Regional energy-environmental performance and investment strategy for China's non-ferrous metals industry: a non-radial DEA based analysis

Globally, China is the largest producer and consumer of common non-ferrous metals. China's non-ferrous metals industry is energy intensive, accounting for 24% of the total industrial energy consumption in 2011. In this study, we adopted a non-radial DEA model to examine the energy-environmental performance of the non-ferrous metals industry from a regional perspective during the 2006–2011 period. The energy-environmental performance was evaluated by the eco-efficiency under natural disposability (EN), eco-efficiency under managerial disposability (EM), eco-efficiency under natural and managerial disposability (ENM) and ENM with desirable congestion (ENM (DC)). Based on the EN, both the energy conservation and emission reduction potentials were calculated. Additionally, the investment strategy was confirmed by regional types of damages to return (DTR). In the second-stage study, the factors influencing eco-efficiency were measured using Tobit regression and truncated regression models. The results indicated that the efficiency scores of EN, EM, ENM and ENM (DC) were considerably different. Investment was effective in improving the energy-environmental performance for twenty-one regions during the whole study period. Henan had the highest energy conservation and emission reduction potentials. The results obtained from the regression models were similar, which displayed that the population density and energy price were responsible for the increase in eco-efficiency while economic development level and industrial structure affected eco-efficiency negatively. Based on these results, policy recommendations for the non-ferrous metals industry to improve their performance in a low-carbon economy are suggested.