Energy and exergy analysis of the integration of concentrated solar power with calcium looping for power production and thermochemical energy storage

Concentrated solar power (CSP) cannot stand as a sustainable solution for power production without daily interruption unless solar energy is stored for the night hours. Solar intermittency and equally often non-dispatchability can be constrained by the use of energy storage. Thermochemical energy storage (TCES) based on the calcium looping (CaL) process is a distinctive and highly promising technology as it stores energy in the form of chemical bonding through the calcination reaction (CaCO3 -> CaO+CO2). Solar energy is required to accomplish the endothermic calcination reaction, while it is released as thermal energy during the exothermic carbonation reaction (CaO+CO2 -> CaCO3). This paper presents an energy and exergy analysis of the integration of a CSP-CaL plant, based on simulation results performed in AspenPlus (TM). The process flow diagram includes an indirect solar integration, while power production occurs uninterruptedly through the integration of CO2 based Brayton cycle as well as Steam Rankine cycle (SR) of various configurations. Global energy efficiencies of 28.6-31.5% can be achieved under several operating policies. The exergy analysis focuses on examining the critical irreversibilities of the system, under the variation of key process parameters values such as CO2 inlet temperature to calciner, carbonation pressure and CaO storage temperature. (C) 2020 Elsevier Ltd. All rights reserved.