Assessment of Ammonia as an Energy Carrier from the Perspective of Carbon and Nitrogen Footprints

Ammonia has been proposed as a promising energy carrier and is expected to play a resilient and sustainable role in future energy scenario. Energy systems critically impact biogeological carbon and nitrogen cycles. Thus, carbon and nitrogen footprints are two important indicators of sustainability for energy systems. In the present study, we explored the optimal supply pathway and identified impact hotspots by investigating the carbon footprint associated with greenhouse gas emissions and the nitrogen footprint associated with reactive nitrogen emissions from the ammonia energy system. Four scenarios (Japan to Japan, JP-JP; Australia to Japan, AU-JP; Chile to Japan, CL-JP; Saudi Arabia to Japan, SA-JP) were modeled based on international relations and energy distribution between these countries. Compared with Japan electricity mix, it is a win-win situation under scenario JP-JP from the perspective of carbon and nitrogen footprints while trade-offs were identified under scenarios AU-JP and CL-JP. SA-JP pe...