Employing Input-Output Model to Assess the Water Footprint of Energy System

The vigorous development of the energy system has imposed a huge burden on the environment, especially for the water environment. On the one hand, the production of energy products requires a large amount of water resources. On the other hand, the environmental pollution caused by the energy system requires a large amount of dilution water. In order to quantify and assess this environmental pressure brought by the energy system, an optimized model is necessary. In this chapter, we start from the concept of water footprint to explain the significant impact of the energy system on the environment. Then we compare the two water footprint evaluation ideas (one is top-down, and another is bottom-up), and led to a more commonly used method, the input–output model. In addition to introducing the basic principles and development process of this model, we also use three case studies to specifically reveal the application of this method in energy and water environment accounting. We hope that our discussion can help readers better understand the function and research results of input–output models in the field of environmental assessment, thereby promoting the further application and deepening of input–output models in the environmental field.