Study on the impact of reducing fossil energy use on China's existing economic structure under carbon neutrality goals

China's higher fossil energy use places some constraints on the low-carbon transition of its economic development model. Unlike the research on energy transition pathways under carbon reduction targets or the simulation of carbon reduction effects under "portfolio" policies, the study takes China as an example, incorporates the reduction of fossil energy use into the theoretical framework of sustainable development, and adopts computable general equilibrium (CGE) theory to construct a closed macroeconomic system to describe China's existing economic structure. The main objective of the study is to discuss the impacts of fossil energy use reduction on China's existing economic structure under the carbon neutrality goal, and to develop new research ideas for countries around the world to achieve carbon neutrality with high quality. We find that the reduction in fossil energy use has a large impact on the current structure of China's economy. Both MM and related manufacturing sectors have maximum output declines of more than 11.3%. The Ser sector has the smallest impact, with a maximum output decline of 9.1%. Because sectors such as Electricity and Hot Water Combustion mainly rely on fossil energy sources such as coal to generate electricity, their output is the most affected compared to other sectors, with a maximum output decline of 22.69%. In addition, the dynamic simulation relies on the reduction of fossil energy use to drive China's existing economic structure to seek a new equilibrium. Specifically, the output of the Ser sector grows by about 34%, and the task of regional economic development has been gradually taken over by the tertiary sector. The output of the GDP, Emp, EV, FPM, TI, and Tra sectors do not change by more than 5%, and the output of the EP sector declines by a maximum of about 11.14%. Sectoral outputs such as electric hot water combustion fall by a maximum of about 29.04%. In addition, in 2060, the decline in output in sectors such as MM, CM, GSME, and HAM reaches its limit value, with output decreasing by -63.21%, -41.48%, -68.20%, and -39.77%, respectively.