Does the reduction of CO2 emissions from renewable energy generation vary depending on economic and industrial structure? Empirical evidence from major CO2 emitting countries

The urgent need to mitigate climate change compels countries to adopt renewable energy generation as a key strategy for reducing CO2 emissions. However, insufficient understanding of the conditions and effectiveness of this approach in different economic and industrial structures has led some countries to fall short of their CO2 emission reduction targets. Therefore, this study selected panel data from 36 major CO2 emitting countries form 2005 to 2020, and used a threshold model to estimate nonlinear impacts of renewable energy power generation on CO2 emissions under different economic levels, industrial structure, and environmental policy. Results showed that renewable energy generation strategy effectively reduces CO2 emissions only in countries surpassing specific thresholds: 1) per capita GDP >15,975USD, 2) energy intensity <0.141 tons of oil equivalent/USD, or 3) CO2 intensity <0.348 tons of CO2/USD. Conversely, below these thresholds, renewable energy generation strategy shows limited or even counterproductive effects due to technological limitations, fossil-reliant industrial structures, or weak environmental governance. Those findings challenge one-size-fits-all climate strategies. Thus, countries with higher economic levels should vigorously develop renewable energy generation strategy to reduce CO2 emissions. Conversely, countries with higher energy intensity should pay more attention to industrial structure transformation to reduce CO2 emissions, and countries with higher CO2 intensity should pay more attention to enhance environmental laws and regulations to reduce CO2 emissions. This research provides a new framework for tailoring energy transition policies to national development stages, offering critical insights for achieving Paris Agreement Targets.