While there is global potential to generate renewable energy at costs already competitive with fossil fuels, a means of storing and transporting this energy at a very large scale is a roadblock to large-scale investment, development and deployment. Ammonia produced from renewables can be a viable liquid fuel replacement for many current-day uses of fossil fuels, including as a shipping bunker fuel; as a diesel substitute in transportation; as a replacement fuel in power turbines; and even as a potential jet fuel. The global transportation of ammonia by pipeline and bulk carrier is already a well-developed technology.

Researchers at Monash University in Australia are proposing a roadmap to renewable ammonia being produced in the future at a scale that is significant in terms of global fossil fuel use. This, they suggest in a paper in Joule, will emerge via three overlapping technology generations:

  • Generation 1 is based on an expansion of current-day Haber-Bosch ammonia production using CO2sequestration or offsets.
  • Generation 2 moves the Haber-Bosch process to renewable sources of hydrogen.
  • Generation 3 avoids the need for the Haber-Bosch process entirely by direct electrochemical conversion of N2 to NH3. One of the attractive features of generation 3 technology is that it can be implemented at any level of scale, from kW to GW, and in a highly distributed fashion.