The Atlantic Sunrise pipeline project is an expansion of the existing Transco natural gas pipeline. It has been designed to supply an additional 1.7 billion cubic feet per day of natural gas from the rich Marcellus gas supplies in Pennsylvania to the Mid-Atlantic and Southeastern US markets.

While the pipeline project is slated for mechanical completion starting in August 2018, it is expected to enter full service in the second half of next month, subject to timely receipt of the remaining regulatory clearances.

The company said that the mechanical completion date will be subject to current contractor schedules and will also depend on weather conditions.

Williams Partners revealed that a segment of the mainline component of the project, delivering 550 million cubic feet per day of natural gas, has been already placed into service.

The Oklahoma-based midstream company began construction on the Pennsylvania part of the Atlantic Sunrise pipeline project in last September following an approval from the Federal Energy Regulatory Commission (FERC) in February 2017.

The project has seen the installation of around 322km of large diameter pipeline, two greenfield compressor stations and also compressor station modifications across five states.

The new compressor stations are the 30,000-horsepower facility in Wyoming County named as Compressor Station 605 and the 40,000-horsepower facility named Compressor Station 610 in Orange Township.

In Pennsylvania, nearly 298km of new natural gas pipeline has been laid along with about 18km of pipeline looping. The Atlantic Sunrise pipeline project also involves 4km of pipeline replacements in Virginia and associated equipment and facilities.

Overall, the pipeline construction is made up of eight different construction spreads with six of them to operate simultaneously across eight counties of Pennsylvania.

The Pennsylvania portion of the Atlantic Sunrise pipeline project, which has been named as the Central Penn Line will be co-owned by Transco and a third party.