The use of ammonia as a maritime fuel has been heralded as a potential game-changer in the quest for zero-emission shipping. Ammonia, when burned, does not emit carbon dioxide, positioning it as an attractive alternative to conventional fuels in an industry under increasing pressure to decarbonize. However, the latest findings from ClassNK, a leading classification society, cast a shadow of doubt over the practicalities and safety of ammonia-fueled ships, with their newly published estimates of ammonia leak frequencies from onboard components triggering renewed scrutiny.
ClassNK has introduced these estimated leak frequencies as a crucial part of risk assessment protocols for ammonia-fueled ships. The figures are detailed in an appendix to ‘Part C of Guidelines for Ships Using Alternative Fuels (Edition 3.0),’ and they are intended to provide a foundation for more accurate risk evaluations. Yet, while these estimates represent a step forward in understanding the potential risks associated with ammonia as a fuel, they also highlight a critical challenge: the inherent dangers posed by ammonia leaks onboard ships, which could undermine its promise as a sustainable maritime fuel.
Ammonia is increasingly considered as a viable alternative due to its zero-carbon emission profile, but its adoption has been slowed by concerns over its toxicity and potential for leaks. The chemical is highly corrosive and poses significant health risks upon exposure, including irritation of the eyes, skin, and respiratory system, and in high concentrations, it can be fatal. Despite these risks, the maritime industry has pushed forward, with various studies and technological developments aimed at making ammonia-fueled ships a reality. However, the ability to mitigate the risks associated with ammonia leaks remains a significant hurdle.
The new leak frequency estimates published by ClassNK aim to support the design and operation of these ships by offering data for more thorough risk assessments. Yet, until now, there has been a notable lack of statistical data on ammonia leaks from onboard components, making accurate risk estimation difficult. In response, ClassNK, in partnership with the Research Institute of Science for Safety and Sustainability (RISS) of the National Institute of Advanced Industrial Science and Technology (AIST), undertook a probability estimation of ammonia leaks using a Bayesian method. This approach combined data on ammonia leaks from onshore facilities in Japan, sourced from the High Pressure Gas Safety Institute of Japan, with data on liquefied natural gas (LNG) leaks from LNG-fueled ships.
Ammonia as an alternative maritime fuel faces scrutiny as ClassNK publishes leak frequency estimates, questioning its viability and safety.
By applying the Bayesian method to estimate the probability of ammonia leaks from various components onboard ships, ClassNK is attempting to create a more reliable framework for risk assessment, even in the absence of extensive operational data. This method has previously been applied to other substances with limited usage data, such as hydrogen, but this marks the first attempt globally to estimate ammonia leak frequencies for onboard components of ammonia-fueled ships. While the use of this methodology is innovative, it also underscores a critical limitation: the lack of real-world data on ammonia leaks in maritime environments.
These findings suggest that while ammonia may hold potential as a low-carbon fuel, the safety risks remain a significant concern. The ammonia leak frequencies, derived from data on similar but not identical conditions (i.e., onshore ammonia facilities and LNG-fueled ships), raise questions about how directly applicable these estimates are to the complex and often unpredictable environment of a seafaring vessel. Furthermore, using data from onshore facilities might not fully account for the unique challenges faced at sea, such as varying weather conditions, temperature fluctuations, and the constant movement of the ship, all of which could affect the likelihood and impact of a leak.
Despite these challenges, ClassNK’s initiative is part of a broader effort to promote the safe use of ammonia and other alternative fuels under its ‘Transition Support Services,’ which aim to help the maritime industry move towards zero-emission solutions. The classification society has positioned these guidelines as a crucial resource for stakeholders considering the adoption of ammonia as a fuel, offering a means to better understand and mitigate the associated risks. Yet, the question remains: are these measures enough to overcome the safety hurdles and make ammonia a viable alternative fuel for shipping?
Critics argue that while efforts like those from ClassNK are commendable, they may still not provide sufficient assurance of safety, especially given the limitations of the available data. The potential consequences of ammonia leaks—ranging from minor exposure incidents to catastrophic failures—could have severe repercussions not only for the crew and the ship but also for the broader marine environment. Therefore, the industry must proceed with caution, ensuring that robust safety protocols, rigorous testing, and comprehensive risk assessments are in place before ammonia-fueled ships become commonplace.
The publication of the leak frequency estimates by ClassNK could be seen as both a wake-up call and a necessary step forward. It highlights the need for more extensive research, greater transparency, and a cautious approach in the drive to adopt alternative fuels like ammonia. As the maritime industry continues to explore cleaner fuel options, it is essential to balance environmental benefits with safety considerations, ensuring that the shift towards sustainability does not come at the cost of increased risks to human life and the marine ecosystem.
ClassNK’s guidelines, available for download via their website, provide an essential tool for those involved in designing, building, and operating ammonia-fueled ships. However, as the debate continues over the viability of ammonia as a maritime fuel, the industry must grapple with the complexities and risks inherent in this transition. For ammonia to become a truly viable alternative, it must be accompanied by assurances that its use will not compromise the safety of those at sea or the environment they navigate. The road to zero-emission shipping may be paved with innovative solutions, but it must also be navigated with caution, guided by rigorous science and an unwavering commitment to safety.
