Construction on Williams' MountainWest Overthrust Pipeline Expansion Continues

The MountainWest Overthrust Pipeline (System Map) has started construction on its 325,000 Dth/d westbound expansion from Wamsutter to Opal (NWP Rockies). Once completed, the pipeline will boost east to west flow capacity across the Rockies to the premium Opal hub to further serve the West Coast markets. We expect the additional supply moving west to tighten the basis spread between CIG and NWP Rockies.

The pipeline, owned by Williams, received FERC authorization to begin construction at the end of January with early work focused on the Rock Springs Compressor Station. Following work on the ML 116 segment between June 9-11, no major work is scheduled until September. According to the maintenance schedule, shown below, there will be work at Wamsutter between September 4-9. Capacity at MAP 10827 should be reduced by 51% to 330,000 Dth/d while work is ongoing.

Maintenance schedule: https://www.mwpipe.com/MaintConstructionSchedule/MWOP

In its most recent quarterly earning call, Williams still guides for the project’s completion in 4Q25.