Simultaneous co-optimization for the economic dispatch of power and water networks

Water distribution and power transmission networks are thought of as separate uncoupled infrastructure systems. In reality, they may be viewed as a single system which may be called the energy-water nexus. In hot and arid climates, this nexus takes on a deeper meaning in terms of the economic dispatch of power, water and cogenerating desalination units. This paper represents a co-optimization framework for the economic dispatch of water and electric power. In particular, an optimization program is provided that minimizes total costs as a function of power and water generation subject to demand, capacity and process constraints. It is distinct from existing literature in that it focuses on the simultaneous optimal operation of all plants within the power and water delivery networks within a generalized mathematical formulation. The optimization was then demonstrated on a hypothetical system composed of four power plants, three cogenerators and one pure water plant. Interesting results were observed suggesting that the cogenerator minimum capacity limits and process constraints can lead to scenarios where cheaper single product plants can be crowded out of the dispatch. The program provides a systematic method of achieving optimal results and can serve as basis for set-points upon which individual plants can implement their optimal control.