###### Abstract
As previously mentioned, recovering LNG cold resources to improve the LAES system's performance has proved to be an effective solution for the development of LAES technologies. In many countries, NG is one of the main fuels for peaking power plants and, therefore, utilizing only LNG cold energy results in a waste of the NG work capacity. A prospective method for improving the power output and power delivery flexibility of a stand-alone LAES system is to integrate a natural gas power plant (NGPP) into the LAES. The internal cold energy recovery can liquefy and, thus, capture the CO\({}_{2}\) generated in the NGPP, ensuring low CO\({}_{2}\) emission operation. From a thermodynamic and economic point of view, the installation of an NGPP and cryogenic CO\({}_{2}\) capture and storage (CCS) in a typical LAES is complex and worth investigating. Economic analysis of the LAES system has drawn more and more attention in recent years. The high-grade heat from nuclear [16], photovoltaic power plants [17], and biomethane [18] were introduced into LAES to improve their economic characteristics. Ref. [19] provided a net present value (NPV) assessment of an LAES system in the UK. The optimization results revealed that the shortest payback period for a 200 MW LAES system was 5.6 years. Ref. [20] considered an LAES system based on the Kapitza liquefaction cycle. The minimum payback period was 2.99 years through the integration of a thermoelectric generator. Ref. [21] proposed a tri-generation LAES system that supplied electricity, heat, and cold energy. The sensitivity analysis indicated that the profitability of the system was susceptible to peak electricity prices. Ref. [22] developed a real-time optimal dispatching algorithm to optimally control the LAES system by weekly-ahead electricity market price forecasting. Using the electricity market price from Ontario, the LAES system was proven to have positive revenues with an RTE of 60%. Ref. [23] proposed a tri-generation LAESsystem, which could provide 2.0 MW power in transition seasons, 1.7 MW heating in winter, and 2.4 MW cooling in summer. The authors underlined the competitive economic characteristics of LAES compared to other EES technologies, particularly the specific investment and the levelized cost of electricity (LCOE). Ref. [24] found that the LCOE for an LAES system equipped with an NG combustion process could be reduced to 161 EUR\(\cdot\)MWh\({}^{-1}\), which was lower than that of an LAES system with waste heat recovery (171 EUR\(\cdot\)MWh\({}^{-1}\)). The above studies have analyzed LAES systems in regard to a wide range of reported economic characteristics and underlined the potential for commercial development and the application of LAES technologies. However, little literature has been found on the economic study of an LAES-NGPP-CCS system. Here, an LAES system enhanced with an NGPP is proposed for both electrical energy storage and power peak shaving. The system uses inexpensive electricity to produce and store LA. When electricity prices are high, gasified LA is split into two parts in a specified ratio, a part of them is expanded directly in air turbines (ATs) and the other combusts with NG and, then, drives a flue gas turbine (GT). A CCS unit is incorporated into the proposed plant, which allows the proposed system to overcome the operational limitations imposed by stricter CO\({}_{2}\) emission standards. The research discusses whether this integrated design is theoretically feasible for future adoption. The objective of this study is to assess the thermodynamic sensitivity and economic profitability of the proposed system with different charging pressures, air expansion stages, and on-peak and off-peak electricity prices. In Section 2, the system configuration and operation mechanism are described. In Section 3, the initial conditions, assumptions, and mathematical models are given. In Section 4, the results of the thermodynamic and economic evaluation are presented and discussed. In Section 5, the main findings are summarized.