9. Ammonia for Decarbonized Maritime Transportation

Carbon emissions are one of the important topics in maritime transportation recently since International Maritime Organization (IMO) implemented stricter regulations. IMO announced Initial Greenhouse Gas (GHG) Strategy in 2018 for decarbonization of maritime transportation. International shipping consumed 300 million tons of high carbon content fossil fuels annually and it is increasing year by year. Maritime transportation constitutes 3.1% of the total global CO₂ emissions which depends on the usage of high carbon content fossil fuels. The Initial GHG Strategy aims to reach zero-carbon shipping in the future. One way to achieve this aim is the usage of alternative fuels with zero-carbon content. Ammonia is one of the alternative fuels that can be either used for fuel cells on ships and at marine diesel engines. Ammonia has a carbon-free and sulfur-free structure and it can be combusted by the dual-fuel combustion concept at marine diesel engines as same as other alternative marine fuels. In this chapter, a review study is conducted on ammonia to show its importance for decarbonized maritime transportation. The outcomes of the chapter reveal that although there are some barriers to ammonia as a marine fuel, the existing experience of the maritime industry, supply chains and infrastructures of fertilizer industry, low modification requirement on engines, and achievement of significantly lower CO₂ and soot emissions, and almost zero SO_X emissions will facilitate the use of ammonia, and it can be one of the options for full decarbonized maritime transportation by 2050.