South System Expansion 4 Pipeline Project

Docket No. CP25-517-000 and CP25-514-000

Introduction

On January 30, 2026, Federal Energy Regulatory Commission (FERC or the Commission) issued a Notice of Availability requesting public comments on the draft Environmental Impact Statement (EIS) for the Mississippi Crossing Project proposed by Tennessee Gas Pipeline Company, LLC and South System Expansion 4 Project proposed by Southern Natural Gas Company, LLC (Docket Nos. CP25-514-000 and CP25-517-000). Any person wishing to comment on the draft EIS may do so.  

On December 31, 2025, the FERC issued a Notice of Schedule for the Mississippi Crossing and South System Expansion 4 Projects. These projects are covered under Title 41 of the Fixing America’s Surface Transportation Act (FAST-41). Under FAST-41 agencies are to publish completion dates for all federal environmental reviews and authorizations. This notice identifies the Commission's anticipated schedule for issuance of the final orders for the projects, which is based on the anticipated issuance date for the final environmental impact statement (EIS). 

The Commission’s anticipated issuance of the Final EIS is June 26, 2026. 

The Commission’s anticipated issuance of the Final Order is no later than July 31, 2026. 

If a schedule change becomes necessary, additional notice will be provided so that interested parties and the relevant agencies are kept informed of the projects' progress. 

More information can be found in FERC Docket No. CP25-514-000 and CP25-517-000 in FERC’s eLibrary. Please note that the project has not been approved at this time.   

South System Expansion 4 Project – General Overview Map

Project Route and Facilities 

The planned pipeline project will consist of (14) fourteen new natural gas pipeline loops (noncontiguous) that run parallel to SNG’s existing pipeline, South Main Line, totaling approximately 279 miles primarily along existing pipeline in Mississippi, Alabama, and Georgia. The Project also includes expansions to (13) thirteen existing compressor stations and (5) five new meter or regulator stations and modifications to (11) eleven existing meter stations. The planned project would create up to approximately 1.3 million dekatherms per day of capacity on Southern Natural Gas Company, L.L.C.’s pipeline system.

On June 30, 2025, Southern Natural Gas Company and Elba Express Company submitted several maps on the Project to the docket. To view and download these maps, please visit FERC's eLibrary and search Docket No. CP25-517-000. 

Public Participation Opportunities

Schedule for Environmental Review

January 2026 A draft of the Environmental Impact Statement was issued. 
June 2026 The Issuance of Notice of Availability of the final EIS is scheduled. 
September 2026

The Federal Authorization Decision Deadline is scheduled.

There are three methods you can use to submit your comments to FERC.

1. eComment

You can file your comments electronically using the eComment feature in FERC Online. Using eComment is an easy method for submitting brief, text-only comments.

2. eFiling

You can file your comments electronically by using the eFiling feature in FERC Online. With eFiling, you can provide comments in a variety of formats by attaching them as a file with your submission. New eFiling users must first create an account by clicking on “eRegister.” You will be asked to select the type of filing you are making. A comment on a particular project is considered a “Comment on a Filing.”

3. File a paper copy

You can file a paper copy of your comments by mailing them to FERC. Be sure to reference the Project Docket No. CP25-517-000 for South System Expansion 4 Project and CP25-514-000 for Mississippi Crossing Project on your letter. Submissions sent via the U.S. Postal Service must be addressed to:

Debbie-Anne A. Reese, Secretary
Federal Energy Regulatory Commission
888 First Street NE, Room 1A
Washington, DC 20426

Submissions sent via any other carrier must be addressed to:

Debbie-Anne A. Reese, Secretary
Federal Energy Regulatory Commission
12225 Wilkins Avenue
Rockville, Maryland 20852

Public Participation Opportunities - Archived 

During the Pre-filing Process, members of the public had several opportunities to express their views, concerns, and issues with the project:

  • Open Houses hosted by Southern Natural Gas were held between January 27 and March 5, 2025.
  • On March 3, 2025, FERC issued a Notice of Scoping for the South System Expansion and Mississippi Crossing Projects.
  • Scoping comments were due NLT than 5:00 p.m. ET on April 7, 2025.

More Information and Staying Updated 

You may learn more about the Project through FERC's eLibrary. When searching for South System Expansion 4 Project, please enter Docket No. CP25-517-000 in the “Enter Docket Number” text box. When searching for the Mississippi Crossing Project, please enter Docket No. CP25-514-000 in the “Enter Docket Number” text box. FERC’s Office of Public Participation provides an educational video and demonstration on using eLibrary: WorkshOPP and Demonstration: FERC’s eLibrary.  

Stay Informed

Follow OPP on its social media channels:  

OPP regularly sends announcements about upcoming participation opportunities and meetings with interested stakeholders and organizations via its social media channels.  

You may also sign up for FERC’s eSubscription service. eSubscription notifies you via email about submittals and issuances on the project. Please visit www.ferc.gov/esubscription.

You are also encouraged to contact OPP staff to learn more about the Project and participation at FERC by email at [email protected] or phone at 202-502-6595. All media inquiries should be directed to [email protected].

Resources

Guides on Public Participation 

Educational Videos 

Tips on Public Participation 

Informational Handouts 

Background

Office of Public Participation's Outreach Corner

The Office of Public Participation (OPP) is authorized to support public participation in FERC proceedings pursuant to Section 319 of the Federal Power Act. OPP coordinates with and provides assistance to members of the public as to participation in, and understanding of, FERC proceedings. OPP provides outreach to community groups, community members, landowners and other interested parties potentially impacted by infrastructure projects.

OPP’s outreach conducted for the Mississippi Crossing Project in Docket Nos. CP25-514-000, CP25-514-001, PF25-2; and South System Expansion 4 Pipeline Project in Docket Nos. CP25-517-000, CP25-517-001, PF25-1, included:  

  • On January 17, 2025, affected landowners and concerned citizens were notified via the U.S. Postal Service that FERC is seeking public comments on Mississippi Crossing and the South System Expansion 4 Pipeline Projects located in Mississippi, Alabama, and George. FERC educational brochures and letters were mailed to inform landowners and citizens of the project comment deadline.  

  • Coordinated social media campaigns throughout the pre-filing phase and the application phase to notify interested constituents of the comment period, in-person scoping session schedule, and associated deadlines on social media outlets like Facebook, Instagram, and X.  

  • Created a dedicated project website to inform the public of participation opportunities. 

  • Supported FERC’s Office of Energy Projects during the Pre-Filing phase of the project by attending in-person Open House Events January 27 and March 5, 2025, and Scoping sessions held March 24, 2025 – April 3, 2025.   

  • Met with local community leaders who traveled to Washington, D.C. to meet with OPP staff to discuss the project.  

  • Staff met with community members in cities along the pipeline route prior to and during Open House Events January 27 and March 5, 2025, and Scoping sessions held March 24, 2025 – April 3, 2025, to discuss environmental concerns related to the project and how to participate.  

  • Informed the public on the projects transition from the pre-filing phase to the application phase. The projects were assigned FERC Docket Nos. CP25-514-000 for Mississippi Crossing Project and CP25-517-000 South System Expansion 4 Project. Encouraged the public to eSubscribe to the new dockets to stay informed.  

  • Staff sent out a letter through the USPS mail notifying landowners that the Applicant filed a formal certificate application marking the transition from the pre-filing phase in Docket No. PF25-1-000 to the formal application phase in Docket Nos. CP25-514-000 and CP25-514-001.  

  • Staff sent a letter through the USPS mailing informing the public of the Notice of Schedule for the Final Order for the Mississippi Crossing Project and the South System Expansion 4 and the Draft Environmental Impact Statement. 

  • Staff sent an email to the public notifying them of the Notice of Schedule for the Final Order for the Mississippi Crossing Project and the South System Expansion 4 and the Draft Environmental Impact Statement. 

  • Staff sent a letter informing landowners that the Draft Environmental Impact Statement (Draft EIS) was issued and included a schedule of the 11 public comment sessions FERC staff will conduct in the project areas to receive comments on the Draft EIS.  

  • OPP staff attended the Draft EIS comment sessions from February 23, 2026 – March 11, 2026, in Mississippi, Alabama, and Georgia.   

How to Contact

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South System Expansion 4 Contact Us | Energy Infrastructure/Solutions | Kinder Morgan

 

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This page was last updated on May 28, 2026