KNOXVILLE (AP)-The electric bill is going up again in April.

The Tennessee Valley Authority is increasing its fuel adjustment charge. The utility said the hike will raise residential power bills between $3 and $6.50 per month, depending on how much electricity is used.

Higher fuel prices this year are eating into a fuel adjustment credit that TVA has applied to the rate because of lower fuel prices last year. It's from about a half cent to a fifth of a cent per kilowatt hour.

TVA says that amounts to a 5.9 percent increase in what residential customers will pay TVA for the cost of the utility buying fuel. That follows a 5.3 percent increase for March.

TVA uses fossil fuels-coal, oil and natural gas-to generate about half of its electricity. When those costs rise, TVA's costs increase.

The other half of TVA electricity comes from its nuclear plants and dams.