Williams has asked FERC to authorize an expansion of its MountainWest Overthrust Pipeline LLC system to natural gas customers in the West.

The midstream giant said it wants to add 325,000 Dth/d of westbound firm capacity to its Overthrust system by early December 2025. Supply would be delivered to southwestern Wyoming, according to an application filed with the Federal Energy Regulatory Commission. 

New capacity would flow from two points in Wyoming: 320,000 Dth/d from Tallgrass Energy Partners LP’s Rockies Express Pipeline LLC (REX) at Wamsutter, and 5,000 Dth/d from Kinder Morgan Inc.’s Wyoming Interstate Co. (WIC) near Rock Springs. The project cost is estimated at around $119.6 million, Overthrust stated.

The westward flows would run to a new interconnect with the