Issuing agency: Bureau Veritas Marine & Offshore
Column:Future Fuel
source: https://marine-offshore.bureauveritas.com/shipping-decarbonization/future-fuels/ammonia
Ammonia is a widely traded chemical commodity that has long been transported in liquefied petroleum gas (LPG) tankers, which are also able to carry ammonia.However, ammonia also presents challenges: it is toxic at low concentrations, presenting health and safety concerns for crew members. To use ammonia onboard, shipowners must ensure it is handled safely in compliance with applicable requirements. When transported as cargo, ammonia is regulated through the IGC Code. For ships looking to use ammonia as fuel, design requirements can be found March 2023 issue of NR 671 Rules. The design will have to be assessed through Alternative Design procedure of the IGF Code and SOLAS regulations.
There are several advantages to using ammonia as a marine fuel:
To help de-risk ammonia as fuel, Bureau Veritas is building on our tried-and-tested approach in supporting the development of liquefied natural gas (LNG). Our experts have already released tentative Rules for ammonia as fuel (NR 671). This will guide shipowners toward safe onboard transportation and consumption. Ships converting to using ammonia as fuel can take advantage of our AMMONIAFUEL-PREPARED notation.
Providing technical and regulatory expertise, Bureau Veritas is a partner of choice for maritime experts developing ammonia as fuel. Among our many projects, we have collaborated with TotalEnergies to study ammonia leak mitigation and treatment onboard, addressing key safety concerns for ammonia as fuel.
There are currently no in-service ships using ammonia as fuel. Ammonia-fueled engines are not yet commercially available, and no existing vessels are equipped for ammonia propulsion. However, two-stroke and four-stroke ammonia fueled engines are under development, as are regulations for handling ammonia as fuel.
Ammonia can be stored under pressure at atmospheric temperature or in a refrigerated state. This means that ships using ammonia as fuel and bunkering vessels may carry different combinations of pressurized, semi-refrigerated or fully refrigerated ammonia. To ensure safe and successful bunkering operations, ships require specific equipment (e.g., compressors, heat exchangers, vapor return systems) and must follow detailed bunkering procedures
Ammonia can be a zero-carbon fuel from a well-to-wake perspective if it is produced from air and water using renewable energy. This is then known as “green ammonia.” Brown ammonia is produced using fossil fuels and is therefore not a zero-carbon fuel from a well-to-wake perspective.
Green ammonia is also known as e-ammonia. It is produced via the Haber-Bosch process, which converts green hydrogen and nitrogen into ammonia. Other methods for producing green ammonia – such as electrochemical nitrogen reduction – are under development, but will take time to mature and become industrialized.
From a well-to-wake perspective, only green ammonia or e-ammonia can be considered carbon-free. Ammonia produced from fossil fuels in fact has a worse well-to-wake emissions footprint than heavy fuel oil. To truly decarbonize shipping, ammonia must be produced from renewable energy and a low-carbon supply chain.
It is unlikely that green ammonia will be ready for use by the time CII compliance is required. For now, short-term measures such as improving energy efficiency or using low-carbon fuels are better solutions. In the long-term, however, green ammonia may be a route to compliance, particularly if IMO regulations evolve to take a well-to-wake approach to emissions.
While fossil fuel-based ammonia is cheap and widely traded, green ammonia is expensive and in short supply. From a production perspective, increasing green ammonia will require the scaling up of renewable energy infrastructure for green hydrogen. From a market perspective, the price of green ammonia will depend on competition from other sectors, making costs hard to predict. Beyond this, shipowners must also factor in the costs of integrating technology onboard and training crew in safe ammonia handling.