Case beyond historical severity: Winds, faults, outages, and costs for electric grid

In recent years, global energy systems have experienced multiple disruptions from known threats at unprecedented severity, causing costly impacts in broader and unexpected domains. This work attempts to improve the understanding of such severity-dependent impact change for the historically unprecedented but meteorologically plausible windstorm on the present Finnish electricity grid. The wind gust speed field of the unprecedented windstorm is obtained by scaling the field of the historically most impactful windstorm upwards by 24%, a value obtained with the extreme-value-theory-based method. Windstorm impacts on the electricity supply are computed with a fragility-based electricity grid impact model, accounting for medium voltage line faults and repairs throughout the country. The lost load from 24% higher wind gust speeds increases tenfold. Impacts are limited by the significant cabling of powerlines done since 2011. The obtained spatiotemporal lost load profile provides a basis for the identification and quantification of extreme windstorm costs as well as a realistic case for broader emergency preparedness exercises. The former application is illustrated by the preliminary cost-benefit assessment for cabling in the case of an unprecedented windstorm. Finally, the reevaluation of currently used cost rates calls for an account of time dependency, critical services, and impacts on smaller economic and population segments.