Scholarlink

With onus to decarbonise, the maritime sector is transitioning away from fossil fuels. Ammonia (NH3) is being increasingly viewed as a ‘greener’ alternative for which the first commercial engines became operational in 2024; however, research is still ongoing to solve bottlenecks during combustion (unburned NH3 and N2O emissions). The combustion or ‘tank-to-wake’ emissions notwithstanding, the mitigation of environmental impacts from the production or ‘well-to-tank’ phase needs to be addressed. In line with the conference topic of ‘alternative fuels and decarbonisation’, this study aimed to understand the environmental hotspots in the ammonia value chain using a life cycle assessment (LCA). A prospective LCA was carried out to evaluate the impacts of NH3 production pathways, some defined by IMO’s Marine Environment Protection Committee (MEPC 81) from a well-to-tank perspective, both as they exist today and their evolution over the next 15 years. The prospective LCA compared the environmental impacts of NH3 from steam methane reforming (SMR), with and without carbon capture and storage (CCS), electrolysis with electricity from the grid and from renewable sources (e-ammonia). Parameters for the sensitivity analysis are chosen based on IMO and EU policies that are intended to drive NH3 production. Our analysis shows that producing NH3 using green H2 in the next decade reduces environmental impacts compared to the status quo, but its scalability depends on energy infrastructure and the availability of electrolysers. We identified that the carbon footprint of e-ammonia using grid electricity is highest in China, followed by Australia (30% lower than China), and the USA (44% lower than China). With influx of renewable energy, the carbon footprint declined in 2040, particularly in the USA and Australia, while China’s slower decarbonization keeps its impacts high through 2040. We also observed Iridium for Proton-exchange membrane (PEM) electrolysers pose challenges for future NH3 production due to crustal scarcity and geopolitical constraints.

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

A Regionalised Life Cycle Perspective of Ammonia Production as a Maritime Fuel

  • 会议论文

  • 发表日期：

    2025年

查看全文
  • Rahul Ravi,
  • Kristine Marie Embretsen,
  • Fasil Ayelegn Tassew,
  • Oleksii Ivashenko

摘要

With onus to decarbonise, the maritime sector is transitioning away from fossil fuels. Ammonia (NH3) is being increasingly viewed as a ‘greener’ alternative for which the first commercial engines became operational in 2024; however, research is still ongoing to solve bottlenecks during combustion (unburned NH3 and N2O emissions). The combustion or ‘tank-to-wake’ emissions notwithstanding, the mitigation of environmental impacts from the production or ‘well-to-tank’ phase needs to be addressed. In line with the conference topic of ‘alternative fuels and decarbonisation’, this study aimed to understand the environmental hotspots in the ammonia value chain using a life cycle assessment (LCA). A prospective LCA was carried out to evaluate the impacts of NH3 production pathways, some defined by IMO’s Marine Environment Protection Committee (MEPC 81) from a well-to-tank perspective, both as they exist today and their evolution over the next 15 years. The prospective LCA compared the environmental impacts of NH3 from steam methane reforming (SMR), with and without carbon capture and storage (CCS), electrolysis with electricity from the grid and from renewable sources (e-ammonia). Parameters for the sensitivity analysis are chosen based on IMO and EU policies that are intended to drive NH3 production. Our analysis shows that producing NH3 using green H2 in the next decade reduces environmental impacts compared to the status quo, but its scalability depends on energy infrastructure and the availability of electrolysers. We identified that the carbon footprint of e-ammonia using grid electricity is highest in China, followed by Australia (30% lower than China), and the USA (44% lower than China). With influx of renewable energy, the carbon footprint declined in 2040, particularly in the USA and Australia, while China’s slower decarbonization keeps its impacts high through 2040. We also observed Iridium for Proton-exchange membrane (PEM) electrolysers pose challenges for future NH3 production due to crustal scarcity and geopolitical constraints.