Ammonia for marine propulsion

The chapter deals with the challenges and issues related to the possible penetration of “green ammonia” as breakthrough solution to decarbonize the marine sector. After a brief analysis related to the radical change/transformation of this sector, driven by recent national/international pollutants' emission regulations and socio-politic constraints, the role of ammonia as a no-carbon fuel is deeply discussed in relation to ammonia chemical/physical properties. In this perspective, ammonia constitutes an energy storage solution that can be produced through existing synthesis methods and storage solutions, with a large potential to enter the market relatively quickly. Nonetheless, the paradigmatic change induced by the utilization of ammonia as alternative to conventional fossil fuels mandatorily steps through the definition and optimization of new technologies and novel engines' architecture. This aspect is analyzed through a dedicated scientific literature survey, starting from ammonia State-of-the-Art in marine engines, progresses and developments, up to the identification of new solutions.