A new federal appeals court ruling could raise questions over the legal viability of the narrowed downstream greenhouse gas (GHG) emissions analysis for natural gas pipeline reviews adopted by FERC under the Trump administration.

In a case challenging a December 2019 certificate order for a 72,400 Dth/d upgrade project on the Tennessee Gas Pipeline (TGP) system, the U.S. Court of Appeals for the District of Columbia Circuit remanded — but did not vacate — the Commission’s decision in a ruling late last week. The court cited flaws in the agency’s GHG analysis for the project, which involved 2.1 miles of new pipeline and a new compressor station in Agawam, MA.

In sending the certificate order back to the Federal Energy Regulatory Commission for further review, the court found that the agency had fallen short of National Environmental Policy Act requirements by not examining the downstream emissions impacts of its decision more closely.

Based on the record in the TGP upgrade project, the court concluded that “the available information was sufficiently specific to render downstream emissions reasonably foreseeable.” The court called on FERC to develop a supplemental environmental assessment “in which it must either quantify and consider the project’s downstream carbon emissions or explain in more detail why it cannot do so.”

Then-commissioner and current FERC Chairman Richard Glick dissented in the remanded certificate order, at the time lamenting that the agency had “once again” refused to “consider the consequences its actions have for climate change.”

Under Glick’s chairmanship, FERC has moved to broaden the agency’s consideration of GHG emissions impacts in its decision making for natural gas projects, but the industry has pushed back, citing potential for added regulatory uncertainty and lengthier project reviews.

In a recent Senate Energy and Natural Gas Resources Committee meeting, Glick said improving the “legal durability” of FERC’s natural gas infrastructure reviews is a key reason for moving forward with the agency’s policy revisions, including for GHG analysis.

Still, the latest court decision on the TGP upgrade project may have only limited implications for the bigger debate over how FERC considers GHG impacts in its pipeline reviews, according to analysts at ClearView Energy Partners LLC.

“We see nothing that provides any view on whether FERC has the authority to require mitigation of those emissions as a general matter,” the ClearView analysts wrote in a note to clients. “This is a question central to the commission’s recently released and controversial policy statements. In our view,” the appeals court decision “only indicates FERC should quantify them or provide a stronger explanation for why it cannot.”