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Register entry No. 0013Environmental review90 FR 52932; Docket No. CP26-14-000

FERC staff issues environmental assessment for Mountain Valley Pipeline Boost compression project, Docket CP26-14-000

The assessment finds no significant impact from 265,750 horsepower of added compression in West Virginia and Virginia and recommends 13 conditions. Comments are due September 8, while Virginia's air permit for the new Swann station has not been issued.

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Summary

The staff of the Federal Energy Regulatory Commission has issued an environmental assessment for Mountain Valley Pipeline, LLC’s Mountain Valley Pipeline Boost Project, Docket No. CP26-14-000, and concluded that approving it “would not constitute a major federal action significantly affecting the quality of the human environment” [1]. The assessment was issued August 7, 2026, and its notice of availability was published in the Federal Register on August 12 at 91 FR 52048, with comments due September 8 [1, 2]. The project is proposed under section 7(c) of the Natural Gas Act and would add about 600,000 dekatherms per day of firm service on the existing Mountain Valley mainline [1].

What the record shows

The project is compression, not new pipe. Mountain Valley would add turbines at three existing compressor stations in West Virginia and build one new station in Virginia [1]:

  • Bradshaw station, Wetzel County, W.Va.: one turbine, adding 23,470 horsepower [1].
  • Harris station, Braxton County, W.Va.: one turbine and restaging of two existing units, adding 52,500 horsepower [1].
  • Stallworth station, Fayette County, W.Va.: two new turbines and upgrades to two existing ones, adding 52,880 horsepower [1].
  • Swann station, Montgomery County, Va.: a new station with three turbines totaling 136,900 horsepower, 0.2 mile of 42-inch suction and discharge piping, a pig launcher and receiver and a mainline valve [1].

Together that is 265,750 horsepower of added compression [1]. Mountain Valley says the gas would move from interconnections with Equitrans at Mobley Run and EQM Gathering at Great Hammerhead to delivery points on the Mountain Valley mainline and Southgate systems [1].

The assessment puts total land disturbance at about 65.3 acres, of which 42.4 acres would be kept for operation [1]. The scoping notice in November 2025 had described about 43.3 acres of disturbance; the assessment’s figure includes 21.6 acres of temporary laydown yards, previously used to build the mainline [1, 4].

On air quality, the table of operating emissions shows the new equipment adding about 166 tons a year of nitrogen oxides across the four stations and about 1.08 million tons of CO2e [1]. Staff found each station below the 250-ton threshold for Prevention of Significant Deterioration permitting and found that modeled concentrations, including background, stay under the national ambient standards [1]. At Swann, for example, modeled annual PM2.5 is 7.73 micrograms per cubic meter against a standard of 9 [1]. The Swann turbines would carry selective catalytic reduction and oxidation catalysts [1].

On noise, the assessment projects increases of 0.4 to 3.2 decibels at the five nearest homes and other noise-sensitive areas around Swann, with the highest projected level at 52.3 dBA Ldn, under FERC’s 55 dBA limit [1].

On climate, staff disclosed the emissions but said it “is not characterizing the Project’s GHG emissions as significant or insignificant,” citing the lack of an accepted method or threshold [1]. It compared operating emissions with 2024 state inventories: 0.66 percent of West Virginia’s and 0.51 percent of Virginia’s [1]. Downstream combustion is excluded, with a citation to the Supreme Court’s 2025 decision in Seven County Infrastructure Coalition v. Eagle County [1].

Staff recommended 13 conditions for any certificate [1]. Condition 12 bars construction until FERC staff receives final comments from the U.S. Fish and Wildlife Service, completes Endangered Species Act consultation and the applicant gets written clearance from the Office of Energy Projects [1]. Condition 13 requires noise surveys within 60 days of service at all four stations and added controls within a year if any station exceeds 55 dBA at a nearby noise-sensitive area [1].

Why did staff prepare an EA instead of an EIS?

Commenters asked for a full environmental impact statement [1]. Staff answered that the project involves “a new compressor station adjacent to the existing Mountain Valley Mainline on previously disturbed land” plus modifications at existing stations, and cited 18 CFR 380.6(b), which has the Commission prepare an assessment first when an action may not be significant [1]. The scoping notice had left the choice open between the two documents [4].

Where it sits in the process

Mountain Valley filed its application on October 23, 2025 [3]. FERC issued a notice of application on November 5, which opened a 21-day intervention and comment window, and a scoping notice on November 19 with comments due December 19 [1, 4]. In January, FERC’s schedule notice set August 7, 2026, for the assessment and November 5, 2026, as the deadline for other federal authorizations, and said the assessment would get a 30-day comment period [3]. Staff met the August 7 date [1].

Three filings followed in the week after issuance:

  • On August 10, staff asked the Fish and Wildlife Service’s Virginia and West Virginia field offices to concur that the project “may affect, but is not likely to adversely affect” the Indiana bat and northern long-eared bat, and gave no-jeopardy determinations for the tricolored bat and monarch butterfly, both proposed for listing [5].
  • On August 12, the Division of Pipeline Certificates sent a data request asking Mountain Valley, within five days, to update flow diagrams for each station and file the hydraulic models behind them [6].
  • On August 14, Del. Sam Rasoul asked FERC to extend the comment deadline to October 8 and hold in-person meetings in all four counties [7].

The assessment is “not a decision document,” the notice says [2]. The Commission decides whether to grant a certificate under the Certificate Policy Statement, weighing need and economic issues along with environmental effects [1, 2]. Only intervenors may seek rehearing or judicial review [2].

Mountain Valley’s own schedule has vegetation clearing at Swann starting in December 2026, construction from January 2027, and a full in-service target of June 2028, subject to permits [1].

What the record does not show

  • A Virginia air permit for Swann. The assessment says an application went to the Virginia Department of Environmental Quality but “a permit has not yet been issued” [1]. West Virginia had already issued permit modifications for the three existing stations [1]. WVTF Radio IQ reported July 3 that DEQ suspended the Swann application because a Montgomery County letter to FERC conflicted with a county form attesting the site was suitable, and that the company would have to restart the process to continue [9]. The FERC record does not say when a new application might be filed.
  • Completed species consultation. Staff’s concurrence request went out three days after the assessment [5]. Until the Fish and Wildlife Service replies, condition 12 holds construction [1].
  • The hydraulic basis. The data request asks for the models supporting the flow diagrams and an explanation of “any discrepancies” between them [6]. Part of Mountain Valley’s response was filed as non-public.
  • A ruling on extra comment time. Staff wrote in the assessment that more scoping sessions and longer comment periods “were not necessary,” but that was before Rasoul’s request, and no order on it appears in the docket [1, 7].
  • Need. The assessment leaves need for the Commission’s order and does not name the shippers on the precedent agreements [1].
  • An internal inconsistency. The land table gives the Swann site 25.1 acres; the alternatives discussion refers to 24.1 acres for the same station [1].

Positions on the record

The assessment counts about 154 comments from the application and scoping stages [1]. Commenters included Montgomery and Craig counties, seven state elected officials, Appalachian Voices, Sierra Club, the Chesapeake Climate Action Network, Protect Our Water, Heritage, Rights (POWHR), four chambers of commerce and the natural gas coalitions of Virginia and the Carolinas [1].

Segmentation. Sierra Club and POWHR argued that the mainline, the Southgate amendment and Boost are “interrelated parts of a larger gas transportation project,” as the assessment summarizes them [1]. Staff disagreed, noting that the nearest Boost facility is more than 65 pipeline miles from the planned Southgate interconnection, that the three projects had separate open seasons and precedent agreements, and that the mainline “is operating at full use” [1].

Alternatives. Preserve Giles and others asked for electric-motor compression [1]. Staff found it would require 2.5 to 6.9 miles of new transmission line per station and estimated it would produce more emissions than gas-fired units at every station, apart from a 0.03 percent PM2.5 reduction at Swann [1]. A pipeline loop that would eliminate Swann would need about 90 miles of 42-inch pipe and 1,364 acres, crossing the Appalachian Trail and the George Washington and Jefferson National Forests [1]. Of three alternative Swann sites, one had 8 noise-sensitive areas within half a mile against 136 at the proposed site, but it would need 20.3 acres of tree clearing and a 3,455-foot access road; staff found no site with a significant advantage [1].

Mountain Valley. The company states it is working to resolve the issues delaying the DEQ permit and has gone beyond regulatory requirements in community engagement, according to the assessment [1]. A spokesperson, Shawn Day, told WVTF in July the company was working to address DEQ’s request [9].

Montgomery County. County Administrator Angie Hill told WVTF that the county letter and the permit form do not conflict: “we don’t have authority over the siting of that station. That rests with FERC” [9]. The county had raised evacuation concerns because the only route from the site can be blocked by trains [9]. The assessment says Mountain Valley has talked with Norfolk Southern about stopping trains in an emergency [1].

Opponents. The Chesapeake Climate Action Network said on August 10 that more than 6,500 people had signed a petition urging rejection [8]. “FERC is trying to build on a foundation that DEQ has already found to be flawed,” said Zander Pellegrino, the network’s senior field manager [8]. Rasoul’s letter cites a Virginia Tech household survey finding that many residents near the Swann site meet EPA guidelines for an overburdened community [7]. The assessment notes that executive orders on environmental justice were revoked in January 2025 but says the Commission still considers “effects on all potentially affected communities” [1].

Whether FERC extends the September 8 deadline is the next open question in the docket.

Reading-room questions

Questions readers bring to this record, answered from the documents cited below.

When are comments due on the MVP Boost environmental assessment?
FERC must receive them by 5:00 p.m. Eastern on September 8, 2026, filed in Docket No. CP26-14-000 [2]. Filing a comment does not make someone a party; intervention deadlines have passed, and late intervenors must show good cause [2].
Did FERC find that the Mountain Valley Pipeline Boost project would harm the environment significantly?
No. Staff concluded approval 'would not constitute a major federal action significantly affecting the quality of the human environment' and recommended a finding of no significant impact with 13 conditions [1]. The full Commission still has to rule on the certificate [2].
Where would the new Swann compressor station be built and how big is it?
In Montgomery County, Virginia, adjacent to the existing Mountain Valley mainline, with three gas turbines totaling 136,900 horsepower [1, 2]. Its construction footprint is about 25.1 acres, with 136 noise-sensitive areas counted within half a mile of the site [1].
Does the Swann compressor station have its Virginia air permit?
Not as of the assessment, which says an application was submitted to the Virginia Department of Environmental Quality but no permit had been issued [1]. WVTF Radio IQ reported in July that DEQ suspended the application [9].
How much greenhouse gas would MVP Boost emit?
Staff estimates about 0.98 million metric tons of CO2e a year from the new equipment and about 72,683 metric tons during construction [1]. The assessment does not label those emissions significant or insignificant and treats downstream emissions as outside its scope [1].

Note on sourcing

The environmental assessment is a staff document, not a Commission order; it does not decide need, rates or whether a certificate issues. Its statements about Virginia's air permit for the Swann station are as of the assessment's date, and the account of the Virginia Department of Environmental Quality suspending that application, and of what restarting would require, comes from WVTF Radio IQ's reporting rather than from a DEQ document. The Chesapeake Climate Action Network release gives a September 6 comment deadline; the Federal Register notice sets September 8, 2026. The petition figure is the network's own count. Mountain Valley's answers to FERC's August 12 data request are in part filed as non-public critical energy infrastructure information, and this report does not draw on them. Mountain Valley had not filed a response to the extension request as of publication.

Sources

  1. Mountain Valley Pipeline Boost Project Environmental Assessment, Docket No. CP26-14-000 (FERC Accession No. 20260807-3005)Federal Energy Regulatory Commission, Office of Energy Projects, August 7, 2026 · elibrary.ferc.gov
  2. Mountain Valley Pipeline, LLC; Notice of Availability of the Environmental Assessment for the Proposed Mountain Valley Pipeline Boost Project, 91 FR 52048 (FR Doc. 2026-16435)Federal Register (FERC), August 12, 2026 · federalregister.gov
  3. Mountain Valley Pipeline, LLC; Notice of Schedule for the Preparation of an Environmental Assessment for the Mountain Valley Pipeline Boost Project, 91 FR 2341 (FR Doc. 2026-00990)Federal Register (FERC), January 20, 2026 · federalregister.gov
  4. Mountain Valley Pipeline, LLC; Notice of Scoping Period Requesting Comments on Environmental Issues for the Proposed MVP Boost Project, 90 FR 52932 (FR Doc. 2025-20781)Federal Register (FERC), November 24, 2025 · federalregister.gov
  5. Request for Informal Consultation for the Mountain Valley Pipeline Boost Project, letter to U.S. Fish and Wildlife Service Virginia and West Virginia field offices (FERC Accession No. 20260810-3031)Federal Energy Regulatory Commission, Office of Energy Projects, August 10, 2026 · elibrary.ferc.gov
  6. Data Request to Mountain Valley Pipeline, LLC, MVP Boost Project, Docket No. CP26-14-000 (FERC Accession No. 20260812-3050)Federal Energy Regulatory Commission, Division of Pipeline Certificates, August 12, 2026 · elibrary.ferc.gov
  7. Letter of Del. Sam Rasoul requesting a 30-day extension of the EA comment period and public meetings, Docket No. CP26-14-000 (FERC Accession No. 20260814-5139)Virginia House of Delegates (filed with FERC), August 14, 2026 · elibrary.ferc.gov
  8. Thousands Urge Feds to Reject "MVP Boost" While Virginia DEQ Suspends Impact ReviewChesapeake Climate Action Network, August 10, 2026 · chesapeakeclimate.org
  9. DEQ suspends MVP compressor station permitWVTF Radio IQ, July 3, 2026 · wvtf.org

Subject headings

Cross-references

Other register entries filed under the same subject headings.

  1. No. 0031 · Floor order · 2 shared headingsSenate order sets Nov. 9 cloture vote on motion to proceed to H.R. 2347, the vehicle for a permitting package
  2. No. 0030 · Report · 2 shared headingsFERC opens scoping on Longboard LNG import terminal off Oʻahu, Docket No. PF26-10-000
  3. No. 0026 · Record of decision · 2 shared headingsFERC staff issues final EIS for Sabine Pass Stage 5 LNG expansion, Docket No. CP24-75-001