Quantitative engineering systems modeling and analysis of the energy-water nexus

The energy-water nexus has been studied predominantly through discussions of policy options supported by data surveys and technology considerations. At a technology level, there have been attempts to optimize coupling points between the electricity and water systems to reduce the water-intensity of technologies in the former and the energy-intensity of technologies in the latter. To our knowledge, there has been little discussion of the energy-water nexus from an engineering systems perspective. A previous work presented a reference architecture of the energy-water nexus in the electricity supply, engineered water supply and wastewater management systems developed using the Systems Modeling Language (SysML). In this work, bond graphs are used to develop models that characterize the salient transmissions of matter and energy in and between the electricity, water and wastewater systems as identified in the reference architecture. These models, when combined, make it possible to relate a region's energy and municipal water consumption to the required water withdrawals in an input-output model.