Limitations of Ammonia as a Hydrogen Energy Carrier for the Transportation Sector

Annual global carbon dioxide (CO2) emissions reached 34. 2 gigatonnes (Gt) in 2019 as a result of extensive and unrestricted use of fossil fuels to fulfill ∼80% of society’s energy needs at the current level of ∼585 exajoules (EJ) /year. 1, 2 Transportation that provides mobility to and freight is responsible for approximately 25% of the overall CO2 emission. 3, 4 Considering the current rate of population growth and associated increases in energy consumption, it has been projected that the corresponding global energy demand will be increased by at least 50% before 2050. 1, 2, 5 To meet such needs while minimizing the environmental impacts by curtailing anthropogenic CO2 emissions, large-scale deployment of low-carbon renewable energy (RE) is necessary. 6−8 Despite a moderate increase in the overall of RE in the current energy landscape, recent studies indeed indicated that a full transition to 100% RE is attainable within the next 3 decades or so with a cost-efficient vision of deep electrification of heat and transportation sectors around the globe. 9−11 Thus, this energy transition is no longer a matter of technical feasibility or economic viability, but political will.