As China pursues its dual carbon goals—peaking carbon emissions by 2030 and achieving carbon neutrality by 2060, the energy sector is central to the country’s climate strategy. This study investigates the impact of Environmental, Social, and Governance (ESG) performance on firm value in China’s energy sector, an industry critical to national carbon emissions and energy consumption. Using a panel dataset of 20,225 firm-year observations from A-share listed firms between 2016 and 2023, we apply regression models to assess how ESG performance affects firm value, with controls for industry characteristics and policy effects. The results show that ESG performance significantly enhances firm value, especially among non-state-owned firms and those in high-pollution industries. ESG performance also facilitates access to green bond financing, providing firms with enhanced capital for green investments, thereby boosting market value. Furthermore, we find that firms in regions with higher green development attention benefit more from ESG practices, with local carbon trading policies playing a key role in improving firm competitiveness and market performance. This study provides critical insights into how ESG strategies and carbon governance policies influence firm performance in the energy sector. The findings offer practical implications for policymakers aiming to support low-carbon industrial transformation and for firms seeking to integrate sustainability into their long-term strategic planning. These insights are crucial for driving the successful implementation of China’s dual carbon strategy.