CHATTANOOGA (AP) — The Tennessee Valley Authority is changing its 19-year-old rate structure April 1 but can't say who among its 9 million customers will pay more.

TVA is leaving customer rate decisions to its 155 distributors that supply power in Tennessee, Alabama, Mississippi, Kentucky, Georgia, North Carolina and Virginia.

The nation's largest public utility disputes claims that the move aimed at changing power use habits mostly means higher bills for retirees who are customers of small rural distributors and don't turn down thermostats while they're away from home.

A TVA senior vice president, John Trawick, said the change in the 1992 rate structure is "revenue neutral" for TVA. He said some customers who use an average of 1,000 kilowatts monthly will pay about $3 more and some will pay $3 less, depending on how distributors pass along the cost.