Synergy pathway innovation of carbon emission trading, tradable green certificate and green power trading policies: achieving China’s dual carbon goals

The carbon emission trading scheme (ETS), tradable green certificate (TGC) and green power trading (GPT) policies are vital for promoting energy transformation and carbon reduction under the dual carbon goals. However, the effects of and relationships among multiple policies urgently need to be studied. In this work, the panel data of 30 provinces in China from 2010 to 2023 are used. First, through the multiperiod difference-in-differences (DID) method, fixed effect models and mediating effect models, the carbon reduction effects of the pilot and national ETS policies, the renewable energy development effects of the TGC and GPT policies, and the multipolicy synergy effect are examined. A dual machine learning model is innovatively introduced to test the robustness of the results. Second, the slack-based measure–directional distance function–global Malmquist–Luenberger (SBM–DDF–GML) method is used to calculate the GTFP and investigate its transmission effect on policies. Finally, the impacts of the ETS, TGC and GPT policies on fossil fuel consumption are further analysed. The results indicate the following. (1) The pilot ETS policy reduces carbon emissions and carbon intensity, whereas the national ETS policy increases carbon emissions and carbon intensity in the short term. The TGC and GPT policies increase renewable energy generation and its proportion. (2) The synergy of the pilot ETS and GPT policies is the best for reducing carbon emissions and carbon intensity. The synergy among national ETS, TGC and GPT policies is optimal for developing renewable energy. In addition, there is redundancy between the TGC and GPT policies. (3) The pilot ETS policy inhibits GTFP, whereas the national ETS, TGC and GPT policies promote GTFP. The GTFP significantly reduces carbon emissions and carbon intensity and increases renewable energy generation and its proportion. (4) Both the pilot ETS and national ETS policies reduce the intensity of fossil fuel consumption. The GPT policy reduces the total level of fossil fuel consumption, whereas the TGC policy increases this level. In this work, innovative decarbonisation policies synergy pathways and insights into achieving green and low-carbon transitions in China and other developing countries are provided.