Evaluating investments in electricity resilience: evidence from California's Public Safety Power Shutoff (PSPS) events.

Cascading failures and compound effects in electricity systems are a growing concern for infrastructure resilience, as they increasingly lead to additional hazards (e.g., wildfires), further exacerbating power disruptions. In California, investor-owned utilities (IOUs) have responded to these threats by enacting Public Safety Power Shutoffs (PSPS), which are proactive de-energization of high-risk circuits, to reduce wildfire risk. Although prior research has examined PSPS impacts, little is known about whether physical infrastructure investments have reduced de-energizations on the most frequently affected circuits. This study addresses that gap by evaluating whether circuit-level investments have decreased the frequency or severity of PSPS events in California. We overlay investment and de-energization data at the circuit level to conduct this analysis. Despite limited data for certain investments, early results suggest that these investments are not associated with a reduction in the frequency or severity of de-energizations. Moreover, external wildfire risk factors alone do not seem to explain these patterns, suggesting that internal utility decision-making and other risk factors (e.g., aging infrastructure) play a critical role in which circuits are de-energized. These results underscore the importance of considering alternative investment strategies in physical infrastructure upgrades, like distributed energy resources (DERs), to minimize the impact of de-energizations on the most impacted circuits.