Technological Pathways to Produce Compressed and Highly Pure Hydrogen from Solar Power

Hydrogen (H$_2$) produced from renewables will have a growing impact on the global energy dynamics towards sustainable and carbon-neutral standards. The share of green H$_2$ is still too low to meet the net-zero target, while the demand for high-quality hydrogen continues to rise. These factors amplify the need for economically viable H$_2$ generation technologies. The present article aims at evaluating the existing technologies for high-quality H$_2$ production based on solar energy. Technologies such as water electrolysis, photoelectrochemical and solar thermochemical water splitting, liquid metal reactors and plasma conversion utilize solar power directly or indirectly (as carbon-neutral electrons) and are reviewed from the perspective of their current development level, technical limitations and future potential.