Utilities in the Southeast are rebuilding the electricity grid after deadly tornadoes and storms damaged powerplants as well as transmission and distribution lines.

Photo: Courtesy TVA

TVA crews scramble to restore more than 90 transmission lines that were knocked down.

The National Oceanic and Atmospheric Administration reports that 226 tornadoes touched down between April 27 and April 28, leaving a swath of destruction and 334 dead. Hardest hit within the energy infrastructure system were utilities in Tennessee, northern Alabama, Georgia and Mississippi.

The Tennessee Valley Authority alone has 4,000 employees and contractors working on repairs. By May 3, TVA crews restored power to 95% of the 850,000 customers left without power and re-established 120 of the 128 connections to the agency's local power providers.

TVA estimated that most of the power would be restored by May 6.

The violent storms damaged more than 300 transmission poles or steel support structures, and more than 90 transmission lines were knocked down. Much of the damage was to a major 500-kV line as well as 161-kV lines serving northern Alabama and Mississippi.

Michael Keith Bradley, a spokesman for TVA, said the federal power agency is still assessing the damage.

The storm also damaged the switchyard at TVA's Widows Creek, a 1,623-MW coal-fired plant in northeast Alabama. Damage forced the utility to shut down seven of the plant's eight units.

During the storm, TVA's Browns Ferry nuclear plant in northern Alabama lost alternating-current power, but the agency was able to put the unit into cold shutdown using seven of its eight on-site diesel generators. TVA gave a “notification of unusual event,” the lowest of four levels of nuclear-plant emergency classifications. By May 2, transmission lines had been reconnected to the plant, which was no longer in emergency shutdown.

Alabama Power said that it would have power restored to 99.9% of its customers by the end of the day on May 4. The utility marshalled crews from 18 states to work on system restoration. A repair schedule survey found that more than 5,200 poles and 400 transmission structures were broken or damaged. Additionally, more than 300 substations lost power, and six substations were either destroyed or suffered significant damage.

“We're going to continue working until we bring service to everyone who can take it,” said Charles McCrary, Alabama Power president and CEO.