[Impact of China's Environmental Regulations on CO₂ Emissions in the Power Sector]

CO₂ emissions from the power sector are the main source of CO₂ emissions in China， and environmental regulation plays an irreplaceable role as a basic constraint for reducing carbon emissions. Based on China's provincial panel data from 2003-2019， this study analyzes the spatio-temporal characteristics of different types of environmental regulatory intensity and CO₂ emissions from the power sector by using kernel density estimation and standard deviation ellipses. Then， the geographically and temporally weighted regression model is constructed to explore the impacts of command-based， market-based， and voluntary environmental regulations on CO₂ emissions in the power industry. The results showed the following： ① For different types of environmental regulation： in time， the market-based environmental regulation kernel density curves showed a "rightward" motion， with interregional differences expanding， while command-based and voluntary environmental regulation showed a shrinking interregional difference； in space， command-based environmental regulation gradually followed a northwest-southeast spatial distribution pattern. Market-based and voluntary environmental regulation all showed a northeast-southwest spatial distribution pattern. ② For CO₂ emissions from the power sector： in time， kernel density curves showed a "rightward" motion， with inter-regional differences expanding； in space， there was a gradual pattern of northwest-southeast spatial distribution pattern， and the center of gravity was moving to the northwest. ③ The impact of different types of environmental regulations on CO₂ emissions in the power sector had obvious spatial and temporal heterogeneity. In time， the regression coefficient of command-based environmental regulation in most provinces （cities， autonomous regions） had an increasing and subsequently declining trend， while market-based and voluntary environmental regulation decreased first and then increased. In space， spatial heterogeneity in the role of the three types of environmental regulation was evident； command-based environmental regulation gradually had a greater impact on the northern provinces （facilitation）， market-based environmental regulation had a greater impact on the central-eastern provinces （facilitation）， and voluntary environmental regulation had a greater impact on the eastern provinces （disincentive）.