Coordinating the Operation of Water Desalination and a Renewables-Rich Electric Power Grid

Handling the variability associated with integrating large capacities of renewable energy sources (RES) into the power grid is a challenge that is increasingly influencing the operation of the power system. At the same time, the growing need for water desalination to produce sufficient freshwater in arid areas increases the importance of suitable energy sources for sustainable operation of water desalination plants. However, as power and water system operators have traditionally operated their systems in isolation, there is a lack of understanding of the interdependence and interactions between these two systems. This research addresses this gap by proposing a co-optimization framework that coordinates the operation of a renewable-rich power system with the operation of gridconnected, reverse-osmosis (RO) water desalination plants (WDP) to minimize their combined operational costs and maximize the utilization of RES. From the power system operation standpoint, these WDPs can be considered as flexible demands. In this context, a unit commitment model will be presented that integrates the energy flexibility of WDPs into the day-ahead power system scheduling. The proposed model takes into account the operational constraints of both power and water desalination systems, thus cooptimizing their operation without compromising the reliable supply of power and water to endusers. Some of the WDP constraints are expected to be nonlinear. Hence, to reduce the computational burden, a linearized model will be developed. The developed co-optimization framework will also take into account the uncertainty associated with the problem at hand, such as the uncertainty due to electric power demand, water demand, and wind and solar production. Preliminary simulation results on a basic model show that applying this proposed technique significantly reduces the cost of energy consumed by WDPs. Moreover, by implementing the energy flexibility of WDPs, the daily operation cost of the power system is decreased, the electricity demand peak is decreased, and the renewable urtailments are reduced. These benefits can be achieved merely by coordinating the WDPs operation and the power system operation, without involving any additional infrastructure. evertheless, more advantages can be gained by enhancing the water network to handle the total available energy flexibility that can be provided by WDPs to the power system operator.