Southern Company, through its Southern Energy Inc. subsidiary, has agreed to purchase electric generating assets in New England from subsidiaries of Commonwealth Energy System and Eastern Utilities Associates for $537 million.

The power plants, with a combined generating capacity of approximately 1,260 megawatts, use natural gas and oil as their primary fuels.

“This acquisition gives Southern Energy and Southern Company Energy Marketing an excellent portfolio of power plants in New England, which will significantly benefit our trading and marketing efforts in that growing market,” said Southern Energy President Tom Boren. “These assets give us the advantages of flexibility in fuel supplies while providing excellent opportunities for cost-effective expansion of our generating capacity.”

The Commonwealth Energy subsidiaries are Cambridge Electric, Canal Electric and Commonwealth Electric. The Eastern Utilities Associates subsidiary is Montaup Electric. The sale is part of the companies’ divestiture of generating assets, which results from restructuring of the electric utility industry in New England. Southern Energy will own and operate the plants, while Southern Company Energy Marketing, which markets electricity and natural gas nationwide, will sell the output to the divesting utilities and in the open market.

Commonwealth Energy is selling Canal Unit 1 and a half-interest in Canal Unit 2 in Sandwich, Mass.; five diesel generators in Oak Bluffs and Tisbury, Mass.; Kendall Station and Kendall Jets in Cambridge, Mass.; and a 1.4 percent interest in Wyman Unit 4 in Yarmouth, Maine. Eastern Utilities is selling its half-interest in Canal Unit 2.

Southern Company (NYSE: SO), the largest producer of electricity in the United States, is the parent firm of Alabama Power, Georgia Power, Gulf Power, Mississippi Power and Savannah Electric. Based in Atlanta, Southern Company, through its Southern Energy Inc. subsidiary, supplies electricity in 10 countries on four continents. Southern Company also provides energy-related marketing, trading and technical services and Southern LINC wireless telecommunications. Its common stock is one of the 20 most widely held corporate stocks in America.

Southern Energy develops, builds, owns and operates power production and delivery facilities and provides a broad range of energy-related services to utilities and industrial companies around the world. Southern Company Energy Marketing, established in 1997 as a joint venture of Southern Company and Vastar Resources, provides energy marketing and financial services to wholesale and large retail customers throughout North America. Southern Company Energy Marketing is one of the five largest marketers of electricity and one of the 10 largest marketers of natural gas in the United States.