Energy prediction for community water supply: An integrative application of scaling analysis and life cycle assessment

Community water supply is the local, consumer-level segment of water supply. For its ubiquity, an ability to predict the energy demand for community water supply would help better quantify the water-energy nexus at the community level. However, communities differ in size and distance from the water source, among other variations; no formalism is currently in use for making this energy prediction. Here, we describe a conceptual model and mechanistic formulation for predicting the energy demand of a community water supply in the context of a regional, multi-community supply system. We make the novel methodological integration of scaling analysis and life cycle assessment to account for both network effects and life cycle effects on energy intensity. We also make the novel mechanistic integration of hydraulic energy loss and allometric energy scaling to account for both linear transmission energy and nonlinear distribution energy. With these integrative steps, we create a novel “leaf on a stem” network model and mechanistically parameterized formula for predicting the energy demand of a community water supply, given in life cycle quantity and as the sum of community distribution energy in sublinear scaling with community size and regional transmission energy in linear scaling with the community’s distance from the regional water source. We validate the predictive model by empirically verifying the model parameters through a detailed case study of consumption communities within a regional supply system in the US Great Lakes region. This simple, mechanistic predictive model may help substantiate the concept of water-energy nexus and facilitate energy assessment for community water supply.