A Water-Energy Nexus Approach for the Co-Optimization of Electric and Water Systems

The staggering increase in water production, driven by population and economic growth, has consequently led to a massive increase in energy demand, particularly in countries that rely on desalination. Hence, the concept of the water-energy nexus has emerged as the best option to alleviate the gap between the demand and production of both water and power. This paper proposes a new approach for co-optimizing water and electric power systems by incorporating the energy-intensive equipment involved in water desalination and distribution. The proposed procedure leverages the energy flexibility of reverse osmosis (RO) desalination tracks. RO tracks can operate alternatively in conjunction with water network storage tanks with variable-speed pumps to optimal satisfy water demand at minimum energy and operating costs. The developed model takes into consideration the essential constraints of both the power and water systems to meet consumer demands. Further, a mixed-integer nonlinear programming model is proposed for the day-ahead operation of the two integrated systems. The simulation findings show that the suggested technique is successful in scheduling the energy-intensive equipment in the two systems to achieve a
$\$ $
26,993 per day savings compared to a 4.6% decrease in overall operating costs when compared to optimizing each system independently.