The Federal Energy Regulatory Commission (FERC) issued an environmental assessment Friday on the Southgate pipeline, which would receive 550 MMcf/d from the tailgate of Mountain Valley Pipeline (MVP). This assessment does not represent approval by the FERC but will be used to guide the approval decision. The environmental assessment concluded that Southgate would not “constitute a major federal action significantly affecting the quality of the human environment.” However, it also says that the alternative of approving only Transco’s Southeast Supply Enhancement (SSE) would reduce environmental effects, so the commission will have to determine whether market rationales justify the approval of both projects. Transco claimed in filings earlier this year that the 1.6-Bcf/d SSE would be sufficient to supply all the shippers on Southgate. MVP and several of its anchor shippers claim that supply diversity, higher minimum pressure, and alleviated constraints during extreme winter weather justify the approval of Southgate.
Currently Mountain Valley Pipeline runs full in the winter (see purple line in graph below) but is less utilized in the spring and summer, as more gas south of Station 165 comes from legacy Transco pipe originating in Northeast Pennsylvania. Southgate and SSE are both designed to alleviate constraints south of Station 165, so MVP can run closer to capacity year-round.
