A thermochemical energy storage (TCES) system integrated with a concentrated solar power (CSP) plant can smoothly supply renewable electricity. In the current study, a novel system scheme based on the cogeneration of electricity, thermal energy storage, and hydrogen production has been proposed and analyzed. The system is divided into four units: a charging section, a discharging section, a power block, and a methanol steam reforming (MSR) unit. The proposed system is powered by solar energy, some part of which is utilized in the power block for electricity generation, and the remaining is stored in the charging section by a CaCO3/CaO-based TCES system. At the same time, the hydrogen is produced in the MSR unit that is powered by thermal energy supplied by the power block. Furthermore, the proposed system works in two modes: sunshine and night modes. Exergy analysis, along with sensitivity analysis based on power conditions, is performed for the whole system. The results reveal that the inlet temperature of turbines is the most influential parameter in sunshine mode. Upon increasing its value, the heat supply to the MSR unit is enhanced by 10.3%. Similarly, cycle intermediate pressure enhances the heat supply to the MSR unit by 10.4% in night mode. The exergy values recovered by the MSR unit in the sunshine and night modes are 12.19 MW and 29.64 MW, respectively. The MSR reaction is carried out at 246 °C and 1 atm with a water-to-methanol ratio of 5.6 that yields 997.7 kmol/h and 2481.5 kmol/h of H2 in sunshine and night modes, respectively.