Developing ammonia: the marine approach to a zero-carbon fuel
Improving the sustainability of the global fleet is a top priority for stakeholders across the marine industry, and a practicable goal for the International Maritime Organization (IMO). To accomplish this, IMO has set ambitious targets for the reduction of greenhouse gases from shipping, with major emissions reduction dates planned for 2030 and 2050. This means shipowners and managers must find cleaner ways to fuel their vessels, such as mixing or replacing fossil fuel-based oil with low- or zero-carbon fuels.
Ammonia is among the top contenders for fuel of the future. It is a zero-carbon fuel, and when produced using green hydrogen from renewable energy, can be a net zero fuel. Ammonia is already transported by ship as cargo, meaning many marine actors are familiar with its use and handling. Moreover, existing production and storage terminals at ports worldwide give ammonia an edge, making ship-to-ship and ship-to-shore bunkering infrastructure easier to develop.
However, there are still a handful of challenges that the marine industry must overcome before shipowners can safely use ammonia as fuel. These range from questions of risk and safety, to regulatory concerns, to assessing all aspects of ammonia’s sustainability as a fuel.
Five areas of ammonia development
Maritime stakeholders are currently addressing five key areas of development for ammonia, which will enable its use as fuel safely, regularly and at scale.
Ammonia is a toxic substance that can be lethal following exposure beyond a certain threshold. Ship designers and shipyards need to rethink the design of fuel storage, distribution, gas handling and bunkering systems to prevent and detect leaks during operations. Ventilation systems must also be carefully designed to avoid the spread of ammonia vapors, capturing any potential leaks or emissions from exhaust.
For ammonia to be a truly zero-carbon fuel, it must be produced as part of a sustainable supply chain. For ammonia producers, this means having access to renewable energy sources – such as wind or solar power – and using the carbon-free process of electrolysis to develop ammonia. Following production, shipowners also need to address onboard sustainability questions, such as how to avoid ammonia slip and how to manage nitrous oxide emissions.
Chief Commercial Director
Bureau Veritas Marine & Offshore
Ammonia still presents a number of challenges, but the shipping industry is dedicated to working to advance the use of this zero-carbon solution. It will have a major role to play – alongside other alternative fuels and propulsion systems – in decarbonizing the marine sector and helping all stakeholders build a sustainable future for shipping.
Ammonia has a lower energy density than other fuels – about half that of liquefied natural gas, and less than third that of standard fuel oil. Vessels therefore need to carry substantial amounts of ammonia onboard to sail over long distances or allow for frequent bunkering stops. This presents a design and engineering challenge for newbuilds, and particularly when retrofitting in-service vessels.
For the moment, it is difficult to predict the future cost of ammonia as fuel, as the market is still premature. However, from an energy perspective, ammonia is already more expensive than heavy fuel oil, and green ammonia is expected to cost more than brown ammonia. As a recent report by chemical expert Haldor Topsøe shows, green ammonia is predicted to cost $350-400 USD/MT initially, later dropping to $250 USD/MT – about the current price of brown ammonia.
This process could potentially be accelerated with the development of carbon taxes or incentives from national governments. There are some signs of this coming, such as the European Commission seeking to include marine shipping in the European Emissions Trading Scheme.
For the moment, the technology for ammonia-fueled ships is ahead of relevant regulations. There is currently no international legislation covering the use of ammonia as a marine fuel.
How the maritime ecosystem is developing ammonia
The marine sector is full steam ahead on finding solutions to the challenges of ammonia, with each set of stakeholders playing its part. Their goal is to make green ammonia more accessible as a marine fuel and less expensive, with research focused on increasing access to renewable energy. The marine industry will do this in collaboration with agricultural stakeholders, who currently dominate the ammonia market.
Technology providers across Europe are developing solutions for onboard ammonia use, adapting existing dual-fuel engines and storage systems to make them ammonia compatible. A joint industry project (JIP) consisting of shipowners, classification societies, energy providers and equipment manufacturers is working to improve safety for ammonia as fuel. A crucial workshop took place in 2020 to assess hazard identification (HAZID) for an ammonia-fueled very large crude carrier. A follow-up workshop will take place in September 2021 in Copenhagen, with a focus on hazard and operability studies (HAZOP) for the same vessel.
Bureau Veritas boosts ammonia as fuel
As a leading classification society, Bureau Veritas is keen to support shipowners in their transition to using ammonia as safely and sustainably as possible.
Our AMMONIA-PREPARED notation for newbuilds certifies that a ship has been designed and constructed with a view to future conversion to using ammonia as fuel. In parallel, we have published Rule Note NR 671, developed in collaboration with shipowners, charterers and marine stakeholders, including fuel handling system and engines manufacturers. The rule covers safety aspects of managing ammonia in storage tanks, fuel-piping systems and gas handling systems, during bunkering, and the distribution of ammonia to dual-fuel engines.
Bureau Veritas is also part of numerous JIPs for ammonia carriers, ammonia-fueled vessels and cruise ship conversions for vessels switching from LNG to ammonia. We are participating in the design of a large, ammonia-powered cargo ship, and recently delivered an Approval in Principle for a GTT ammonia storage system.
Finally, Bureau Veritas is a member of the International Association of Ammonia Energy, playing an active role in preparing ammonia for use as fuel.
IMO expects a reduction of at least 40% in CO2 emissions per transport work as compared to 2008 levels by 2030, and a 70% reduction by 2050. IMO also expects total annual greenhouse gas (GHG) emissions from shipping to be at least halved by 2050.
 I.e., per energy unit
Black ammonia is produced with natural gas, making it lower carbon than ammonia produced using coal, but less sustainable than green ammonia.
 Ammonfuel – an industrial view of ammonia as fuel. Haldor Topsøe. August 2020.