The Hillabee expansion project will increase the capacity of the existing Transcontinental gas pipeline (Transco pipeline) by 1.13 billion cubic feet (bcf) per day, which will be supplied to the Sabal Trail pipeline.

The project is being built in three phases by Williams Companies. It is part of the Southeast Market Pipelines (SMP) project, which aims to meet the growing natural gas needs of markets in Florida and Southeast US.

Approved by the Federal Energy Regulatory Commission (FERC) in 2016, the SMP project includes the separate but connected Hillabee expansion project, the 832km Sabal Trail pipeline and 202km Florida Southeast Connection project as well as associated facilities such as compressor stations, valves, and inspection equipment.

The first phase of the Hillabee expansion project was commissioned in July 2017, while phase two became operational in May 2020. The last phase of the project is expected to be in service by the second quarter of 2021.

The pipeline will meet the energy needs of approximately four million American homes when operating at full capacity.

Hillabee expansion project details

The Hillabee expansion project includes the construction of eight new looped sections with varying diameters of 42in-48in in Alabama. The overall compression capacity of the project will be 88,500 horsepower (hp).

The project will add an aggregate length of 70km to the Transco pipeline, which is operated by Williams’ subsidiary Transcontinental Gas Pipe Line (Transco).

Phase one of Hillabee expansion project

The first phase of the project included the installation of the 8.52km-long Proctor Creek Loop and 4.18km-long, Hissop Loop with a diameter 42in in Coosa County. The 12km-long, 42in diameter Alexander City Loop in Tallapoosa County and the 7.56km-long, 48in diameter Billingsley Loop in Autauga and Chilton Counties were also built.

A new compressor facility was built in Choctaw County and a new 20,500hp compressor unit was added to Compressor Station No. 105 in Coosa County. Further, modifications were made to existing compressor stations and valve sites.

The first phase increased the Transco pipeline’s capacity to 818 million cubic feet (mcf) per day. It enabled the pipeline to supply natural gas to power generating facilities located in Florida through the Sabal Trail pipeline.

Hillabee expansion project phase two

The second phase of the project included the installation of two 42in diameter loops including the 10.78km-long Rock Springs Loop in Choctaw County, and the 6.27km-long Verbena Loop in Chilton County.

A new 16,000hp compressor unit was installed at Compressor Station 95 in Dallas County, Alabama. The Compressor Station 100 was uprated from 42,000hp to 46,000hp. In addition, related underground and aboveground facilities were constructed.

The second phase added a capacity of 206mcf per day to the Transco pipeline.

Phase three details

The phase three of Hillabee expansion project will include the installation of two 42in diameter loops including the 8.53km-long Butler Loop in Choctaw County and the 12km-long Autauga Loop in Autauga and Chilton Counties.

Further, the Compressor Station 100 in Chilton County will be upgraded and additional infrastructure will be built.

Contractors involved

Cardno, an infrastructure and environmental services company, performed environmental field surveys and provided environmental project management. It also provided support for the filing of the permit and application development.

Hunt, Guillot & Associates, a program management and engineering company, was contracted for the installation of the compressor stations 95, 100 and 85.

Transco pipeline details

The 16,900km-long Transco pipeline is one of the largest-volume interstate pipelines in the US. It serves customers in Texas, Georgia, North Carolina, New York, New Jersey and Pennsylvania.

The pipeline’s end users include residential, commercial, industrial, and electric generation operators.