Many countries and industries, including the maritime industry, are researching using ammonia as a fuel because ammonia could be a carbon-free fuel source. Government incentives have increased the investment into the supply chain needed to create “green ammonia,” or ammonia produced without using carbon. Although ammonia is being developed for many different applications, one of the first applications will likely be as fuel for maritime transport.
Current developments in ammonia fuel
For example, a converted offshore vessel, Fortescue Green Pioneer, has been retrofitted with an ammonia engine and fuel systems. Multiple shipping companies have ordered the production of ammonia-fueled vessels, including four ships for Maersk and six for Trafigura.
Because the shipping industry accounts for 2% of global emissions, a wholesale change in fueling the maritime industry could make a significant difference in reducing carbon emissions and serve as a prototype for other applications.
Challenges and concerns with ammonia as a fuel
But this promise is not without obstacles. Ammonia is corrosive, and green ammonia is more expensive to produce than its fossil fuel-made counterparts. Burning ammonia, while carbon-free, does produce nitrogen oxide. Finally, ammonia poses unique safety risks due to its toxicity.
Toxicity and safety risks of ammonia
Ammonia is toxic. The U.S. Occupational Safety and Health Administration (OSHA) has set a 15-minute exposure limit for gaseous ammonia of 35 parts per million (ppm) by volume in the environmental air and an 8-hour exposure limit of 25 ppm by volume.
The National Institute for Occupational Safety and Health (NIOSH) has set the IDLH (Immediately Dangerous to Life and Health, the level to which a healthy worker can be exposed for 30 minutes without suffering irreversible health effects) to 300 ppm. Liquid ammonia can also cause caustic burns.
Ammonia vapor has a sharp, irritating, pungent odor that acts as a warning of potentially dangerous exposure. The average odor threshold is 5 ppm. While the odor is below any danger or damage, failure to safely address the source of the ammonia or don personal protective equipment (PPE) could result in lung damage or death.
