Rational Integration of Photovoltaics for Solar Hydrogen Generation

The development of commercially viable solar hydrogen generators needs to be accelerated to meet the needs of the emerging global hydrogen economy. Many different hydrogen generators have been demonstrated on a lab scale, employing semiconductor photovoltaic components integrated into the system in a variety of ways: as solar cells, photoelectrodes, and photoelectrochemical cells. Despite this, the effect of system configuration on performance has not yet been independently considered. In this work, we demonstrate that the way in which the photovoltaic components are integrated into the system is critical to maximize the solar-to-hydrogen conversion efficiency. We introduce a new framework, based on simple equivalent circuit models, to show that decoupling the PV components from the electrochemical cell by employing power management can significantly increase the system efficiency. Decoupled systems can also take advantage of existing solar cell technologies and the maturity of the silicon PV industry to rapidly advance solar hydrogen generation.