TVA Keeps Power On 99.999 Percent of the Time

Nov. 18, 2009

For the 10th consecutive year, TVA has provided reliable power 99.999 percent of the time to its customers in the Tennessee Valley.

“The consistency of providing this service is what’s important,” said TVA Vice President of Transmission Operations and Maintenance Tracy Flippo. “It means we’re doing all we can to make sure the power is there when our customers need it.”

The reliability figure is TVA’s measurement of the magnitude and duration of power outages that affect local power distributors and the industries served by TVA across the Valley over a 12-month period that ended Oct 1.

“It means responding to emergencies in the middle of the night and doing what’s needed to get the power back up,” Flippo said. “Reliability is our No. 1 one customer goal.”

TVA owns and operates one of the largest transmission systems in North America, with nearly 16,000 miles of transmission lines and 500 power stations and switchyards in seven states.

The performance record can be attributed, in part, to TVA’s $1.1 billion investment in its transmission system since 2000, according to TVA Vice President of Transmission and Reliability Bob Dalrymple.

“We developed a plan to replace equipment, from poles and wires to entire stations and followed that with a strategy to maintain the system that continues today,” he said.

But even at 99.999 percent, Flippo said it’s not possible to be perfect. He said something is likely to happen that causes an outage somewhere in the system during the course of a year.

“The weather is our worst enemy,” said Flippo. “It only takes one bolt of lightning to affect the system.”

Dalrymple said the key is quick response when things happen. “There are many things we can do, including rerouting service around the affected area, to restore power within minutes,” he said.

TVA is the nation’s largest public power provider and is completely self-financing. TVA provides power to large industries and 158 power distributors that serve approximately 9 million consumers in seven southeastern states. TVA also creates economic development opportunities and manages the Tennessee River and its tributaries to provide multiple benefits, including flood damage reduction, navigation, water quality and recreation.

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