Reston, VA. – The Energy Systems Integration Group (ESIG) has released a fact sheet titled “Wide-Area Resource Adequacy Assessments: Probabilistic RA planning for Interconnected Grids,” describing the need for, and key elements of, interconnection-wide or continental resource adequacy assessments. These wide-area resource adequacy assessments can provide a clearer understanding of how regions may be able to assist one another during system stress, while supporting and validating local and regional assessments.
Each region, when evaluating whether the grid’s resource mix can serve demand across a range of uncertainties, typically plans in isolation. Regions use different resource adequacy criteria, methods, and assumptions, a siloed approach that makes it difficult to evaluate system-wide risks or fully capture the benefits of interregional coordination. But without a clear understanding of how regions may be able to assist one another during system stress, planners risk both overbuilding in some areas and underpreparing in others. A wide-area resource adequacy assessment can fill this gap.
“North America’s power grids are some of the most interconnected in the world, yet planning for resource adequacy remains fragmented across dozens of utilities, system operators, and planning coordinators,” said Derek Stenclik, chair of ESIG’s task force on resource adequacy. “It’s time we establish a continent-wide approach to assess the reliability of the entire system.”
A wide-area resource adequacy assessment spans multiple regions and planning authorities, and can assess both near-term risks and long-term needs under shared assumptions about load, weather, outages, and transmission. A wide-area resource adequacy assessment will help system planners understand the risks of large weather events, track system-wide changes in load and generation, and evaluate the role of interregional transmission in enhancing reliability and efficiency.
“A wide-area resource adequacy assessment gives planners a common view of system risk—grounded in consistent scenarios, weather data, and modeling assumptions,” said James Okullo, ESIG’s director of system planning. “It doesn’t replace local planning, but rather strengthens it by showing how regions interact, where support is realistic, and where gaps could emerge under stress.”
Wide-area assessments help identify when and where regional support is likely to be available, or limited, under extreme conditions. And they offer a common framework that can help align accreditation methods and reserve margin assumptions in local assessments, supporting fair competition and informed investment and retirement decisions across regions.
Three elements of this wide-area approach are especially critical: scenario-based planning, transparent modeling of interregional transfer capability, and the use of wide-area, correlated, and consistent weather data. A coordinated, probabilistic wide-area resource adequacy assessment is essential to ensure reliability, reduce unnecessary costs, help harmonize accreditation methods, and unlock the full value of coordinated reliability assistance and interregional transmission. By better aligning planning across regions, such an assessment provides a clearer picture of system-wide risks and supports smarter, more efficient investment and policy decisions.
The fact sheet, along with ESIG’s other work related to resource adequacy, can be found here: https://www.esig.energy/redefining-resource-adequacy/
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