Most expansions in pipelines progress sequentially as each review progressively narrows down uncertainty and defines what is ultimately buildable. One of the most critical of the various stages of progressive narrowing of uncertainty is the completion of an environmental assessment or an impact statement at the federal level, and this is where Kinder Morgan’s South System Expansion 4 (SSE4) pipeline project has progressed to.
A critical review stage enters public view
Late in January 2026, Staff members at the Federal Energy Regulatory Commission (FERC), the U.S. federal government’s primary energy regulator, released a Draft Environmental Impact Statement (DEIS) that encompasses both the South System Expansion 4 project and the Mississippi Crossing pipeline project.
This release of the DEIS formally moves SSE4 through the review process required by the National Environmental Policy Act (NEPA) and allows interested parties to make comments prior to the issuance of any permit. A draft Environmental Impact Statement does not constitute an approval.
Rather, the draft EIS is FERC’s initial analysis of potential environmental impacts associated with the construction and operation of the proposed facilities. All interested parties are invited to submit comments; the current comment deadline is set for March 23, 2026.
What does the environmental assessment cover?
The South System Expansion 4 project is being developed by Southern Natural Gas Company and Elba Express Company, two Kinder Morgan subsidiaries. As described in the Draft Environmental Impact Statement, SSE4 would require the construction of several pipeline loops running in parallel to existing pipeline infrastructure across Mississippi, Alabama, and Georgia, along with upgrades to existing compressor stations and metering facilities.
The project is intended to increase the daily transportation capacity of the south main line system by approximately 1.3 billion cubic feet per day. Much of the work would take place on or adjacent to existing pipeline rights-of-way. Therefore, this is an example of a “brown field” approach and will result in significantly less new land being disturbed than would be necessary if entirely new corridors were built.
The Draft Environmental Impact Statement assesses numerous elements of the project, including but not limited to:
- Land use
- Water resources
- Wildlife habitats
- Air quality
- Potential cumulative impacts.
The document also evaluates alternative scenarios and possible mitigation measures that could be implemented if the project is approved.
Why this step matters for project timing
The issuance of the Draft Environmental Impact Statement is one of the last major analytical steps that FERC must complete before issuing its final order on the project. In addition, SSE4 has been designated a FAST-41 covered project, and therefore, all federal agencies are working under a coordinated permitting schedule with published deadlines.
According to FERC’s current permitting schedule, the Final EIS is expected to be completed by the end of June 2026. Assuming the review process remains on track, a certificate order approving the project could be issued by July 31, 2026. While the dates provided represent a likely timeline for the issuance of the Final EIS and certificate orders, they are not guaranteed. However, these dates will provide much-needed clarity regarding the time frame when regulatory uncertainty may begin to dissipate.
A procedural milestone with strategic implications
While the environmental review process may seem like simply a matter of procedure, it frequently determines whether a project can transition from planning to execution. FERC’s decision to proceed with the environmental review of the South System Expansion 4 pipeline represents a pivotal moment in the project’s development. Although no final decision has yet been made, the issuance of the Draft EIS clearly brings the proposal into sharper focus and indicates that SSE4 is rapidly approaching the final stages of federal review.
