Optimizing the energy and water conservation synergy in China: 2007-2012

China's Eleventh Five-Year Plan and Twelfth Five-Year Plan explicitly proposed the strict control of the total amount and intensity of energy and water consumption. However, the synergy between energy and water resources conservation has rarely been taken into consideration, thereby making it difficult to maximize conservation. This study selects three major energy sectors for the assessment and optimization of the synergy between energy and water conservation. The results of the critical paths show that during the energy generation process, the chemical industry, the smelting and pressing of metals, and the mining and processing of nonmetal ores are coupling sectors, which use a combination of large amounts of energy and water resources. The implementation of energy- and water-saving actions in these sectors would effectively promote the synergistic energy- and water-conservation effects. The multi-objective optimization results suggest that the increased intensity of structural adjustment effectively enhanced synergy. Under the premise of a stable economy, the synergy could be improved by optimizing the output structure of each sector, especially coupling sectors in the flow paths of energy and water resources.