Efficient solar power generation combining photovoltaics and mid-/low-temperature methanol thermochemistry

Highlights: •A PVT system integrating PV and thermochemistry is proposed, for the first time. •High efficiency, energy storage ability and temperature insensitivity are achieved. •Net solar-electric efficiency of 43% and overall efficiency of 55% are obtained. •Solar energy storage via syngas enables stable power supply all day long. -- Abstract: A hybrid solar power generation system integrating a solar photovoltaic (PV) module and a solar thermochemical module is proposed based on methanol thermochemistry. Sunlight is concentrated by trough mirror collectors and partially converted to electricity by PV cells overlain on the surface of a solar thermochemical reactor. An endothermic chemical process of methanol (e.g., decomposition) within the reactor then absorbs the "waste heat" of the PV cells and simultaneously cools the cells. During this process, the low-level thermal energy from the sunlight is upgraded to high-level chemical energy in syngas, which is stored and burned to generate electricity when necessary. Analysis indicates that the theoretical net solar-electric efficiency of the hybrid system could be as high as 45% and relatively insensitive to operation temperature and pressure. Additionally, the system exhibit a good potential in solar energy storage, and capable of providing stable electricity supply around the clock. The PV–thermochemical hybrid system might suggest a promising approach for efficient and stable power generation from solar energy.