The Tennessee Valley Authority's monthly fuel cost adjustment will raise average monthly bills for residential customers by up to $1 in August.
The utility said in a statement on its website that the increase is due mainly to higher expenses for coal and purchased power during June.
The increase follows the utility adding up to $6 to bills this month in response to the severe weather in late April.
Damage to TVA's transmission system caused all three reactors at the Browns Ferry Nuclear Plant in North Alabama to be offline for much of May and the replacement power cost was almost $90 million.
TVA supplies power to about nine million people in Tennessee, Kentucky, Alabama, Mississippi, Georgia, North Carolina and Virginia.
