This study focuses on photophysical/photochemical technologies for converting solar energy and water to hydrogen, namely photovoltaic + electrolysis (PV+E), photoelectrochemical (PEC) and photocatalytic (PC) water splitting. There are other promising solar hydrogen production pathways, such as those based on thermal or biological processes for water splitting or by utilizing biomass as a feedstock. While these routes are outside the scope of the present work, the described methodologies can also be applied to them.