Blackout left New York skyscrapers dark at sundown. (Photo by Tom Sawyer for ENR)

In an initial report completed by the U.S.-Canada Power System Outage Task Force, officials found that employees of FirstEnergy Corp., Akron., were not aware of problems with three high-voltage transmission lines until the problem escalated out of control. When tree limbs caused those transmission lines to short circuit, the control room alarm system failed to react. Because FirstEnergy’s monitoring system was not providing current information about problems, the control room operators took no action.

This set off a chain reaction because neighboring utilities and reliability coordinators, who could have addressed the growing problem, were not informed. The report also found that the Midwest Independent System Operator, which coordinates power transmission in the region, also was performing ineffectively.

Although the study makes no recommendations, the task force concluded that "this blackout was largely preventable," U.S. Energy Secretary Spencer Abraham said.

Investigators also found that MISO was using outdated data to support real-time monitoring, which hindered it in detecting further problems and assisting in relief action. Other contributing factors were poor communications, human error, mechanical breakdowns, inadequate training, software glitches and insufficient attention to issues ranging from the performance of sophisticated computer modeling systems to simple tree trimming, according to Abraham.

FirstEnergy President and COO Anthony J. Alexander asserts, "We remain convinced that the outage cannot be explained by events on any one utility system." The report does not adequately address the underlying causes of the outage, says Alexander.

Task force officials now begin the second stage of their report. Officials will conduct public forums in the affected areas of the two countries where comments on the initial findings will be solicited. A final report is expected to include specific recommendations.