean Maritime Plan includes decarbonisation targets, although they are “aspirational” rather than mandatory, and a £1mn prize for “innovative ways to reduce maritime emissions". A coalition of 11 banks created the Poseidon Principles to provide a global framework for climate-aligned ship financing. The American Bureau of Shipping (ABS) classification society launched a “global sustainability centre” to help shipping transition to a low-carbon economy. The centre’s objectives include studying the viability of alternative fuels and analysis of “de-carbonisation pathways”. Finally, a group of over 90 companies from the maritime, energy, infrastructure and finance sectors formed the Getting to Zero coalition that aims to provide deep-sea zero-emission solutions by 2030.
One engine maker forecasts that dual fuel retrofit or ammonia-ready engines for newbuild vessels could be developed in the next 2-4 years. And some researchers have proposed that a mixture of ammonia and hydrogen would be a more viable solution instead of using pure ammonia, as this could mitigate some of the combustion deficiencies that ammonia exhibits.
Green goal
There is a strong drive towards “green” shipping and following the uncertainty resulting from the implementation of IMO 2020, the preparation for coming regulation seems to be more intensive and already well under way. Financial institutions, governments, international organisation and public opinion, along with the eventual costs of any new technology, will be the main drivers in the move towards a more environmentally friendly shipping industry. Much of the industry already seems to have decided that the most promising technology to achieve targets such as IMO 2050 is ammonia, although there is also still interest in hydrogen as well. For instance, France-based container company CMA CGM has joined forces with Energy Observer to develop hydrogen, solar, tidal and wind power for vessels, with hydrogen as the primary objective.