Experts Warn Coordinated Attacks Could Cause 18-Month U.S. Blackout

Experts warn that coordinated attacks on multiple U.S. electrical substations could cause a nationwide blackout lasting up to 18 months, exposing critical vulnerabilities in the aging power grid.

The warning follows a 2013 incident in which gunmen disabled 17 large transformers at a Pacific Gas and Electric substation near San Jose, California, in less than 20 minutes. Although power was rerouted to prevent a blackout, the attack revealed weaknesses in the grid’s infrastructure, which could lead to catastrophic outages if repeated on a larger scale.

Replacing damaged high-voltage transformers is a major challenge, with lead times for manufacturing and installation ranging from two to over four years under normal conditions. Some reports indicate waits up to 41 years for specialized equipment, exacerbated by limited manufacturers and supply chain constraints.

Jon Wellinghoff, former chairman of the Federal Energy Regulatory Commission (FERC), emphasized the severity of the risk.

"If attackers knocked out nine critical substations across the three interconnections, they could black out the entire United States — and such an outage could last 18 months or more," said Wellinghoff.

Wellinghoff’s analysis is based on scenarios involving simultaneous strikes across the Western, Eastern, and Texas interconnections that together form the U.S. grid. While a nationwide blackout requires coordinated disruption across these regions, it remains a feasible threat.

The 2013 Metcalf attack involved shooters targeting the cooling systems of transformers, allowing damage to spread slowly and avoid immediate alarms. The substation took nearly a month to repair, highlighting the difficulty in responding quickly to such sabotage.

Experts note that infrastructure aging compounds the problem. Over 75% of distribution transformers exceed their 50-year design life, and the average large transformer is nearly 40 years old, increasing risks of failure and replacement delays.

These vulnerabilities have prompted calls for improved grid resilience and modernization. The Canadian government is pursuing a national integrated power grid to enhance energy security and reduce reliance on cross-border electricity, which could shield its economy from disruptions.

Manitoba Premier Wab Kinew stated, "By joining this national call for a grid, we’re making sure Manitoba has the power it needs to grow, create good jobs, export more of our own clean energy east and west, and shield our economy from global uncertainty." Prime Minister Mark Carney also advocated for a robust, independent Canadian electricity grid.

The U.S. Department of Energy’s 2010 report highlighted the dire consequences of a prolonged power outage, including degradation of food, water, and fuel supplies, communication breakdowns, economic shutdown, and escalating social unrest.