Massive green ammonia production key to decarbonizing shipping industry – study

Iron ore shipment. (Reference image by henkerik, Flickr.)

A study by researchers at the University of Oxford found that green ammonia could be used to fulfill the fuel demands of over 60% of global shipping by targeting just the top 10 regional fuel ports.

By looking at the production costs of ammonia which are similar to very low sulphur fuels, the team concluded that the fuel could be a viable option to help decarbonize international shipping by 2050. 

Ammonia (NH3) is easy to store as a liquid and is able to deliver about half the energy density of common fossil fuels.

Traditionally, it has been produced by stripping hydrogen from natural gas using steam and combining the H2 with nitrogen from the air at high pressure and temperatures. This process releases close to two tonnes of CO2 into the atmosphere for every tonne of usable ammonia.

However, the compound can now be made with hydrogen split from water with electricity sourced from renewable sources and then combining it with nitrogen.

According to the Oxford study, $2 trillion will be needed to transition to a green ammonia fuel supply chain by 2050, primarily to finance supply infrastructure.

The paper, published in the journal Environmental Research: Infrastructure and Sustainability, shows that the greatest investment need is in Australia, to supply the Asian markets, with large production clusters also predicted in Chile to supply South America, California to supply the Western US, North-West Africa to meet European demand, and the southern Arabian Peninsula to meet local demand and parts of South Asia.

The research notes that 90% of the world’s physical goods trade is transported by ships which burn heavy fuel oil and emit toxic pollutants. This accounts for nearly 3% of the global greenhouse gas emissions. As a result of this, the International Maritime Organization committed to reach net-zero emissions by 2050. 

After investigating the viability of diesel vessel exhaust scrubbers, green ammonia was proposed as an alternative fuel source to quickly decarbonize the shipping industry. Yet, 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. 

“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,” René Bañares-Alcántara, co-author of the study, said in a media statement.

To guide investors, Bañares-Alcántara and his colleagues 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 optimization 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 and then transported to regional centres of shipping fuel demand,” Bañares-Alcántara continues said.