A critical evaluation of potential routes of solar hydrogen production for sustainable development

This paper provides a comprehensive review on the various techniques and routes of solar hydrogen production. The solar energy options considered are thermal energy, electrical energy, photonic energy, and hybrid options. The hybrid option includes thermal and electrical, electrical and photonic, biochemical and thermal, and biochemical and photonic energies. Some relevant literature review with their key findings, conclusions, and suggestions is presented. Various methods of solar energy-based hydrogen production are explained and briefly discussed. The technologies available for realizing these methods are also presented. Some recent advances in solar hydrogen generation is also presented in which some novel techniques are discussed. Some plant configurations are also discussed and compared to consider the factors which influence the cost of hydrogen. This review article also aims to comparatively assess and evaluate the several routes of producing hydrogen using solar energy. The comparative evaluation is performed using two sets of criteria. Criteria set 1 consists of environmental impact and cost of hydrogen production. Criteria set 2 comprises energy and exergy efficiencies, sustainability indices and hydrogen production rates. High-temperature energy methods show much better efficiencies and hydrogen yield while at the same time are more environmentally harmful. Photonic and biochemical energy routes are more environmentally friendly and sustainable, but have low efficiencies. (C) 2020 Elsevier Ltd. All rights reserved.