Mainers will see their monthly electricity supply costs jump $12 to $16 on average come January.

Regulators approved new rates this week for the standard offer, one of several components of monthly power bills. It reflects the cost of generating power and represents about 40% of CMP customers’ and 50% of Versant Power customers’ monthly bills, according to the Maine Public Utilities Commission.

The average CMP residential customer using 550 kilowatt-hours per month will see an increase of about $12 per month, with the rate jumping from 10.61 cents per kWh to 12.72 cents.

Meanwhile, an average Versant Power residential customer in the Bangor Hydro District using 500 kWh will see about a $12 increase. The standard offer rate in that district is going from 10.56 cents per kWh to 12.95 cents.

Those in Versant’s Maine Public District using the same amount of power will see a roughly $16 increase per month, with the rate going from 11.65 cents per kWh to 14.87 cents.

Electric rates are on the rise across the country. Maine electric utilities do not set rates for electric supply themselves and instead bill that cost on behalf of the supplier.

“We recognize that rising energy costs create real challenges for Maine households and businesses,” PUC Chair Philip L. Bartlett II said in a news release Wednesday. “The Standard Offer reflects current market realities and the Commission remains committed to securing the lowest reasonable prices for Maine electric utility customers in a challenging energy environment.”

The standard offer increases in Maine are largely due to the rising price of wholesale natural gas, the acting head of the Maine Department of Energy Resources said.

“This dependence on fuels that are directly tied to global markets continues to subject Maine families and businesses to volatile energy costs,” acting Commissioner Dan Burgess said in a written statement Wednesday. “Affordability remains a top priority for the Department as we work to advance initiatives to address this urgent challenge by expanding energy efficiency, ensuring ratepayer investments are carefully considered, and expanding responsible clean energy production to help stabilize costs.”

The standard offer increases are not directly related to a controversial five-year CMP plan that regulators struck down earlier this week.

When state laws changed around 2000 and the utilities industry was restructured, utilities were required to sell their electricity-generating assets and no longer supplied that energy themselves. Customers are now given the option of using a supplier of their choosing or going with the default standard offer. Most use the standard offer.

CMP said the coming rate increase is “a direct consequence” of that change 25 years ago.

“In reality, it has fragmented responsibility and introduced volatility, leaving consumers exposed to price swings and utilities with fewer tools (to) help customers manage costs,” the utility said in a written statement Wednesday.

Spokespeople for Versant Power did not immediately respond to a request for comment Wednesday afternoon.

CMP has about 650,000 to 670,000 electric customers, primarily in southern and central Maine, while Versant serves about 165,000 customers in northern and eastern Maine.