CHATTANOOGA, Tenn. (AP) - Tennessee Valley Authority residential customers will pay up to $8.50 more each month starting in October as the utility passes along its eighth straight increase in fuel cost.

The 6.4 percent increase in the fuel cost adjustment is the largest since August 2007 and totals 28 percent when added to monthly increases since March.

The utility's website shows that compared to September, the fuel cost adjustment will add between $4 and $8.50 to monthly residential bills, depending on amount of power used.

TVA says high temperatures in August limited power generation capabilities and demand exceeded projections by 8 percent.

The nation's largest public utility supplies power to nearly 9 million people in Tennessee, Alabama, Mississippi, Kentucky, Georgia, North Carolina and Virginia.

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