Carbon Dioxide Shuttling Thermochemical Storage Using Strontium Carbonate

Global energy demands are continuously increasing while the forecast for fossil fuels is filled with uncertainty. In addition to increasing energy consumption, there are also inevitable problems associated with using fossil fuel as a main energy resource, such as climate change and atmospheric pollution.  Concentrated solar power (CSP) is one promising method of converting clean solar thermal energy into electricity which avoids such environmental problems.  Thermal energy storage (TES) in conjunction with CSP, can avoid these environmental problems and increase the utilization of solar energy by enabling plant operators to generate electricity beyond normal on-sun hours. Thermochemical energy storage is an emerging type of TES system based on a reversible reaction. Thermochemical energy storage of on-sun thermal energy is achieved when a reactive system absorbs thermal energy and proceeds with a reversible chemical reaction. In a time of off-sun power demand, the reverse reaction is then initiated and energy is released, thus recovering thermal energy for use in a power cycle.  One such reactive system is the reversible carbonation/decomposition of SrO/SrCO₃, which occurs ca. 1200°C.  Such high quality heat is suitable for high efficiency, combined cycle power generation, which has the potential to translate into more competitive solar electricity prices.

Over many cycles, SrO/SrCO₃ sinters and becomes less reactive. This presentation will focus on the use of different dopants to synthesize a sintering resistant compound. By reducing sintering, the reversible reaction will yield higher efficiency and be more reactive over a longer period of time.