A Photovoltaic-Thermochemical Hybrid Solar Power Generator

High penetration of photovoltaic (PV) power into the energy system could be challenged by its limited dispatchability related to fluctuations and intermittency of solar illumination. We demonstrate an integrated PV-thermochemical (PVTC) device that backs up PV output with dispatchable power generated by solar-thermal enriched fuel. The H2-rich fuel as derived from PV-thermal-driven endothermic chemical reaction enables an overall experimental solar-to-power efficiency of 43.7%, among which more than 40% is contributed by solar thermal energy. This represents a 9.2 percentage points advance over all prior solar PV-thermal power efficiencies reported to date. A modular PVTC prototype based on a triple-junction PV cell and methanol reforming reaction was demonstrated with 24 h continuous operation at a sustained power output of 27.4 W. Cost analysis indicates levelized cost of electricity (LCOE) ranges of 0.173 – 0.273 $ kWh-1 and 0.097 – 0.197 $ kWh-1 for 5 kW and 100 kW PVTC systems, respectively, which are considerably lower than that of PV-battery combination (0.578 – 0.802 $ kWh-1).