A Central Maine Power truck in Windham in June 2019. Credit: Lori Valigra / BDN

Residential and business customers of Central Maine Power will pay lower rates for their electricity supply in 2021, a state regulatory agency said Wednesday.

The lower rates, announced by the Maine Public Utilities Commission, resulted from the agency’s competitive bidding process for standard offer prices, a default rate for those who do not buy electricity from a third party.

The decrease would amount to almost a 12 percent reduction in the supply portion for residential and small business customers and a 5.1 percent reduction in a total residential customer bill for a home averaging 550 kilowatt hours of use monthly. The monthly savings is $4.70 or $56.38 annually. A monthly bill of $91.38 would decrease to $86.68 per month.

The decrease comes a day after the commission announced lower standard offer rates for Versant Power, the state’s other major utility formerly known as Emera Maine. The changes reflect supply and demand conditions in New England and their impact on energy markets.

CMP’s medium-sized businesses will see an average decrease of 12 percent in the supply portion of their bill, meaning a business using 20,000 kilowatt hours a month will save about $2,000 annually.

The company has about 630,000 customers in central and southern Maine. The standard offer price accounts for approximately 50 percent of sales in CMP’s service area and about 40 percent of customer bills.

Medium-sized businesses using CMP will see varying monthly prices averaging 6.16 cents per kilowatt hour. They will see an average 12 percent decrease annually in the supply portion of their bill.

Prices for CMP’s large-business customers will be indexed to market prices and set in advance of each month. The names of the suppliers selected for CMP will be released in two weeks when the power supply arrangements are finalized.