Appalachian Power says it is implementing an interim base rate increase for customers in Virginia. The energy company filed a request in May with the State Corporation Commission seeking approval of a nearly $208 million increase, saying it was needed to recover increased expenses for operations and environmental compliance. State regulators agreed that the rates could be implemented on an interim basis beginning Tuesday. The case is scheduled for a hearing on Wednesday. Interim rates are subject to refund pending a final decision by the SCC. Appalachian Power estimates that a residential customer using 1,000 kilowatt-hours of electricity will pay about $16 more per month under the increase.