Optimization Strategies of Photovoltaics-Powered Green Hydrogen Production

Green hydrogen production powered by photovoltaics provides a clean solution for energy conversion and storage. The key parameter of photovoltaic electrolysis (PV-EC) system is the solar-to-hydrogen (STH) efficiency. Previous studies have been mostly focused on improving the efficiency of each system individually using multi-junction PV materials, catalysts and electrolytes. However, the coupling between photovoltaic and electrochemical devices is still elusive to achieve high STH efficiency in a system level. In our study, the optimization strategies of PV-EC systems are demonstrated to approach thermodynamic limit (26.6%) for green hydrogen production. First, we list three design parameters for modeling, namely number of PV, number of EC and the area ratio between PV and EC. Then we model the crystalline silicon PV coupled with a real EC system. The STH efficiency varies under different PV and EC combinations. The STH efficiency map clearly defines three regions indicating the engineering space for PV-EC coupling, Tafel slope and area ratio. The optimization strategies presented in this study can lead to further advancements in coupled PV-EC systems with well-controlled performance for different conditions.