Ammonia as a Carbon-Free Energy Carrier: NH3 Cracking to H2

In the energy transition from fossil fuels to renewables, hydrogen is a realistic alternative to achieving the decarbonization target. However, its chemical and physical properties make its storage and transport expensive. To ensure the cost-effective H2 usage as an energy vector, other chemicals are getting attention as H2 carriers. Among them, ammonia is the most promising candidate. The value chain of NH3 as a H2 carrier, considering the long-distance ship transport, includes NH3 synthesis and storage at the loading terminal, NH3 storage at the unloading terminal, and its cracking to release H2. NH3 synthesis and cracking are the cost drivers of the value chain. Also, the NH3 cracking at large scale is not a mature technology, and a significant effort has to be made in intensifying the process as much as possible. In this respect, this work reviews the available technologies for NH3 cracking, critically analyzing them in view of the scale up to the industrial level.