## 1 Introduction
P2G methanation reaction uses electrolytic water to produce hydrogen and produces methane with CO2 under the action of a catalyst, so the purchase of carbon is also an important part of P2G operation cost. At the same time, although the use of P2G and thermoelectric decoupling can effectively improve wind power consumption, the carbon emissions of thermal power units still need to be solved. Carbon capture and storage (CCS), as a low-carbon technology to cope with climate change, has great development potential and has been highly valued by countries around the world. The installation of carbon capture equipment in thermal power units can capture about 90% of CO2 to store and utilize it. With the full use of existing units, it can realize low-carbon power generation, which to some extent reduces the grounding cost of existing fossil fuel units and the large investment in renewable energy power generation. [PERSON] et al. [18] analyzes CCS cost reduction and its macroeconomic effects and shows that CCS can be economically feasible in the long term. A highly accurate surrogate model of CCS had been built for overall power consumption and separation responses by [PERSON] et al. [19]. [PERSON] et al. [20] discussed the modeling and analysis of the carbon capture technology in emission-constrained environment. The low-carbon economic dispatch considering carbon capture power plant is solved in a multi-objective optimization framework by [PERSON] et al. [21]. [PERSON] et al. [22] described a multi-period optimization model for carbon capture power plant. With the increasing attention to carbon emission, carbon dioxide removal technologies have been developed rapidly. [PERSON] et al. [23] presented an advanced sub-ambient membrane process that improved CO2/N2 selectivity at low temperatures and reduced the cost of carbon capture. A solvent storage model had been proposed to improve the power plant's ability to reduce power output while operating the CCS system, improving electricity sales revenue by [PERSON] et al. [24]. [PERSON] et al. [25] investigated the technical and economic feasibility of achieving zero and negative carbon dioxide emissions in pulverized coal and natural gas combined cycle power plants using conventional amine scrubbing using 30 wt% water ethanolamine. A mixture of ionic liquid and monoethanolamine (MEA) was proposed as a solvent choice with promising prospects for carbon dioxide removal technology by [PERSON] et al. [26]. [PERSON] et al. [27] proved that the capture level reduction mode is more economical than the traditional mode when applied to natural gas power plants, reducing the economic disadvantage of carbon capture power plants. [PERSON] et al. [28] proved that after adding sulfolane or imidazole to the second-generation flue gas amine washing solvent, the circulation capacity of carbon dioxide increases, and the effect of capturing carbon dioxide increases. [PERSON] et al. [29] proposed that the coupling of electrocatalytic technology and renewable energy is an important development direction in the future, which can improve the adsorption capacity of metal organic frameworks for carbon dioxide. [PERSON] et al. [30] proved that pH change in mineral carbonation results in a carbon dioxide capture efficiency of 40-50%. [PERSON] et al. [31] designed a dehydration compression device that captures carbon dioxide after combustion, reducing the total energy consumption in CCS. According to the above analysis, in response to the dual carbon goal, this paper introduces a ladder-type carbon trading mechanism from the perspective of low carbon, uses P2G heat recovery to realize the electricity-gas-heat network coupling and uses the CO\({}_{2}\) captured by CCS directly for methane production. At the same time, P2G and a heat storage tank can achieve thermoelectric decoupling and wind power consumption through collaborative operation, which realizes the low-carbon operation of the system and reduces CO\({}_{2}\) emissions and wind abandonment rate.