The aim of this study is to investigate the relationship between green technology R&D investment and corporate performance (ROA) of 44 Beijing-listed energy companies from 2016 to 2021 using a threshold regression model. The results show that there is an inverse W-shaped nonlinear relationship between green technology R&D investment and firm performance. This means that green technology R&D investments only have a positive effect on firm performance within an appropriate green technology R&D investment interval, and a negative effect occurs outside this interval. Additionally, the study analyses the influence of three threshold variables (firm size, capital structure and capital density) on the relationship between green technology R&D investment and firm performance. The results show that firm size has an inversely- U-shaped relationship, the capital structure has a negative nonlinear relationship and the capital density has an inversely N-shaped relationship. Optimal intervals are observed for all three threshold variables. Moreover, the study shows that the green technology R&D investment intensity has a lagged effect on firm performance. The positive influence weakens over time, and the negative influence becomes more pronounced. The findings of the study can help energy companies to develop green technology R&D innovation strategies, such as differentiating green technology R&D expenditures for companies in different development situations. It can also exploit the driving effect of green technology R&D investment on firm performance in the context of China’s energy sector restructuring.

This study examines the mutual relationships among ESG performance, total factor productivity (TFP), and energy efficiency (EE) in a sample of Chinese A-share listed firms from 2010 to 2022. This study shows that ESG has a significant promotional effect on TFP. Reducing financing constraints and inefficient investment are among the mediating mechanisms, and the latter plays a greater role. Heterogeneity analyses suggest that state-owned enterprises (SOEs) and heavy-polluting enterprises (HPEs) should be consistently committed to ESG responsibility fulfillment. Formal environmental regulation (FER) can be complementary to ESG, but informal environmental regulation (IER) has the opposite effect. TFP was instead suppressed by the triple combined effect of ESG with these two. The results of the threshold effects of ESG and EE indicate that the positive impact on EE becomes more pronounced as ESG performance improves. However, ESG performance varies across subdimensions. As green technology research and development efficiency (GRDE) and green technology transformation efficiency (GTTE) improve, stronger ESG promotes EE. This threshold effect also exhibits heterogeneity with respect to the ownership structure. Moreover, there is bidirectional causality between EE and TFP, and EE has a stronger positive effect on TFP. These findings reveal the optimal paths and potential risks for moving toward sustainability for firms.