The Brayton Point Power Station, New England's largest and one of its last coal-fired power plants, is seen along Mount Hope Bay in Somerset, Massachusetts, in this May 31, 2017, file photo. The plant, which began generating electricity in the 1960s, was demolished earlier this year. Credit: Matt O'Brien | AP

Utility regulators say Maine has received nearly $2.5 million in the latest auction of carbon dioxide emission allowances.

Maine is among nine New England and mid-Atlantic states that participate in the Regional Greenhouse Gas Initiative.

Those states limit, or cap, carbon dioxide emissions from power plants to reduce air pollution. Companies then purchase allowances at auctions that allow them to emit a certain amount of CO2 gas from power plants generating more than 25 megawatts of electricity.

That auction generates revenues for all nine states, which had reduced CO2 emissions by more than 50 percent since 2007.

Maine Public Utilities Commission’s administrative director said the latest auction reached the milestone of selling the one billionth emission allowance.

Maine has received $108.6 million in revenue since 2007 that has financed rate relief, energy efficiency and renewable energy projects.