ALLENTOWN, Pa.—One electric utility in Pennsylvania is lowering its generation rates for residential and business customers who don't shop around for alternative suppliers.

PPL Corp. said Wednesday that the new rates are effective Dec. 1. The utility said its average customer will see a savings of just below four dollars a month.

However, 21 of 41 electric suppliers competing in PPL territory have a lower "price to compare." That's according to two state websites that track residential electricity prices.

Although it's only a partial price, the "price to compare" is the state-mandated format that suppliers must use when quoting prices. The figure combines generation and transmission charges that equal two-thirds of the total bill.