Williams Partners LP announced today that the Federal Energy Regulatory Commission has approved a proposal to expand its Transco natural gas pipeline to serve markets in the southeastern U.S.

New service from the Mobile Bay South II Expansion project would be available in May 2011. The project has been designed to create an additional 380,000 dekatherms per day of southbound, year-round firm transportation capacity on the Mobile Bay Lateral from Transco’s mainline at Station 85 near Butler, Ala., to its interconnect with Gulfstream Natural Gas System in Coden, Ala.

“Williams is excited to provide this economically priced link between the abundant on-shore supplies now available at Station 85 and growing markets in southern Alabama and Florida,” said Phil Wright, president of Williams’ natural gas pipeline business.

The Mobile Bay South II Expansion project will require a compression addition of 8,180 horsepower at Transco compressor station 85 and facility modifications at Station 83. Construction is scheduled to begin this month and conclude by May. Williams estimates the project facilities will cost approximately $36 million.

The Transco pipeline is a 10,000-mile pipeline system which transports natural gas to markets throughout the northeastern and southeastern U.S. The current system capacity is approximately 8.6 billion cubic feet per day.