On June 6, 2025, the D.C. Circuit ruled in Appalachian Voices et al. v. FERC that the Federal Energy Regulatory Commission’s (FERC) approval of an extension of the construction deadline for Mountain Valley Pipeline, LLC’s (MVP) MVP Southgate Project (the “Southgate Project”) was permissible, denying environmental groups’ petitions for review. This case potentially forecasts future judicial treatment of agency action in the aftermath of the Loper Bright v. Raimondo decision, and signals how courts may treat future challenges aimed at delaying development in light of recent curtailment of the National Environmental Policy Act (NEPA).

On June 6, 2025, the D.C. Circuit ruled in Appalachian Voices et al. v. FERC that the Federal Energy Regulatory Commission’s (FERC) approval of an extension of the construction deadline for Mountain Valley Pipeline, LLC’s (MVP) MVP Southgate Project (the “Southgate Project”) was permissible, denying environmental groups’ petitions for review. This case potentially forecasts future judicial treatment of agency action in the aftermath of the Loper Bright v. Raimondo decision, and signals how courts may treat future challenges aimed at delaying development in light of recent curtailment of the National Environmental Policy Act (NEPA).

The Southgate Project is an extension of the Mountain Valley Pipeline Mainline (the “Mainline”), a natural gas pipeline running from West Virginia to Pittsylvania County in southern Virginia. FERC issued a certificate of public convenience and necessity approving the Southgate Project in 2020, setting a project completion deadline of June 18, 2023. Because the Southgate Project was intended to function as an extension of the Mainline, authorization to begin construction was conditioned on the Mainline receiving all necessary federal permits and authorizations. Due to various legal challenges, all authorizations for the Mainline were not obtained until June 3, 2023, and FERC did not authorize MVP to resume construction on the Mainline until June 28, 2023, ten days after construction on the Southgate Project was to be completed under that section’s authorizations.

MVP had requested an extension of Southgate’s construction deadline shortly before expiration. FERC found that the Southgate Project had encountered “unavoidable circumstances” and importantly, that the analyses of market need and environmental impact that had been performed previously remained valid. The agency ultimately found good cause for the extension and approved MVP’s request. Eight environmental organizations sought review of FERC’s extension approval, arguing that both approval of the extension and FERC’s decision not to revisit the original evaluation of market need and environmental impact was arbitrary and capricious, particularly in light of proposed changes to double the Southgate Project’s capacity.

The D.C. Circuit ultimately found that FERC’s approval of the extension was proper, and in doing so offered insight into judicial review of an agency’s decision. The court began with noting that FERC’s specific expertise was “entitled to substantial deference” regarding revisiting its prior findings. From there, the court evaluated the validity of FERC’s finding of good cause for an extension, where it was persuaded that MVP’s efforts to obtain all required approvals for the Mainline met this standard. While the environmental groups argued that MVP had impermissibly abandoned pursuing necessary permits and property rights necessary to complete the Southgate Project, the court found that because completion of permitting and approvals for the Mainline were  conditions precedent to construction of the Southgate Project, MVP properly focused on obtaining Mainline approvals. It would have been impossible to comply with the Southgate Project’s construction deadline without those approvals. As such, the court found that FERC properly found good cause to grant the extension.

With regard to environmental review, the petitioners argued that FERC should have revisited its prior findings addressing demand projections, environmental impacts, and the like. The court again deferred to FERC’s finding that circumstances had not changed substantially so as to warrant reconsideration of the market value, nor had MVP petitioned FERC for significant changes to the Southgate Project that rose to a level that required supplemental NEPA analysis, as the environmental groups maintained. The court noted the proposals for capacity expansion would be appropriately handled in a separate decision and was not a question currently before it. As such, it found again that FERC had not exceeded its authority in finding good cause for the extension.

This case offers crucial insight into how courts may treat future challenges to review of agency decisions. Despite the Supreme Court’s decision in Loper Bright v. Raimondo, which expanded the judiciary’s power to review and reject interpretations of statutes adopted by federal administrative agencies, this case demonstrates the substantial level of deference still given to agency decisions and forecasts a potentially antagonistic perspective against parties seeking to delay or halt development. Judge Karen LeCraft Henderson in her concurrence wrote a scathing critique of environmental groups’ challenges to development on environmental grounds, stating that “[i]n sanctioning this system, I believe courts—ours in particular—have misinterpreted and misapplied the environmental laws. In the process, we have enabled interest groups to transform the bench into a tool to stymie any new development. It is long past time to correct our mistake.”

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