‘Green ammonia’ could decarbonize shipping: study

University of Oxford – A study published on Jan. 9 found that green ammonia could be used to fulfill the fuel demands of over 60 per cent of global shipping by targeting just the top 10 regional fuel ports.

Researchers at the Environmental Change Institute (ECI) at the University of Oxford looked at the production costs of ammonia which are similar to very low sulphur fuels, and concluded that the fuel could be a viable option to help decarbonize international shipping by 2050.

Around US$2 trillion will be needed to transition to a green ammonia fuel supply chain by 2050, primarily to finance supply infrastructure. The study shows that the greatest investment need is in Australia, with large production clusters also predicted in Chile, California, North-West Africa and the southern Arabian Peninsula.

Ninety per cent of the world’s physical goods trade are transported by ships that burn heavy fuel oil and emit toxic pollutants. This accounts for nearly three per cent of the global greenhouse gas (GHG) emissions. As a result of this, the International Maritime Organization (IMO) committed to decarbonizing international shipping in 2018, aiming to halve GHG emissions by 2050. These targets have been recently revised to net zero emissions by 2050.

After investigating the viability of diesel vessel exhaust scrubbers, green ammonia, made by electrolyzing water with renewable electricity, was proposed as an alternative fuel source to quickly decarbonize the shipping industry. However, historically there has been great uncertainty as to how and where to invest to create the necessary infrastructure to deliver an efficient, viable fuel supply chain.

“Our results provide a fresh view how a future green ammonia supply-chain could look like to provide enough fuel for shipping,” said the study’s lead author Dr. Jasper Verschuur. “Compared to the existing supply network of shipping fuel based from oil, the future ammonia fuel supply is more regional, with large producers being those with good solar resources and close to major shipping hubs. Our results also underline that investments up to US$2 trillion are required to build new infrastructure, with a large share of this in developing countries. Here, green finance is key to support the transition to hydrogen and green ammonia production in those countries.”

“Green ammonia is the most promising fuel for decarbonization of shipping. This analysis combines a global spatial optimization of green ammonia production, with the global shipping model developed in ECI which simulates where green ammonia will be shipped to and used,” said Professor Jim Hall, Oxford Programme for Sustainable Infrastructure Systems (OPSIS) lead at the ECI.

“Shipping is one of the most challenging sectors to decarbonize because of the need for fuel with high energy density and the difficulty of coordinating different groups to produce, utilize and finance alternative (green) fuel supplies,” added René Bañares-Alcántara, Professor of Chemical Engineering in the Department of Engineering Science at the University of Oxford.

To guide investors, the team at the University of Oxford developed a modelling framework to create viable scenarios for how to establish a global green ammonia fuel supply chain. The framework combines a fuel demand model, future trade scenarios and a spatial optimisation model for green ammonia production, storage, and transport, to find the best locations to meet future demand for shipping fuel.

“The implications of this work are striking. Under the proposed model, current dependence upon oil-producing nations would be replaced by a more regionalized industry; green ammonia will be produced near the equator in countries with abundant land and high solar potential then transported to regional centers of shipping fuel demand,” Bañares-Alcántara stated.