PORTLAND, Maine — Most power customers in Emera Maine’s Bangor Hydro district will see the unit price of electricity drop next year, while Central Maine Power customers will pay more.

The Maine Public Utilities Commission this week approved new standard rates for electricity service, or the energy supply portion of customer bills. For Emera Maine’s Bangor Hydro District, the standard residential rate will drop 4.6 percent, to 6.32 cents per kilowatt-hour.

Central Maine Power customers in the southern, central and western parts of the state will see prices rise about 3.5 percent, to 6.69 cents per kilowatt-hour.

For the average home, using about 550 kilowatt-hours per month, the savings for Emera Maine’s Bangor Hydro customers is about $1.67 per month, compared with the annual average price for 2016. The increase for CMP customers will be about $1.25 cents per month.

The Maine Public Utilities Commission disclosed the prices but not yet the suppliers and did not elaborate on why prices for residential customers differed across the state’s two major utility service areas.

Central Maine Power’s service territory represents a much larger base of about 609,500 residential customers. Emera Maine’s Bangor Hydro District has about 123,000 customers, as of the latest figures from April.

The vast majority of those customers pay the price set by the state this week. Others pay for power through “competitive electricity providers,” which have operated in the state since 2012. A Bangor Daily News investigation found those competitive suppliers have cost Mainers about $50 million more than if those customers had received standard offer service during that time.

Prices for small commercial customers will go down slightly in each area, though prices fluctuate from month to month, from about 4.7 cents per kilowatt-hour to shy of 9 cents per kilowatt-hour throughout the year.

The price changes released this week reflect only one portion of a customer’s bill, which also includes costs for power delivery. Those delivery rates, which cover utilities’ costs for maintaining the grid, have been rising in Maine and throughout the region.

Darren is a Portland-based reporter for the Bangor Daily News writing about the Maine economy and business. He's interested in putting economic data in context and finding the stories behind the numbers.