Choice of technological change for China's low-carbon development: Evidence from three urban agglomerations

China's three urban agglomerations, namely, "Beijing-Tianjin-Hebei", "Yangtze River Delta", and "Pearl River Delta", are the most developed regions in China. These agglomerations are also expected to play a leading role in China's low-carbon development. Energy-saving and carbon-free technological changes play key roles in the low-carbon development transformation of these regions. This study investigates the elasticities of the output and substitution of factors, and the biased technological change in the three urban agglomerations based on the stochastic frontier analysis with a translog production function. The results indicate that the economic growth of the three urban agglomerations is mainly driven by the increase in capital stock caused by investment, energy shortage, and environmental degradation. The relationship between electricity input and carbon dioxide emissions is affected by power generation and economic cycles and transforms from complementarity to substitution. However, this relationship varies among regions. Technological change is conducive to electricity saving, but it does not present an emission-reduction effect.