50 million - Americans in the Northeast and Midwest left in the dark after the blackout of Aug. 14, 2003
$33 milllion - Fines paid by utilities since NERÇ in 2007 stiffened penalties for problems that might lead to outages
13 - Average number of minutes a year power is interrupted in the Tennessee Valley
99.999 - Percent of reliability for power delivery by TVA in the past 13 years
16,086 - Miles of transmission lines operated by TVA
31,500 - Miles of transmission lines in the Chattanooga-based Realiability Coordinator region, which includes TVA and seven other utilities
In a bunker protected by two barbed-wire gates near the Chickamauga Dam, Joel Wise and his TVA colleagues monitor the electric grid to make sure the lights stay on across parts of a dozen states.
"We're constantly monitoring the grid for any signs of trouble and to be ready if there are power interruptions," Wise said Wednesday.
The staff and equipment inside the regional operations center in Chattanooga have been revamped and upgraded over the past decade to limit chances of a power blackout like the one that left 50 million Americans in the dark 10 years ago Wednesday.
The 2003 blackout -- the worst power outage in U.S. history -- began when a tree fell on a power line in Ohio. The power outage quickly cascaded across eight states, interrupting phone service, disrupting transportation and cutting off lights and air conditioning in the sweltering summer in eight Northeast and Midwest states and Canada.
The Tennessee Valley Authority, which serves parts of seven Southeastern states, did not lose power during the 2003 blackout. Terry Boston, the former head of TVA's transmission network who helped investigate the causes of the 2003 outage, said voltage fluctuated briefly in TVA's load center as power generation sputtered to the north. But TVA never interrupted any power in its seven-state region.
With its integrated generation and transmission network of more than 16,000 miles of power lines, TVA has maintained 99.999 percent reliable power delivery for each of the past 13 years, meaning that the typical TVA customers has had less than 13 minutes a year of power outages.
But for all its success, TVA still had to change its ways following the 2003 blackout and the subsequent rules implemented four years later by the Federal Energy Regulatory Commission.
The nonprofit North American Electric Reliability Corp., (NERC) replaced the previous voluntary standards with government-imposed penalties for utilities that threaten the integrity of the grid.
Boston said the principal faults that led to the outage a decade ago were "trees, tools and training."
In response, FERC has required transmission utilities maintain rights of way for power lines free of the threat of a falling tree or limb. TVA has since cut down any trees that might grow close to its power lines along its transmission rights of way. The policy change sparked criticisms and a lawsuit from neighbors complaining that TVA was unnecessarily clear-cutting property, but last month a federal judge in Knoxville upheld TVA's vegetation-control program. Last week, an attorney for homeowners suing TVA over the policy filed an appeal.
Wise said TVA also has upgraded employee training and installed better means of communication among utilities and power producers to better control the sources and flow of electricity across the grid.
Since NERC began imposing penalties in 2007 for utilities that risk the dependability of the U.S. electric grid, utilities have paid millions in fines for not maintaining rights of way, equipment, training or procedures mandated in the wake of the 2003 blackout. An Associated Press review of reliability penalties found utilities have paid more than $33 million since just 2010. TVA paid a $175,000 fine in 2010 when a willow tree grew to close to a 500 kilovolt line, flashed over and caused an outage. To mitigate the problem, TVA had to spend $4.5 million in 2010 and is spending an extra $2.5 million for vegetation control every year, TVA spokesman Mike Bradley.
TVA controls its own power generation and distribution from its power load center in the Chattanooga Office Complex in downtown Chattanooga. Near the Chickamauga Dam, TVA operates a regional operations center that serves as the reliability coordinator for TVA, the Associated Electric Cooperative in Missouri, Electric Energy Inc., in Joppa Inc., Louisville Gas and Electric and Kentucky Utilities, Owensboro Municipal Utilities, Memphis Power, Light Gas & Water, Alcoa Power, Smokey Mountain Transmission. The Chattanooga center is one of 14 such reliability stations in the country and operates under NERC rules to limit unplanned outages.
"We have the highest level of authority of any of the operating identities of the electric system to make sure that the system is operating reliably and we take that responsibility very seriously," he said.
Armando Rodriguez, general manager of inter regional operations at TVA, said TVA works to wheel power across its territory and buys and sells power with other power generators to meet not only its own power needs but those of the entire region.
"We all learned in 2003 that the reliability of the electric system is critical and can have a huge impact on everyone when millions of people were without power for up to four days," he said. "We want to make sure that we avoid any cascading effect of an outage like what we saw 10 years ago."
The Associated Press contributed to this report.
Contact Dave Flessner at email@example.com or 757-6340