Exploring the potential of an adsorption-based compressed CO₂ energy storage system improving the operational flexibility of thermal power units: Full operating conditions performance and techno-economic assessment

With the installed capacity of renewable energy exceeding that of thermal power units in China, enhancing the flexible peaking capability of thermal power units has been the critical need for constructing modern electric power system. Orientation to the issue, this paper proposes an integrated system of thermal power units coupled with a novel adsorption-based compressed CO₂ energy storage system and analyzes the performance under design and off-design conditions. The results show that AB-CCES system significantly widen the load regulation range by extracting steam and heating condensate. RTE, EXE, ESD and CYE of AB-CCES system are 87.62 %, 71.87 %, 6.17 kWh/m³ and 82.26 %, respectively. Desorption temperature reaches 195.08 °C. Coal saving quality are 10.33 tons per day. Thermodynamic performance of AB-CCES system is more strongly affected by different THA conditions than by mass flow rate. Thermodynamic performance of the integrated system is better than that of the original CHP unit, except for mass flow ratios exceeding 1.12 and less than 60 % THA conditions. The minimum load output ratio of the integrated system is 17.12 % Pe. DPP, IRR and NPV of the integrated system are 7.84 years, 20.58 % and 163.17 million ¥, under rated operating conditions.