A 150 MMcf/d capacity expansion of TC Energy’s Gas Transmission Northwest Express pipeline can move forward after the Federal Energy Regulatory Commission voted 2-1 in favor of the project on April 16.

The GTN Express is a 1,400-mile natural gas pipeline stretching from Canada’s southern border through Idaho, Washington and Oregon to Northern California. Its current capacity is 2.9 Bcf/d.

Canadian company TC Energy owns the pipeline and requested to upgrade its capacity through a $75 million project that would improve three pump stations along the route, according to a 2023 filing with FERC.

Environmental groups Columbia Riverkeeper and Rogue Climate filed for a stay and rehearing of the project on Nov. 21, arguing that the FERC violated the National Environmental Policy Act and the Natural Gas Act by granting approval.

The FERC action on April 16 dismissed the environmental groups’ arguments as lacking merit.

The governors of Washington, Oregon and California and the attorneys general of Washington and Oregon were also opposed to the plan. However, the states’ motions against the expansion came in after the deadline to file for a rehearing, and FERC disqualified the requests.