Can China's renewable energy policy synergies help clean energy transition?

Energy transition as a key strategy for achieving climate goals is garnering global attention, with nations actively employing renewable energy (RE) policy instruments to facilitate this shift. Despite extensive research on individual policy impacts, the synergistic or trade-off effects of multiple policies on energy transition require further exploration, especially in countries with market conditions similar to China. This study introduces a provincial energy transition index (ETI) and employs text and association rule mining to discern the policy intensity and key synergies of China's typical RE policies (including feed-in tariff (FIT), carbon emission trading (CET), tradable green certificates (TGC), electricity market (EM) reform, and renewable portfolio standard (RPS)). Based on provincial panel data from 2006 to 2022 in China, their effectiveness is evaluated using a difference-in-differences (DID) estimation. Empirical results indicate that: (1) the national ETI increased by 10.3 % during the study period, with significant regional disparities. (2) three key policy synergies—EM-TGC, FIT-EM-TGC, and RPS-EM-TGC—were identified, with their temporal evolution reflecting a shift in China's energy transition policies from administrative to market-oriented mechanisms. (3) synergy analysis reveals that the EM-TGC synergy is more effective than the standalone TGC policy, and the coordination of FIT further enhances the EM-TGC synergy in current stage of energy transition. Compared to other policy combinations, the RPS-EM-TGC combination is more effective, promoting synergistic development in new energy generation, grid integration, and market absorption. Beyond the China context, this analysis contributes to policy discourse on advancing energy transition in regulated markets.