Grid resilience measures the impacts of a power outage and how quickly power is restored.
The average power outage length under normal conditions in MO is similar to the national average.
Community and utility investments in local energy resources and grid infrastructure can increase resilience.
Grid reliability refers to the power grid’s ability to maintain normal operation and meet electricity demands (Federal Energy Regulatory Commission 2026). Grid reliability depends on having adequate fuel and infrastructure to maintain electricity supply, and the ability to withstand disruptions without power outages. For more, see Grid Reliability and Sources of Electricity.
Three common metrics for grid reliability include (Pacific Gas & Electric n.d.):
These metrics are typically reported with and without major weather event days. Including all days reflects the overall performance of the grid, while adjusting to exclude major weather-related interruptions reflects day-to-day performance.
Grid resilience refers to how the grid withstands and responds to a power outage (National Academies of Sciences, Engineering, and Medicine 2017). Resilience focuses on reducing the effects of an outage and restoring service quickly after unexpected, high-impact events like severe weather.
Unlike reliability, there is no standardized metric for resilience (Broderick et al. 2022). Proposed methods compare a utility’s performance during a service interruption to its normal performance (Vega Penagos et al. 2023, Hossain et al. 2021).
In MO, investor-owned utilities are required to submit an annual report to the Public Service Commission including reliability metrics like SAIDI, SAIFI, and CAIDI, as well as the lowest-performing sections of the grid in their service area and plans to improve them (20 CSR 4240-23).
Adjusting to exclude days with major weather events, the average length of a power outage in MO is consistent from year to year and is similar to MO’s neighboring states and the national average (Energy Information Administration (EIA) 2025a, Figure 1). MO reported an adjusted CAIDI of 122 and 115 minutes per interruption in 2023 and 2024, respectively, compared to national averages of 119 and 121 minutes per interruption.
The unadjusted CAIDI varies significantly from year to year, mostly due to major weather events (EIA 2025b). Across MO and its neighboring states, unadjusted CAIDI ranged from 116 to 521 minutes per interruption (EIA 2025a). Adjusting to exclude major weather days reduced the range to 90 to 144 minutes per interruption.
Distributed Energy Resources (DERs) are a class of technologies that provide power close to consumers (National Conference of State Legislatures 2025). DERs include generators, rooftop solar systems, and battery energy storage systems, which supply electricity at the local level when the main grid is disrupted.
DERs can be combined into microgrids, which can operate independently from the main grid (Broderick et al. 2022). Microgrid designs vary in size, connection to the main grid, and whether they supply regular power in addition to backup power.
Community centers such as schools, libraries, or churches can also serve as resilience hubs (Baja et al. 2019). These hubs are powered by DERs to provide emergency services for residents in a centralized location.
Utilities can improve grid resilience against extreme weather through a process called grid hardening (Wiser et al. 2025, Hughes et al. 2024). These techniques include upgrading aging equipment and managing vegetation growth around equipment to reduce damage during severe weather events.
Figure 1. Customer Average Interruption Duration Index (CAIDI) for MO, neighboring states, and U.S. in 2023 and 2024. CAIDI measures the average length of power outages for the entire year (blues) and adjusted to exclude major weather events (yellows). While the impact of severe weather on the grid varies by year and location, day-to-day grid performance is relatively consistent between MO, neighboring states, and the national average. Data from EIA 2025b.
References
Baja K, McKinstry-Wu S, Oxnam G, Fitzgerald G (2019) Guide to Developing Resilience Hubs. Urban Sustainability Directors Network. https://www.usdn.org/resilience-hubs.html
Broderick R, Marshall Garcia B, Horn SE, Lave MS (2022) Microgrid Conceptual Design Guidebook. Sandia National Laboratories. https://doi.org/10.2172/1863659
Energy Information Adminstration (EIA) (2025a) Form EIA 861: Annual Electric Power Industry Report. https://www.eia.gov/electricity/data/eia861/
EIA (2025b) Hurricanes in 2024 led to the most hours without power in the United States in 10 years. https://www.eia.gov/todayinenergy/detail.php?id=66744
Federal Energy Regulatory Commission (2026) Grid Reliability and the Role of the Federal Energy Regulatory Commission. https://www.ferc.gov/grid-reliability-and-role-federal-energy-regulatory-commission
Hossain E, Roy S, Mohammed N, Nawar N, Dipta DR (2021) Metrics and enhancement strategies for grid resilience and reliability during disasters. Applied Energy. 290: 116709. https://doi.org/10.1016/j.apenergy.2021.116709
MO Code of State Regulations. Electric Utility Operational Standards. 20 CSR 4240-23. https://www.sos.mo.gov/CMSImages/AdRules/csr/current/20csr/20c4240-23.pdf
National Academies of Sciences, Engineering, and Medicine (2017) Enhancing the Resilience of the Nation’s Electricity System. The National Academies Press. https://doi.org/10.17226/24836
National Conference of State Legislatures (2025) Distributed Energy Resources 101. https://www.ncsl.org/energy/distributed-energy-resources-101
Pacific Gas & Electric (n.d.) Electric reliability reports. https://www.pge.com/en/about/pge-systems/electric-systems/electric-reliability-reports.html
Vega Penagos CA, Diaz JL, Redriguez-Martinez OF, Andrade F, Luna AC (2023) Metrics and Strategies Used in Power Grid Resilience. Energies. 17(1): 168. https://doi.org/10.3390/en17010168
