Dispatchable power supply from beam down solar point concentrator coupled to thermal energy storage and a Stirling engine

Abstract

A high concentration high-temperature beam down solar point concentrator is proposed, coupled to thermal energy storage and a Stirling engine to deliver fully dispatchable electricity over 24 h. Full 24 h operation at nominal power is permitted during the month of maximum solar energy collection while in the month of minimum solar energy collection, the full power production is limited to 17.06 h. The monthly average capacity factors oscillate between 71 and 100%, with an average of 87.5%. Thanks to an electric heater for the heat storage fluid, the system can accept excess electricity from the grid to compensate for the loss of the solar energy collected every other month versus the solar energy collected during the best summer month, to operate at rated power 24 h a day in every day of the year. In this case, the capacity factor can reach 100% every month. By further increasing the size of the thermal energy storage and the power of the engine, the electric thermal energy storage capability of the system can be enhanced, increasing the amount of electricity otherwise wasted that could be collected from the grid to be then returned when needed.