A technoeconomic analysis on solar hydrogen production was recently published in Energy. Environ. Sci. by Shaner, et al. (Energy. Environ. Sci., 2016, Advance Article). The levelized cost of hydrogen was compared between photovoltaic-electrolyzers (PV-E), photoelectrochemical cells (PECs), and fossil fuel derived hydrogen using steam methane reforming (SMR).
This paper highlights the strengths of PEC systems and outlines the challenges which must be met in order for the technology to become viable. One way to make solar hydrogen production competitive with SMR is to tax the carbon dioxide that is produced. They estimate that for the current PEC technology to achieve hydrogen price parity with SMR, a carbon tax of $1000/ton C02 is required. If a solar concentrator PEC is used, the estimated tax decreases to $800/ton CO2.