FERC gave conditional approval Thursday to a request by Williams’ Transcontinental Gas Pipe Line Co. LLC (Transco) to begin its Mobile Bay South III Expansion Project, which when completed will provide an additional 225,000 Dth/d to markets in Alabama and Florida.

Transco filed its application at the Federal Energy Regulatory Commission [Docket No. CP13-523-000] last July, seeking to provide incremental firm transportation service on its Mobile Bay Lateral from supply interconnections at its Compressor Station 85 Zone 4A Pooling Point and other receipt points to interconnections with Florida Gas and Bay Gas Storage Co. Ltd. (see Daily GPI, July 23, 2013).

According to the FERC filing, Transco has specifically proposed adding a new, natural gas-fired, 20,500 hp Solar Titan 130 turbine compression unit, a compression building, and gas cooling, yard pipeline and related auxiliary equipment to its Compressor Station 85, which is located in Choctaw County, AL.

Transco has also proposed installing a 30-inch diameter pipeline to connect the existing Gulf South Scott Mountain meter station to the suction header of a new unit and existing units at Compressor Station 85. The company will also modify three existing compressor units at the station to allow for operation at higher suction and discharge pressures.

The FERC filing shows that Transco has agreed to construct a fence on the compressor station’s property, at a minimum distance of 748.6 feet from the new exhaust stack location. The company said the fence would prevent public access and increase the area on its property that could be classified as non-ambient air. FERC said the move was consistent with guidance from the U.S. Environmental Protection Agency.

Transco also agreed to a request from the U.S. Fish and Wildlife Service (FWS) to install the lowest strand of barbed wire on the fence no less than eight inches above ground level so that it poses no threat to the gopher tortoise, an animal listed by the federal government as threatened. FERC said that with this mitigation measure, the gopher tortoise is not likely to be harmed.

Transco also agreed to coordinate with FWS and the Alabama Department of Conservation and Natural Resources’ Wildlife and Freshwater Fisheries Division in case the gopher tortoise or the eastern coachwhip snake were encountered in the project area.

FERC said Transco must complete construction within 18 months and comply with all applicable regulations and environmental conditions in its order. The commission also approved Transco’s proposal to charge an incremental recourse rate for transportation on the project, with some revisions.

Last July, Transco estimated the cost of the project at $50 million. Williams has listed a proposed in service date of April 1, 2015.

Transco is a 10,200-mile pipeline system extending from South Texas to New York City with 52 compressor stations. The system has a peak design capacity of 9.8 Bcf/d, seasonal storage of 200 Bcf and serves markets in the Southeast, Mid-Atlantic and Northeast.