Green Ammonia: An Alternative Sustainable Energy Source for Clean Combustion

Continuous fossil fuel extraction and its use, environmental pollution, and future energy security are key alarming concerns for the modern civilization. Most of the countries at the beginning of this century witnessed huge diesel-powered vehicular registration. Diesel engine and its noxious nitrogen oxides (NOx) and soot emissions caused a shock to the diesel engine market and its existence in dispute. That is why transportation industries are in strict focus on carbon neutrality by developing alternative fuels. Despite NOx and soot emissions reduction, decarburization of automotive and power generation industries is mandatory to tackle the greenhouse gas (GHG) emissions target. The absence of carbon-containing compounds in ammonia (NH3) makes it a promissing carbon-free fuel to achieve the decarburization of power generation industries. Ammonia possesses major advantages like, easy liquefaction, storage at low pressure and ambient temperature or low temperature and ambient pressure, less expensive storage systems, and high energy density than natural gas (NG) or hydrogen (H2). Ammonia can efficiently be combusted with diesel or other low auto-ignition fuels for the significant reduction of carbon-based emissions. This paper summarizes the challenges, present scope, and future potentials of green ammonia as a carbon-free fuel. In this paper, the production process of NH3, its characteristics as a fuel, potential role as a H2 carrier, combustion behavior, and overall technological advancement have been discussed.