AMMONIA, with its potential for zero-carbon emissions, is viewed as a promising alternative fuel for decarbonising global industries. Despite challenges in production, transportation and usage, advances in the ammonia landscape, particularly for maritime, are progressing quickly.

Why ammonia is considered a future fuel

The impact of alternative fuels depends significantly on production methods. Ammonia, made from hydrogen and nitrogen, is a potential zero-carbon fuel but is mostly produced as “grey” ammonia, which relies on fossil fuels, generating high emissions.

Efforts are underway to shift to low-carbon ammonia production methods, specifically “blue” ammonia, produced with carbon-capture technology, and “green” ammonia, created through renewable energy and electrolysis. These versions align with low-carbon goals and position ammonia as a viable decarbonised fuel.

While the maritime industry considers ammonia a future fuel, its primary use remains industrial — primarily in fertiliser, plastics and synthetic fibres. As production scales for blue and green ammonia, the maritime industry’s role in global ammonia transport will grow significantly.

Challenges of ammonia as fuel

Ammonia is highly toxic, posing risks in transport and use, with potential leaks threatening both people and ecosystems. Additionally, its energy density is much lower than conventional fuels, meaning larger volumes are required, which demands expanded shipping capacity. Ammonia tanks and carriers also need specific materials to prevent stress corrosion, and safety gear is essential for personnel.

Building an efficient transport network is critical because blue and green ammonia are often produced in separate locations than grey ammonia, thus requiring new routes and infrastructure.

Current ammonia transport in maritime

The maritime industry is addressing ammonia transport challenges. Currently, about 500 “ammonia-capable” carriers, derived from the LPG fleet of around 1,600 ships, manage ammonia transport, though only a portion is actively used for this purpose.

Ammonia can be transported as a liquid in two ways:

In fully refrigerated Type A tanks at -33°C for medium- and large-sized carriers.

In Type C tanks that use pressure and temperature adjustments, typically for smaller ships.

Innovative technology developments are underway, including membrane systems for ammonia transport, although further assessments are needed regarding sloshing and insulation compatibility.

The evolution of LNG carriers offers insights for ammonia’s future.

Bureau Veritas, leveraging its experience in LNG, is exploring concept designs for larger ammonia carriers, potentially up to 200,000 cu m. Although challenges remain for these larger carriers, advancements could reduce transportation costs and improve the environmental footprint. However, such large ships require enhanced onshore infrastructure.

With decades of LNG expertise, Bureau Veritas is well equipped to guide the ammonia sector’s development. As a leader in LNG classification, Bureau Veritas supports the ammonia industry’s growth through new technological developments, including approval for ammonia bunkering vessel designs and collaborations on ammonia fuel-ready ship projects.

Carlos Guerrero, global market leader for Gas Carriers at Bureau Veritas Marine & Offshore, said, “We are committed to supporting maritime’s transition to greener fuels, including ammonia, by developing classification Rules, conducting risk analyses, and verifying safety and sustainability standards.”

Ammonia as a fuel: prospects and challenges

Currently, ammonia’s toxicity prevents its use as fuel under the International Maritime Organization’s IGC Code. However, the IMO is revisiting regulations to potentially allow its use. Technical advances are needed for ammonia to serve as fuel, including innovations in combustion engines that minimise emissions while addressing the high energy required for ammonia combustion.

Bureau Veritas has prepared rules and notations in anticipation of ammonia’s approval as fuel, ready to certify engines and technologies needed to integrate ammonia into maritime energy solutions.