Maintenance on the Rockies Express Pipeline (REX) will shut down receipts and deliveries for two days next week at four locations in the Clarington, OH, area, affecting up to 600 MMcf/d, according to natural gas analytics firm Genscape.

REX backer Tallgrass Energy posted notice to its electronic bulletin board last month that receipts and deliveries will be unavailable at the Dominion-Clarington, TETCO-Clarington, East Ohio Gas-Clarington and Ohio River System-Bearwallow locations from gas day March 21 through gas day March 22.

The maintenance could impact up to 600 MMcf/d flowing through those points, according to Genscape.

East-to-west on REX’s Zone 3 has been flowing at or near max capacity, according to NGI‘s daily REX Zone 3 Tracker.

“But the individual points that feed into that are all running a little bit below what they have flowed at their max,” Genscape analyst Dan Spangler told NGI. “So if these points shut down it seems likely that some of the other points flowing into REX could make up for that capacity.”

This assumes total line pressure on REX isn’t reduced as a result of the Clarington maintenance, he added.

During maintenance events affecting REX Zone 3 last year, receipts increased at nearby points on Dominion Transmission Inc. (DTI) and Texas Eastern Transmission Co. (TETCO) lines, Spangler said, pointing to other possible avenues for any displaced volumes.

After completing its 800 MMcf/d Zone 3 Capacity Enhancement project in January, REX’s total east-to-west designed capacity stands at 2.6 Bcf/d, with Tallgrass recently announcing another 150 MMcf/d. The increased capacity had an almost immediate impact on prices in the region, an analysis of NGI’s Shale Daily indexes has shown.

“The 600 MMcf/d will only be for a couple of days, and it will be happening later in March, when demand tends to be down a bit,” NGI’s Director of Strategy & Research Patrick Rau said. “Gas flowing west on REX heads to the Midwest, and quite a few of the LDCs in that region will likely be pulling on storage the rest of March, especially if they are required to draw down their storage levels before the end of the month.”

Added Rau, “It’s been only since early January that the extra 800 MMcf/d has been flowing through REX from its east-to-west capacity enhancement. That gas ramped up pretty quickly in January, so it was flowing somewhere else before the increase went into service. My guess is a good part of that can be re-routed through TETCO and DTI, but perhaps producers will choke back on their wells for a couple of days.”

The 1,698-mile REX runs from East Ohio to the Rockies and has become a key takeaway route for Marcellus and Utica shale production since reversing a few years ago to offer east-to-west flows through its Zone 3.

Tallgrass Energy, through its affiliates, owns a 75% interest in REX, with Phillips 66 owning the remaining 25%.