AUGUSTA – Rates paid by most residential and small-business customers of Central Maine Power and Bangor Hydro-Electric Co. will be going up by 2.5 to 3 percent, effective March 1.

State regulators announced the increase after accepting bids Wednesday on new standard offer energy prices.

Those higher prices will be offset in part by a reduction in delivery rates linked to lower “stranded costs” that reflect long-term expenses incurred before the electric utility market was restructured in 2001.

Public Utilities Commission Chairman Kurt Adams said the panel accepted standard offer bids for only a year because of the uncertainties surrounding a longer contract.

The bids account for one-third of the load for standard offer customers. When combined with prices from previous years, energy costs will be about 9.97 cents per kilowatt-hour for CMP customers and about 10.05 cents for those of Bangor Hydro.

Standard offer power accounts for about 99 percent of the electric load for residential customers of the two utilities.

CMP said savings to its customers resulting from its declining stranded-cost expenses would total nearly $175 million over three years.