American Electric Power is planning to cut rates for most residential customers by more than 12 percent. A typical household bill would be 12.6 percent less than under current rates under a plan submitted by the utility. That's based on forecasts of market conditions next year, when the plan would take effect. A trial-like regulatory hearing process to implement the cut begins next week. The Public Utilities Commission of Ohio will issue a ruling later this year, and the plan would take effect in June 2015. The rate would fall because AEP will be buying power through an auction process in which power-plant operators compete to offer the lowest price.