Solar radiation is highly intermittent and its use for demand-sensitive electricity generation requires energy storage. Storing large amounts of solar-produced electricity is challenging and has been a highly sought after goal. High-temperature solar thermal energy storage can be deployed as an alternative enabling technology for matching solar radiation availability and electricity demand.

This project aims at developing a novel high-temperature thermochemical energy storage syst em for dispatchable and efficient concentrating solar power generation via combined power cycles. The proposed approach is based on the manganese-oxide redox cycle in a system involving two fluidised-bed reactors (Fig. 1), one for solar-driven high-temperature endothermic reduction and one for non-solar lower-temperature exothermic oxidation. We will develop stable and durable redox materials promising high reaction rates, and development of a solar reduction reactor prototype promising high efficiency. The solar reactor is a novel beam-up concept that allows for suppression of convective heat losses from a down-facing receiver cavity, effective and well-controlled fluidisation of the redox material due to a symmetric vertical orientation, and high optical efficiency due to the symmetric field layout around the receiver.

The proposed technology allows for higher operating temperatures, and thus higher efficiencies of the power cycle, compared to non-thermochemical storage systems. It has the potential for efficient and fast-response high-energy density storage in the solid oxide material.