Resilience at the last mile: Resilience standards and metrics for the distribution system

This brief examines how power system resilience should be assessed and strengthened at the distribution network level, where electricity service reaches end users. The note argues that as countries pursue universal electrification, resilience must be measured not only through system-wide asset performance but also through the ability of distribution systems to maintain and rapidly restore electricity services to communities, critical facilities, and vulnerable customers during disruptive events. The publication applies the MARC framework (Minimize, Absorb, Recover, Contribute) to distribution system resilience and distinguishes between resilience standards, which define technical and operational requirements, and resilience metrics, which evaluate performance outcomes.

It presents a structured set of standards and indicators covering infrastructure hardening, climate risk exposure, feeder configuration, distributed energy resources, microgrids, outage management, restoration planning, cybersecurity, and post-event adaptation. Particular emphasis is placed on customer-centric and community-focused metrics such as outage risk, critical load served, restoration time, service continuity, and population access to electricity during emergencies. Drawing on real-world experiences from Puerto Rico, San Diego Gas & Electric, and Australia’s bushfire resilience initiatives, the note demonstrates how utilities can improve resilience through data-driven planning, grid modernisation, operational preparedness, and continuous learning. It concludes that while comprehensive resilience frameworks and metrics are available, the primary challenge for many utilities, especially in developing countries, remains the availability of reliable, geolocated asset and customer data. Strengthening data systems and asset inventories is therefore identified as a foundational step toward building resilient and adaptive distribution networks.