why did the us ban ammonia engines

2 min read 02-12-2024

The claim that the US banned ammonia engines is inaccurate. There was never a sweeping federal ban prohibiting their use. However, their adoption was severely limited, primarily due to practical challenges rather than outright legal prohibition. Let's examine the factors that hindered the widespread use of ammonia engines in the United States.

The Allure and the Challenges of Ammonia Power

Ammonia (NH₃), a readily available chemical compound, possesses attractive qualities as a fuel: it's readily combustible, burns cleanly (producing only nitrogen and water vapor), and is relatively inexpensive. These properties led to some experimentation with ammonia engines, particularly in the early to mid-20th century.

However, several significant obstacles proved insurmountable for widespread adoption:

1. Material Compatibility and Corrosion:

Ammonia is highly corrosive to many common engine materials. This necessitated the use of specialized, often expensive alloys and components, significantly increasing the cost of manufacturing and maintenance. The challenges in material science at the time proved too significant to overcome cost-effectively.

2. Energy Density and Storage:

Compared to gasoline or diesel, ammonia has a lower energy density. This means a larger tank is needed to store the same amount of usable energy, impacting vehicle size and performance. Efficient and safe storage systems were underdeveloped during the periods of most interest in ammonia engines.

3. Toxicity and Handling:

While ammonia combustion products are relatively benign, ammonia itself is toxic in concentrated forms. Leaks could pose significant safety risks, requiring sophisticated safety systems and specialized handling procedures. This added complexity and cost were considerable deterrents.

4. Infrastructure and Distribution:

The existing fuel infrastructure was geared towards gasoline and diesel. Establishing a widespread distribution network for ammonia would have demanded substantial investment and logistical changes. This was a significant barrier to market entry.

Why Other Fuels Prevailed

The difficulties associated with ammonia engines, coupled with the concurrent advancements and refinement of gasoline and diesel technologies, led to the practical abandonment of ammonia power in the United States. The combination of cost-effectiveness, established infrastructure, and readily available fuel sources cemented the dominance of internal combustion engines using gasoline and diesel fuels.

Conclusion

The absence of a US ban on ammonia engines doesn't imply their suitability or viability. Instead, the lack of widespread adoption is a result of a complex interplay of technological, economic, and safety challenges that, for the most part, remain largely unaddressed today. While interest in alternative fuels is renewed, ammonia faces the same fundamental hurdles that prevented its successful competition with petrol and diesel decades ago.