MountainWest Overthrust Westbound Compression Expansion


The proposed project increases capacity to Opal, a major regional natural gas hub in Wyoming. This allows for additional gas production to meet growing regional and West Coast demand. This project will be regulated by the Federal Energy Regulatory Commission (FERC) under the 7 (c) application filing process to ensure thorough consultation and cooperation with other state, local and federal regulatory agencies, and community stakeholders.

Once approved by FERC, the expansion project will add a total of approximately 325M dekatherms per day (Dth/d) of pipeline capacity to the MountainWest system by the fourth-quarter of 2025.


Williams owns and operates a variety of energy infrastructure in Wyoming, providing our customers with safe and reliable natural gas gathering pipelines, process facilities, natural gas liquid (NGL) pipelines, natural gas transmission pipelines and storage facilities.

With over 5,192 miles of total pipeline in Wyoming, Williams’ infrastructure includes the Northwest Pipeline, Overland Pass Pipeline, Mountainwest Pipeline, White River Hub and gathering and processing operations.

Construction Activities

The project includes new equipment, modifications and upgrades to existing compressor stations.

Scope of Work

  • Rock Springs: Installing additional compression horsepower
  • Point of Rocks: Installing additional compression horsepower
  • KRGT Interconnect: New interconnect with Kern River Gas Transmission near existing facilities; KRGT will design and build new facilities
  • Ancillary Scope: Various upgrades to existing facilities and expansion of the Wamsutter meter station to accommodate additional gas volume

[2023 Q3] – Initial Public Outreach

[2023 Q4] – Target FERC 7 (c) Application

[2025 Q2] – Target Construction Start

[2025 Q4] – Target In-Service Date


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Information regarding the project can be found at

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