Southern Energy Inc., a unit of Southern Company, has completed its $480 million purchase of 1,776 megawatts of gas, oil, coal and hydropower generation from Orange and Rockland Utilities Inc. and Consolidated Edison Inc. in New York State.

The New York State Public Service Commission approved the transaction June 24.

Southern Energy also announced today that it will seek to build an additional 750 megawatts of highly efficient natural gas-fired generation at one of the facilities it has acquired, the Bowline power plant in West Haverstraw, N.Y.

“New York State is taking a leadership role in opening its electricity market to full competition, and we look forward to participating in this dynamic new environment,” said Gale Klappa, president of Southern Energy’s North America Group. “Southern Energy intends to play an important role in helping meet the state’s need for electricity.”

Part of that role will be to provide additional electricity generation that will be needed as demand grows across New York. The new Bowline generation will consist of a steam turbine and three natural gas-fired combustion turbines.

The three combustion turbines, similar to jet engines, make electricity by burning natural gas. They also produce heat for the steam turbine, which makes additional power in a process known as combined-cycle generation.

“Our planned expansion at the Bowline facility represents the cleanest, most efficient way to produce electricity on a commercial scale,” Klappa said.

The combined-cycle generation will cost more than $390 million.

Southern Energy Inc. develops, builds, owns and operates power production and delivery facilities and provides a broad range of services to utilities and industrial companies around the world. Southern Energy supplies energy in 10 countries on four continents. Its Southern Company Energy Marketing unit provides energy trading, marketing and financial services and other energy-related commodities, products and services to customers in North America.

Southern Company (NYSE: SO), the largest producer of electricity in the United States, is also the parent firm of Alabama Power, Georgia Power, Gulf Power, Mississippi Power and Savannah Electric.