Offshore green ammonia synthesis

The global potential for renewable energy production far exceeds global energy demand. However, the accessibility of renewable energy is constrained by existing land use, the need to preserve protected areas and the costs associated with transporting energy over large distances. As a consequence, finite renewable energy capacity must be carefully matched to appropriate end uses. In this Perspective, we advocate the production of green ammonia on the ocean to address this policy challenge: local renewables should be used to generate electricity with high efficiency, whereas comparatively low-efficiency chemical energy storage in the form of ammonia should occur further away from energy consumers and be transported at relatively low costs. We describe the synthesis processes to be adopted, the techno-economic basis for this resource allocation, and the technical developments required that can enable this energy system to be established. Green ammonia will play an important function in decarbonized energy systems but its production places a high burden on limited renewable resources in land-constrained countries. Here we propose the offshore production of green ammonia, which can increase energy security without land competition.