Appalachian Power and Wheeling Power have requested a $297 million rate adjustment that would add $18.41 a month to the average bill of a residential customer. Appalachian Power said the rate hike request was submitted Tuesday to the West Virginia Public Service Commission. The companies want an adjustment in the ENEC rate, which reimburses them on a dollar-for-dollar basis for coal and natural gas to fuel power plants and for purchased power. Currently, the monthly bill for a residential customer using 1,000 kilowatt-hours is $155.66. If approved as filed, the adjustment would add $18.41 to that amount beginning Sept. 1, the company said in a news release. Kanawha County commissioners are objecting to the rate increase request.