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

Abstract

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.

An Integrated Energy and Water Market for the Supply Side of the Energy-Water Nexus in the Engineered Infrastructure

“…It builds upon previous work [2,3,30] that presented the corresponding economic dispatch problem. The formulation was implemented and solved using MATLAB and GAMS.…”

“…The optimization program in the previous section was demonstrated on a hypothetical test case adapted from previous efforts focussed on the corresponding economic dispatch problem [2,3,[27][28][29]. This data is selected for two reasons: 1) The timing of power and water demand peaks and troughs is typical in the GCC and, 2) the range of the power and water demands is exaggerated to demonstrate the convergence capability of the selected optimization engine .…”

“…The first, economic dispatch, would determine the optimal output of a number of electricity generation facilities, water treatment plants, and cogeneration plants to meet the water and power demands, at the lowest possible cost, subject to transmission and operational constraints. A model for the joint economic dispatch of both power and water in such a market has been presented in previous work [2,3]. The economic dispatch problem assumes that all facilities considered are online and ready to produce.…”

“…Recently however, a number of power-water grid cooptimization programs have been developed [2,3,[27][28][29]. These efforts have focussed on the economic dispatch of power, water and cogeneration plants in which all plants are assumed to be ready to produce.…”

“…In Section 3 a formulation for unit commitment of power, water and cogeneration plants is presented. The unit commitment model, like the previously developed economic dispatch models [2,3,[27][28][29] is developed with the aim of supporting discussion of the potential for integrated energy and water markets. It, however, can be directly implemented in the integrated water and electricity authorities that already exist in many countries in the GCC.…”