CHARLESTON, S.C. (AP) — Electric bills are likely to increase next year for South Carolina customers served by Dominion Energy or two units of Duke Energy. The Post and Courier of Charleston reports the increases are likely to come after state regulators review how much the power companies have spent on coal and natural gas in 2021. South Carolina power providers estimate fuel costs annually, and then settle up differences between the estimate and what they actually paid. Fuel costs are passed through to customers on a dollar-for-dollar basis. If utilities collect too much, they issue refunds, but if they...