Objective To explore the strategic positioning and mechanism of natural gas in the process of building a new energy system that takes into account safety, economy and environmental protection in China.

Method Firstly, a three-dimensional evaluation framework of "safety-economy-environmental protection" was constructed to analyze the equilibrium characteristics of natural gas. Secondly, combined with the history of energy development and the comparison of domestic and foreign transformation paths, the necessity of natural gas as a balanced energy was demonstrated. Thirdly, the unbalanced competition and regime change diachronic (UCRCD) model was used to quantify the synergistic effect of natural gas and renewable energy. Finally, the internal mechanism of natural gas playing a balanced role was analyzed from the three levels of product chain, industrial chain and value chain.

Result Natural gas has become the most balanced energy category because of its excellent comprehensive performance, and is positioned as "balanced energy " in the new energy system. Its core role is embodied in "replacing coal, stabilizing electricity, incubating hydrogen, and reducing carbon". Firstly, at the product chain level, it systematically replaces coal. Secondly, at the industrial chain level, it is strongly coordinated with renewable energy to make up for intermittent shortcomings and improve system stability. Thirdly, at the value chain level, the energy consumption mode is reconstructed through multi-energy collaborative configuration.

Conclusion Natural gas is the key medium to bridge the gap between coal and new energy, and it is very important to build a new energy system. It is necessary to refine the top-level design, promote the integration of industry, university and research, and accelerate the reform of enterprise organization, and fully release its balanced energy value.