Even though 2007 was Chicago-based Commonwealth Edison Co.'s most active storm year in a decade, the utility achieved impressive reliability improvements on behalf of customers. This included the duration of non-storm outages improving to the lowest level in a decade.

During 2007, the average non-storm outage lasted 76 minutes. This represented a 7 percent improvement over 2006 (82 minutes) and the lowest level achieved since 1998 when non-storm duration was 36 percent higher than today.

In terms of outage frequency, the average number of non-storm outages per customer also improved, with customers experiencing 6 percent fewer outages in 2007 than in 2006 (1.03 vs. 1.10). The 2007 number also represented a 28 percent decline since 1998.

"We are pleased with reliability performance in 2007. Nonetheless, we remain focused on producing continuous improvement in all operational areas," ComEd President and Chief Operating Officer J. Barry Mitchell said. "Not to be overlooked was how well our employees responded to the many storms last year. This included their amazing effort restoring 634,000 customers in five days following the Aug. 23 and 24 storms that left six counties declared federal disaster areas."

For its August storm restoration efforts, ComEd received the 2007 Emergency Recovery Award from the Edison Electric Institute. ComEd's northern Illinois service territory also experienced 16 other storms in 2007 that interrupted service to 10,000 or more customers for at least three hours. This was the largest number of such storms in 10 years.

Given the number and severity of storms in 2007, Mitchell said it wasn't surprising that overall outage frequency (storm and non-storm outages) increased slightly in 2007 -- going from 1.48 to 1.57 outages per customer. However, he noted this still represented a 29 percent improvement since 1998.

Last year, ComEd invested more than $250 million to increase capacity in fast-growing areas and enhance systemwide reliability. This effort included the completion of 468 jobs in preparation for the peak-load summer period, including installation of 11 new "DCs-in-a-box." This award-winning ComEd innovation contains 10-megawatt transformers within a safe, compact box to accommodate local load growth and eliminate the need for constructing a large substation.

ComEd also continually reviews its system to minimize customers' exposure to large area outages. This included completion of a number of large-scale reliability projects such as:

• Installing 127 automated switches vs. an original goal of 76. These switches allow ComEd to automatically "sectionalize" a long distribution line. In the event of a problem on the line, the switch opens and limits a service interruption to about half of the customers on the line. By splitting the circuit in two, crews can also more quickly isolate the problem and restore service. In many cases, power is automatically restored from other sources resulting in only a momentary outage.
• Replacing more than 1,500 lightning arrestors, or more than 50 percent in excess of those installed in a typical year. Lightning arrestors protect electrical equipment from surges of induced electricity generated by direct or nearby lightning strikes.
• Completing more than 90,000 preventive maintenance tasks on the system in order to prevent failures.

In addition to these and other infrastructure investments, the company performs regular maintenance work such as vegetation maintenance to protect electrical lines from tree contact, system engineering to achieve optimal equipment operations, and regular visual inspections of above-ground electrical lines -- all of which contributes to reliable electric delivery.

"Our employees take great pride fulfilling our primary mission to keep the lights on. On those occasions when an outage occurs, we make every effort to restore power as quickly and safely as possible," Mitchell said. "We will strive to provide our customers with continually higher levels of reliability through infrastructure investments and by applying the next generation of technology to our system."