Modeling and integration of water desalination units in thermal unit commitment considering energy and water storage

In this paper, a new short-term daily scheduling model is proposed and formulated. In the proposed model, thermal power plant will be optimally scheduled in a system with water desalination units. For the thermal units, various cost terms including start-up, shut-down, and also fuel cost are considered and modeled. Also, thermal dynamics of the plants including power generation ramp-up and ramp-down, minimum up and down time limits, and start-up and shut-down ramps are considered. In addition, energy storage batteries as well as water storage tanks of the desalination units are modeled. The proposed model is a mixed integer linear programming (MILP) for simultaneous scheduling of thermal power plants and desalination units while considering transmission constraints. Power and water balance at the network buses in addition to the power flow constraints of the lines are considered. Various membrane and thermal desalination methods are modeled. The proposed model is implemented on a test case and the simulation results show a significant reduction in the system operating costs as well as improved performance of both the thermal power plants and the desalination unit. The proposed scheduling method can be used for the various future studies of joint power-water production and coordination.