S1 Appendix -

<div><p>One of the actions taken to mitigate the climate change is research, development and demonstration (RD&D) investments in renewable energy (RE) technology. In addition to domestic RD&D spending, the import of foreign technologies, as a main channel of technology transfer, is another option to obtain higher share of renewable energies in order to achieve climate objectives. In this study, a panel dataset of 28 OECD member countries from 2011 to 2020 is analyzed, using the OLS, fixed-effects, and two-step system GMM methods, to assess the impacts of public spending on renewable energy RD&D (RERD) and the import of renewable energy technologies on the energy-related CO<sub>2</sub> emissions. To fully capture the significant regional differences, the 28 countries are re-divided into four regions in accordance with their renewable energy RD&D investment level and total CO<sub>2</sub> emissions. This study uniquely investigates the impact of RERD and importation–as an alternative channel for obtaining renewable energy technologies–on energy-related CO<sub>2</sub> emissions in OECD countries, while also analyzing regional differences to inform targeted local policies. The findings reveal that CO<sub>2</sub> emission is significantly and negatively affected by renewable energy imports, for the full panel as well as for Low-RERD and Low-Emission regions. Furthermore, only in High-RERD and High-Emission regions can renewable energy RD&D decrease CO<sub>2</sub> emissions. Accordingly, some policy implications are recommended concerning investments in renewable energy RD&D and renewables import.</p></div>