Hydrogen Production

This chapter describes existing and potential future hydrogen production methods and investigates a variety of alternative hydrogen production methods via the utilization of renewable and nonrenewable energy resources. In addition, these alternative hydrogen production methods are comparatively assessed by taking their emissions, hydrogen production cost, and energy and exergy efficiencies. Furthermore, the relationship between environmentally harmful emissions and their economic impact is evaluated based on a concept called the social cost of carbon (SCC). Electrical, thermal, biochemical, photonic, electrothermal, photoelectric, and photobiochemical are the principal energy resources evaluated in this chapter. The comparative assessment outcomes of this chapter indicate that photonic energy is more environmentally benign compared to other principal energy resources evaluated in this chapter. In this chapter, the selected photonic energy-based hydrogen production methods are photocatalysis, photoelectrochemical (PEC) method, and artificial photosynthesis. Among other selected hydrogen production methods, thermochemical water dissociation and hybrid thermochemical (such as Cu–Cl, S9I, and Mg–Cl) cycles are environmentally benign with less emissions compared to other selected methods too. When it comes to hydrogen production cost and energy and exergy efficiencies, PEC and photovoltaic (PV) electrolysis-based hydrogen production have the lowest performance. For that reason, it is concluded that in order to make these environmentally very benign solar-based hydrogen production options the preferred components of future energy systems, their energy and exergy efficiencies should be enhanced by using novel materials and integrated systems. With the introduction of more advanced systems and materials and the increase in efficiencies, solar-based hydrogen production methods are expected to become more cost competitive, reliable, clean, and sustainable. Due to their highly developed technologies and mostly already available infrastructures, fossil fuel reforming and biomass gasification-based hydrogen production have the highest energy and exergy efficiencies among the selected options. Overall, the results of the comparative assessment are presented by average rankings, which state that hybrid thermochemical cycles are predominantly favorable hydrogen production alternatives with their relatively low emissions and production costs and high efficiencies.