Net Zero-Carbon Emission: Assessing the Role of Ammonia

Considering the extent of combustion in energy conversion devices, every pathway to sustainable energy generation foresees a big role for carbon-free fuels like ammonia and hydrogen. However, while hydrogen is a high-performance fuel with improved environmental benefits, its uses are mostly limited to fuel cells. This is due to the complexities involved in handling, storing, and transporting hydrogen. Accordingly, ammonia, an efficient hydrogen carrier, promises to be an excellent alternative owing to its relative ease in production, storage, transportation, and high hydrogen density. However, low burning velocity and high NOx production in ammonia combustion propose challenges to developing dedicated energy conversion devices solely based on ammonia. This chapter will discuss, in detail, the recent research on ammonia combustion and its qualitative and quantitative comparison against hydrogen and conventional fuels. Moreover, a discussion on how ammonia and hydrogen can fit into the current technology space will be presented. The reader should note that it is out of scope to discuss all the combustion-oriented devices such as engines, turbines, and others; therefore, the article will mostly focus on the combustion process relevant to gas turbines. Overall, the lessons we will learn from assessing the combustion of ammonia and hydrogen are the foundational building blocks of how energy space will shape in the future.