United States Hydrogen Hubs and Required NOx Emission Regulations

U.S. Department of Energy announced seven regional hydrogen hubs in the United States in October 2023. Together with smaller scale local hydrogen demonstration projects, the replacement of fossil fuels with hydrogen and other low carbon fuels has been considered a key pathway to decarbonize the existing fossil fuel system by the federal and local government. In the past few decades, the combustion systems using fossil fuel have been optimized towards the fuel flexibility, high efficiency, and low NOx emissions direction. One of the major concerns is the impact of hydrogen on NOx emissions. Does hydrogen have a positive or negative impact on NOx emissions? This presentation introduces the NOx emission regulation background in the U.S., the mechanism of NOx formation and hydrogen impact on NOx emissions in combustion applications.