Techno-economic and environmental analysis of heat sources for steam methane reforming in microgrids

Isolated microgrids with diverse onshore natural gas resources have the potential to produce grey hydrogen. However, existing literature has not fully investigated how to support the thermal load necessary for the steam methane reforming process in such an environment. This study conducts technoeconomic and environmental analyses of an isolated microgrid comprising solar photovoltaics, wind units, battery storages, microturbines, and steam reformers that produce grey hydrogen. We formulate thermodynamic models in which the heat for steam reforming is supplied by combined heat and power, gas, electric, and hybrid boiler systems. We examine the effect of the thermal source on the optimal configuration, net present cost, and CO2 emissions. Using an isolated microgrid in East Owienat, Egypt, as a case study, we find that the levelized cost of hydrogen ranges from 2.1 to 2.8 $/kg. The combined heat and power boiler system exhibits the lowest net present cost and levelized cost of hydrogen even when the CO2 penalty cost is considered. Specifically, the net present cost of the combined heat and power boiler system is 13.6 % lower than that of the electric boiler.