Transcontinental Pipe Line Company LLC (Transco), a wholly-owned subsidiary of Williams Partners LP, has received US Federal Energy Regulatory Commission (FERC) approval to begin construction of the Virginia Southside Expansion Project II.
The project will involve the construction and operation of approximately 4.33 miles (7 km) of pipeline facilities, 21,830 hp (16,285 kW) of gas turbine-driven compression, 25,000 hp (18,650 kW) of electric motor-driven compression, and the construction or modification of associated aboveground and underground facilities.
Transco will modify two existing compressor stations, Station 185 and Station 166. Modifications to Station 185, located in Prince William County, Virginia, USA, will include the installation of one new electric-driven compressor unit for an additional 25,000 hp, and installation of associated buildings and ancillary facilities. Modifications at Station 166, in Pittsylvania County, Virginia, consist of the installation of two new Solar Taurus 70 gas turbines for an additional 21,830 hp. In order to do this, Transco will extend the existing Station 166 compressor building and add gas cooling, scrubbers, blowdown silencers, and associated piping and valves. Transco will install an additional generator set that will provide service to the new units in the event of a power outage. Additionally, Transco will rewheel two existing Solar Taurus 70 gas turbines.
Odorization work in North Carolina and South Carolina is necessary to address the potential for odorized gas on Transco’s mainline to migrate in a southerly direction to points on Transco’s system that are currently not capable of handling odorized gas. As Transco experiences increased gas flows from north to south, the null point on Transco’s mainline shifts farther south. Because of this, Transco will modify one existing compressor station (Station 140), 11 existing meter and regulator (M&R) stations, six existing valve settings, and one drip bottle site, all located on its existing mainlines and Tryon Lateral in North Carolina and South Carolina. Modifications to the existing M&R stations will include the construction of a new building at each site to house equipment necessary for supplemental odorization. Additionally, work at six of the existing M&R stations (Mill Springs, West Startex, Moore, Startex, Spartanburg, and South Union M&R stations) will include the replacement of a total of five below ground condensate tanks (the Startex and Moore M&R Stations share a condensate tank) with a new aboveground condensate tank. Modifications at the existing Station 140 in Spartanburg County, South Carolina, as well as the existing valve settings and the existing drip bottles, will consist of installation of equipment necessary for odor masking of all normal operation atmospheric vents.
The project, with an in-service date of December 1, 2017, will enable Transco to provide 250,000 dekatherms/day of incremental firm transportation service to Virginia Power. The project capacity is designed to serve 100% of the gas requirements of Virginia Power’s proposed 1580 MW, combined-cycle, natural gas-fired power station in Greensville County, Virginia.