The Sierra Club Grand Canyon Chapter delivered roughly 2,000 public comments to Arizona Governor Katie Hobbs’s office on Friday, all originally filed with the Federal Energy Regulatory Commission in opposition to the Desert Southwest Pipeline – a signal that organized resistance to new gas infrastructure in the Southwest has reached a scale FERC cannot ignore as it weighs certification.
What the Desert Southwest Pipeline Is and Where It Stands
The Desert Southwest Pipeline is a proposed interstate natural gas transmission project designed to move Permian Basin supply westward across southern New Mexico and Arizona toward California markets and growing demand centers in the Phoenix and Tucson metros. The project’s backers – a consortium led by Kinder Morgan’s El Paso Natural Gas and Sempra Infrastructure – filed a certificate application with FERC in late 2024 under Section 7(c) of the Natural Gas Act, targeting a 2027 in-service date for the first phase of roughly 300 miles of 36-inch pipe.
FERC accepted the application for filing in January 2025 and issued a notice of schedule that set the draft environmental impact statement (EIS) for mid-2025, with a final EIS and commission decision originally slated for early 2026. That timeline has already slipped; the draft EIS was published in July 2025, and the comment period closed August 8 – the window that generated the 2,000 submissions now handed to Hobbs. The pipeline would interconnect with existing El Paso Natural Gas and Transwestern systems near the Arizona-New Mexico border and terminate at a new compressor station complex south of Phoenix, with lateral taps proposed for Tucson Electric Power’s gas-fired fleet and a planned data-center campus in Goodyear.
Opponents argue the project locks in decades of methane leakage and carbon emissions at a moment when Arizona’s major utilities – APS and TEP – have committed to 100% clean energy by 2050 and 2032 respectively. The Sierra Club’s comment packet emphasizes cumulative climate impact, water use in the Sonoran Desert aquifer, and disproportionate siting of compressor stations near tribal communities and colonias along the route. FERC’s draft EIS acknowledged “significant and unavoidable” impacts on greenhouse gas emissions but concluded mitigation measures and the project’s role in “energy reliability” justified approval with conditions.
Why This Fits a National Pattern of Gas-Buildout Friction
That points to a broader dynamic: FERC’s current majority continues to apply a “public convenience and necessity” test that weighs projected demand against environmental cost, but the demand forecasts underpinning Desert Southwest rely on gas-fired generation growth that many integrated resource plans (IRPs) in the region no longer show. APS’s 2024 IRP, filed with the Arizona Corporation Commission, models only 400 MW of new gas capacity through 2035 – down from 1.2 GW in its 2021 plan – while TEP’s latest IRP adds zero new gas after 2026. If those utility plans hold, the pipeline’s contracted capacity of 1.2 Bcf/d would face utilization rates below 40% within a decade, a threshold that in other jurisdictions has triggered stranded-asset risk reviews.
By comparison, the Mountain Valley Pipeline’s recent certification – after years of litigation and congressional intervention – rested on demonstrated LNG export demand and firm contracts with Southeast utilities still building gas fleets. Desert Southwest lacks equivalent anchor tenants; its precedent agreements are largely precedent agreements with the project sponsors’ own affiliates and a handful of Arizona distributors seeking supply diversity, not new load. That makes the project more analogous to the cancelled PennEast or Constitution pipelines – projects that cleared FERC but collapsed when state permits and market need evaporated.
If this trend holds, the 2,000 comments represent more than procedural noise; they document a record FERC must address in its final order. The commission’s 2022 policy statement on greenhouse gas considerations – still in effect despite Republican commissioner objections – requires a “downstream emissions” analysis for projects exceeding 100,000 metric tons CO2e annually. Desert Southwest’s draft EIS estimates 4.3 million metric tons from combustion alone, putting it squarely in that category. How FERC reconciles that figure with Arizona’s statutory clean-energy targets will set precedent for the half-dozen other Southwest gas projects in pre-filing.
Who This Affects
- Utility resource planners: APS and TEP must now justify any future gas capacity additions in their 2026 IRP updates against a public record showing deep local opposition and questionable need – strengthening the case for accelerated storage and long-duration solar-plus-storage procurements instead.
- Pipeline developers and midstream investors: The comment volume raises the probability of FERC imposing stringent mitigation conditions – potentially including methane leak detection and repair (LDAR) programs exceeding EPA Subpart W – that could add $150-250 million to project capex and extend the timeline by 12-18 months.
- State energy offices and governors: Hobbs’s office now holds a documented constituency opposing the project; her administration’s response – whether to intervene at FERC, deny state water permits, or stay neutral – will signal how Democratic governors in purple states navigate federal gas infrastructure they cannot directly block.
- Tribal nations and environmental justice advocates: The San Carlos Apache Nation and Tohono O’odham Nation have filed separate motions to intervene citing cultural resource impacts; the comment delivery amplifies their leverage in any future Section 106 consultation or NEPA litigation.
What to Watch Next
- FERC’s final EIS and order issuance – currently projected for Q1 2026; any dissenting opinion from Commissioner Clements or a future Democratic appointee could foreshadow rehearing requests.
- Arizona Department of Environmental Quality (ADEQ) 401 water quality certification – the state’s sole direct veto point; a denial would force FERC to either override (inviting litigation) or accept project modification.
- APS and TEP 2026 IRP filings – if both utilities further reduce gas capacity forecasts, the pipeline’s economic rationale weakens materially.
- Potential congressional rider – Mountain Valley’s precedent makes a Desert Southwest legislative fix plausible in a must-pass spending bill if FERC delays extend past mid-2026.
Bottom line: The 2,000 comments delivered to Hobbs are not just a protest tally – they create an administrative record that makes it materially harder for FERC to certify Desert Southwest without confronting the mismatch between the project’s contracted capacity and the Southwest’s actual decarbonization trajectory.
Read the full report at CleanTechnica
Note: facts and figures attributed above to reflect that outlet's original reporting. Broader context, cross-sector connections, and forward-looking scenarios reflect independent analysis by our editorial team.
About this article: Drafted by Energy Ai with AI-assisted research and writing based on public reporting, then reviewed under our editorial process before publication.
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