Assessing Trade-offs Between Water, Emissions, and Cost in Multi-objective Optimal Power Flow

The emissions and water use of power systems have been independently incorporated into sub-hourly operational timescale problems. However, fewer studies have proposed methods that allow for the direct incorporation of emissions, water use, and cost into sub-hourly grid operations. Therefore, this study proposes a multi-objective formulation of the optimal power flow problem where emissions, cost, thermoelectric power plant water consumption, and thermoelectric power plant water withdrawal are all to be minimized. Such a multi-objective formulation allows grid operators to (1) quantify the degree to which cost, water, and emissions impact one another, as well as (2) observe what new operational policies are introduced when compared to traditional cost-only OPF formulations. This multi-objective formulation does not require reformulation into a single objective equivalent, but rather is a tool to show trade-offs between objectives. Insights into the multi-objective trade-offs of power systems can ultimately help identify within-system vulnerabilities, as well as quickly compare vulnerabilities across power systems. We demonstrate our methods on the IEEE 30-bus system.