Renewable Energy, Efficiency, and Waste Management for Firm Competitiveness: Exploring Heterogeneity in Policy Effectiveness

China’s transition toward a low-carbon and sustainable energy system requires renewable energy firms to align their technological decisions with environmental policy objectives. Drawing on the Porter hypothesis, this study examines how command-and-control, market-incentive, and voluntary environmental regulations influence firms’ utilization of three sustainable energy technologies (SETs): renewable electricity, energy-saving technologies, and waste management. It also assesses how these technological practices contribute to firm competitiveness. Survey data collected from 273 renewable energy firms in China’s hydropower, wind, and solar sectors were analyzed using partial least squares structural equation modelling. The results show that command-and-control and voluntary environmental regulations positively influence all three SET dimensions. Market-incentive environmental regulation positively affects energy-saving technologies and waste management but has no significant effect on renewable electricity utilization. Renewable electricity, energy-saving technologies, and waste management all positively contribute to firm competitiveness. These findings provide conditional support for the strong Porter hypothesis by demonstrating that technological responses that can improve firms’ competitiveness depend on the alignment between the regulatory instrument employed and the technology targeted. This study provides firm-level evidence for designing differentiated regulatory strategies that support both China’s decarbonization objectives and the competitiveness of renewable energy firms.