The fuel and purchased power costs are direct pass through expenses incurred by the UC to produce your electricity. Fuel and purchased power costs are the largest single variable expense for electric utilities and they can vary greatly on the basis of supply and demand, and other market factors. Under utility regulations, any variance of these expenses collected through the base rates are passed along to customers through a charge on their bill commonly referred to as a "fuel adjustment fee." As a result of the 2021 Rate Study, the fuel adjustment fee is currently a credit (not a charge) to customers. The fuel adjustment fee will be reviewed annually and updated accordingly.