Exercise Caution With Ammonia Switch, Warns New Study

A new study from the Massachusetts Institute of Technology (MIT) has thrown a spanner into the plan to transition ships from diesel fuel to ammonia. While ammonia offers the alluring prospect of slashing greenhouse gas emissions, MIT researchers warn that without stricter regulations, the switch could come at a cost to human health, reports Baltic Exchange.

The problem lies in the unwanted guests that appear when ammonia burns. Unlike diesel, burning ammonia creates nitrous oxide, a greenhouse gas with a staying power 300 times greater than carbon dioxide, as quoted in the MIT study by lead author Anthony Wong. This translates to a magnified heat-trapping effect, potentially negating some of the climate benefits ammonia offers.

Additionally, ammonia combustion produces nitrogen oxides (NOx), a key player in smog formation and fine particulate matter generation. These pollutants can exacerbate respiratory problems, increasing the risk of heart attacks, strokes, and asthma. The study paints a sobering picture: under current regulations, a global shift to ammonia fuel could result in a staggering 600,000 additional premature deaths annually, according to the MIT research team.

However, the MIT study doesn’t entirely dismiss ammonia’s potential. Green ammonia, produced using renewable energy sources, offers a near-zero carbon footprint, representing a significant improvement over traditional diesel fuel. Even without stricter regulations, cleaner burning engines could provide some mitigation, potentially reducing premature deaths from shipping emissions by 20,000 compared with current levels, as indicated by the study’s findings. With robust regulations and a commitment to developing clean technology, that number could plummet to a total reduction of 66,000 deaths, according to the MIT researchers.

Comprehensive approach

In the report, Wong emphasised the need for a comprehensive approach that considers both climate change and public health impacts. “Not all climate solutions are created equal. There is almost always some price to pay. We have to take a more holistic approach and consider all the costs and benefits of different climate solutions, rather than just their potential to decarbonise,” said Wong, a postdoc in the MIT Center for Global Change Science. “Saying that ammonia is a ‘clean’ fuel is a bit of an overstretch. Just because it is carbon-free doesn’t necessarily mean it is clean and good for public health.”

Regulations are crucial to limit ammonia emissions and incentivise the industry to embrace clean technologies. This could involve promoting cleaner burning engines or even exploring technologies that combine ammonia with hydrogen for improved combustion efficiency, the MIT study suggests.

The study did, however, acknowledge the limitations of data from real-world, ammonia-powered ships. Researchers are calling for collaboration with the maritime industry to share engine data, allowing for more accurate assessments of both climate and health impacts.

Policymakers also have a critical role to play. The study urges them to update shipping emission regulations to address potential air quality concerns, building on the findings presented in the MIT research.

The impact of this shift won’t be felt uniformly across the globe, the report adds. East Asia, already burdened with existing air pollution issues and heavy shipping traffic, could be particularly vulnerable to health risks. The study therefore underscores the need for global strategies tailored to the specific circumstances of different regions. This may involve stricter regulations or even financial incentives for cleaner technologies in areas disproportionately affected by air pollution, as recommended by the MIT research team.

“Development and enforcement of new NH₃ emission regulations is critical for ammonia-powered ships to provide positive impact on air quality and prevent negative impacts from excessive nitrogen deposition, alongside reducing GHG emissions,” said the report.

Path ahead

While acknowledging the potential downsides of ammonia fuel, the MIT research suggests that by taking proactive steps to mitigate air quality concerns through stricter regulations, industry collaboration, and targeted regional strategies, the industry can unlock its potential as a viable solution for cleaner shipping in the future.

However, MIT recognises that the path forward is a delicate balancing act – one that prioritises slashing greenhouse gas emissions without compromising public health.

The study also highlights the need for transparency and data sharing. Collaboration between researchers and the maritime industry is crucial for obtaining real-world data from operational ammonia-powered ships. This data would allow for more accurate assessments of the climate and health impacts associated with a large-scale switch to ammonia fuel.

The financial implications for the industry also need to be considered. Stricter regulations and the development of clean technologies will come at a cost and therefore economic incentives and targeted financial support need to be explored to help the industry transition smoothly and encourage investment in clean technologies.

“We find that the public health impacts of switching from fossil fuel to ammonia depends largely on the technology and policy choices,” concludes the report. “If tuned to balance NOx and NH₃ concentration from engine exhaust to allow simultaneous reduction of NOx and NH₃ emissions using well-optimised exhaust post treatment systems with highly efficient combustion modes, deployment of ammonia combustion technology can lead to net health benefits by reducing both O₃ and PM2.5 levels.”