The Calcium-Looping (CaCO3/CaO) process for thermochemical energy storage in Concentrating Solar Power plants (original) (raw)

2019, Renewable and Sustainable Energy Reviews

Energy storage based on thermochemical systems is gaining momentum as potential alternative to molten salts in Concentrating Solar Power (CSP) plants. Several systems have been proposed in the last years, mainly based on hydroxides, organic compounds, carbonates, metal redox, hydrides, ammonia or sulfur. This work is a detailed review about the promising integration of a CaCO3/CaO based system, the so-called Calcium-Looping (CaL) process, in CSP plants with tower technology. The CaL process relies on low cost, widely available and non-toxic natural materials (such as limestone or dolomite), which are necessary conditions for the commercial expansion of any energy storage technology at large scale. A comprehensive analysis of the advantages of this process and challenges to be faced for it to reach a commercial scale is carried out. The review includes a deep overview of reaction mechanisms and process integration schemes proposed in the recent literature. In addition, the technological maturity and potential of the process is assessed. The direction towards which future works should be headed is discussed. CO2 (g) CALCINER CaCO3 (s) CaO (s) + CO2 (g) ΔHr 0 = +178 kJ/mol CaO (s) HEAT EXCHANGER NETWORK CO2 COMP CO2 storage CaCO3/CaO storage CaO storage CARBONATOR CaO (s) + CO2 (g) CaCO3 (s) ΔHr 0 =-178 kJ/mol HEAT EXCHANGER NETWORK CO2 TUR Q CSP CO2 (g) CaO (s) POWER CYCLE