Customers always pay the ultimate price for power outages, yet the focus of power system resilience lays in strengthening distribution and hastening recovering would be most cost-effective, as opposed to measures that focus on making the power grid more resilient.
This is according to a new report by Grid Strategies, LLC, in which the authors claim power system reliability and resilience are deeply intertwined — reliability covers those long-term and operational steps that reduce the probability of power interruptions and prevent loss of customer load, while resilience measures reduce damage from outages and hasten restoration and recovery to shorten outage durations. Many reliability measures improve resilience and the same utilities and system operators that are responsible for providing reliability also provide resilience. In practice, bulk power system actors have been performing both reliability and resilience under the umbrella of “reliability,” and the Federal Energy Regulatory Commission (FERC) and the North American Electric Reliability Corporation (NERC) have been regulating both reliability and resilience under that same umbrella.
Although many discussions of reliability and resilience focus on the bulk power system, the study, “A Customer-focused Framework for Electric System Resilience,” recommends use of a much broader framework and metrics that are focused on customers’ experiences, rather than the grid alone.
The report found broad conclusions about electric service interruptions:
- Over 90% of outages (frequency) occur due to distribution-level problems,
- Typically no more than 10% of all power outages (frequency) are due to major events.
- About half of outage durations are due to high-impact major events, and,
- Adverse weather is the primary cause of both outage frequency and duration.
Because of these findings, the authors support the notion that focusing on how to address and mitigate these common risks is more efficient than focusing on grid resilience as a whole. “Therefore, the best strategy is to figure out how to reduce the magnitude and duration of damage caused by an outage, help customers and society better survive an extended outage, and try to recover from it as quickly as possible,” the authors suggest.