FERC has denied a request from three environmental groups to rehear a 2017 order authorizing the Mountaineer XPress and Gulf XPress projects, a pair of TransCanada Corp. efforts to increase natural gas pipeline capacity out of the Appalachian Basin by expanding the company’s Columbia Gas Transmission LLC’s system.

The decision comes more than a year after the Federal Energy Regulatory Commission authorized partial service to begin on Columbia Gas Transmission LLC’s (TCO) Mountaineer Xpress project [CP16-357]. Mountaineer XPress was designed to add 164.5 miles of 36-inch diameter pipe and the six miles of 24-inch line, expanding the TCO system by adding 2.7 Bcf/d.

The Gulf XPress project was to add seven new compressor stations — three in Kentucky, two in Tennessee and two in Mississippi — to expand the capacity of Columbia Gulf Transmission LLC’s system [CP16-361]. The project would also include upgrades to an existing compressor in Carter County, KY, and an existing meter station in Boyd County, KY.

FERC issued certificates of public convenience and necessity for the Mountaineer XPress and Gulf XPress projects in late 2017. Within weeks, Allegheny Defense Project, Ohio Valley Environmental Coalition and Sierra Club file for rehearing. FERC should revisit the decision, the environmental groups said, because both it and the project’s environmental impact study failed to comply with the Natural Gas Act and the National Environmental Policy Act (NEPA).

Among their complaints, the groups argued that FERC attempted to “obscure the significance” of downstream greenhouse gas (GHG) emissions by analyzing them at too broad a scale.

“We disagree,” FERC said in its order. “The Commission’s environmental review went beyond what is required to comply with NEPA by estimating GHG emissions emitted by downstream consumption of natural gas, an activity that is attenuated and not reasonably foreseeable.”

FERC’s analysis of downstream emissions, a bone of contention between Commissioners for months, was argued again in the Mountaineer rehearing order. Chairman Neil Chatterjee and Commissioner Bernard McNamee supported the decision not to revisit the case, while Commissioner Richard Glick dissented.

“Today’s order on rehearing is not the product of reasoned decisionmaking,” Glick wrote in a dissent attached to the order. “Its analysis of the project’s contribution to climate change is shoddy and its conclusion that the projects will not have any significant environmental impacts is illogical. After all, the Commission itself acknowledges that the projects will contribute to climate change, but refuses to consider whether that contribution might be significant before proclaiming that the projects will have no significant environmental impacts.”