System and sub-system energy resilience during public safety power shutoffs (PSPS) in California -- An evidence-based argument

TL;DR

This paper analyzes California's Public Safety Power Shutoffs (PSPS) to understand how system and sub-system resilience balance wildfire mitigation with minimizing local disruptions, highlighting the importance of infrastructure investments.

Contribution

It provides an evidence-based analysis of PSPS impacts at circuit-level, revealing differences in outage frequency and impact, and emphasizes the temporal nature of resilience influenced by infrastructure planning.

Findings

Higher impact de-energization events are less frequent.

Frequent impacts are associated with lower customer and duration impacts.

Resilience is primarily driven by infrastructure and planning investments.

Abstract

This study examines historical relationships between Public Safety Power Shutoffs (PSPS) events enacted by California's investor-owned utilities (IOUs), at the system and sub-system levels, along with other disruptions to macro electricity systems. This study contributes to understanding the balance between system-wide resilience goals, such as wildfire hazard mitigation, and sub-system-level priorities, such as minimizing the frequency and duration of localized disruptions. Focusing on circuit-level data from 2018 to 2023 as a proxy for sub-systems, we evaluate differences in outage frequency, duration, and customer impact across three major IOUs in California. Results highlight a differentiation between 'higher impact' de-energization events, which have occurred less frequently, and circuits impacted frequently but with lower customer or duration impacts. Study outcomes suggest that resilience, from the perspective of PSPS events, may be more temporal, which in this case is driven by infrastructure and planning investments by IOUs. Future work aims to incorporate socio-demographic factors, including urban-rural divide, to identify further opportunities to enhance resilience at the circuit and sub-circuit levels.