Stress Testing Methods for Evaluating Resilience to Extreme Events: Valuing Interregional Transmission outlines a methodology to develop stress tests of power systems to assess their resilience to extreme weather events. The methods employed also focus on enhancing stress testing practices to assess the resilience value of interregional transmission during extreme events.
This report is accompanied by a case study, “Stress Testing the Southwest Power Pool: Evaluating the Role of Interregional Transmission in Supporting SPP Resilience to Extreme Events,” and builds on the task force’s prior report, Interregional Transmission for Resilience: Using Regional Diversity to Prioritize Additional Interregional Transmission.
The electricity grid is adapting to shifting resource portfolios, increasing electrification, and the growing impact and frequency of extreme weather events. New analytical practices are needed to conduct stress testing simulations on current and future power systems in order to better understand system reliability during high-impact, low-probability events—such as recent winter storms affecting the Texas and Eastern Interconnections and wide-area heat domes across the Western Interconnection. Reliability planning today often simplifies or omits resource availability in neighboring systems, but the stress testing practices outlined in this report and accompanying case study of the Southwest Power Pool (SPP) use grid topologies that include various representations of neighboring systems to isolate the resilience value of interregional transmission.
By assessing a smaller set of critical conditions, planners can analyze grid risks, mitigations, and operational considerations in detail, including adding greater resolution of neighboring regions and their transmission capabilities. Planners can thus determine which grid improvements, including interregional transmission, can most cost-effectively support grid reliability during high-impact, low-probability events.
The report outlines a four-step stress testing framework to guide planners in developing their own stress tests for system planning. A case study was also conducted for a future (2029) Southwest Power Pool system to implement stress testing principles and evaluate the resilience value of interregional transmission. The case study assessed the resilience value of interregional transmission during extreme events for the Southwest Power Pool by analyzing the system with and without detailed interregional transfer capability. In the simulations performed for this case study, interregional transmission mitigated almost all load-shed risk. This shows that existing interregional transmission offers significant resilience today, and points to potentially greater benefits if transfer capabilities between regions are expanded.