FERC staff expects to issue an environmental assessment (EA) next month for Columbia Gas Transmission LLC’s (TCO) proposed Buckeye XPress Project in Ohio and West Virginia, which would add another 275 MMcf/d of natural gas capacity to the interstate pipeline system.

The EA is scheduled to be released April 8, with a 90-day federal authorization decision deadline set for July 7, according to a recent filing by the Federal Energy Regulatory Commission.

TransCanada Corp. affiliate TCO began gauging interest in Buckeye XPress two years ago, though it envisioned a larger project at that time. TCO had requested FERC approval to construct and operate the project in April.

Buckeye XPress would include replacing 60.8 miles of aging 20- and 24-inch diameter pipeline with 66.2 miles of 36-inch pipeline in southern Ohio’s Vinton, Jackson, Gallia and Lawrence counties, as well as in western West Virginia’s Wayne County. The project, primarily designed to increase safety and reliability, would replace portions of TCO’s R-system, which was constructed in the 1940s.

The R-system, which supports more than 1 Bcf/d of primary firm transportation, is critical to TCO’s storage operations, according to the application. It provides the main path for gas to move into Ohio for summer storage injections and allows a way for gas to move southward from the Ohio storage fields in the winter.

Buckeye XPress is expected to cost $709 million. In addition to replacing the old pipe, the project would add four mainline valves, four tie-in assemblies, installation of a regulation run at the existing Ceredo compressor station, and two sets of bidirectional launchers and receivers. The additions would help increase transportation capacity to its Leach, KY, interconnection with the Columbia Gulf Transmission system and the TCO pool market in the West Virginia region.

TCO previously set a target in-service date for Nov. 1, 2020.