The urgent requirement to decarbonise the transportation sector has accelerated efforts to aid the transition from internal combustion engines (ICEs) running on conventional fuels to more sustainable alternatives. Although electrification offers a viable long-term solution, its current limitations necessitate complementary approaches that can be immediately implemented. Green ammonia has attracted considerable attention as a carbon-free fuel owing to its benefits of high energy density, ease of storage and transport. However, significant challenges such as low laminar flame speed, high autoignition temperature, and safety concerns during handling and combustion hinders its widespread utilisation. In addition, the environmental viability of the process is diminished when conventional ammonia is produced by the fossil fuel dependent Haber-Bosch (H-B) Process. Two primary green production pathways have gained attention to address this: integration of renewable hydrogen into the existing H-B process and electrochemical ammonia synthesis, both of which require substantial technological advancement and investment. The maritime sector, in particular, presents a significant potential for retrofitting existing ICEs to utilize ammonia, leveraging existing infrastructure while minimizing emissions. Nevertheless, this transition demands innovative combustion strategies and engine modifications to enhance ammonia’s ignition and combustion characteristics. Overall, the successful deployment of green ammonia as a sustainable fuel hinges on concurrent advancements in production methods and combustion technologies, supported by continued research and policy-driven investment.
Dhar et al. (Fri,) studied this question.