Enbridge Begins Work to Assess Line 5 Replacement


Enbridge Inc., operator of the controversial Line 5 under Michigan’s Straits of Mackinac, is in the early stages of studying potential alternatives to the aging underwater liquids pipeline.

The Petoskey News reported Monday (March 12) that crews had begun subsurface sampling around pumping stations near the Straits, the first steps in an agreement reached late last year in which Enbridge will explore three possibilities for “eventually” replacing Line 5.

Line 5, the only pipeline to run under the Great Lakes, has come under fire in recent months after Enbridge admitted that parts of the 65-year-old line’s protective coating have come off. While the company says there is no danger, and the pipeline has never experienced a leak, residents and environmentalists worry that if a rupture occurred, it could adversely affect the ecosystem and the economy of the Great Lakes region.

State Agreement

Last November, after a series of revelations about the condition of the pipeline coating, Michigan Gov. Rick Snyder entered into the agreement with Enbridge, requiring the company to evaluate the potential for its replacement, and to take other steps to ensure the line’s security.

Enbridge will study the possibility of replacing the line with a new pipeline in a tunnel under the Straits, or a pipeline installed via horizontal directional drilling, or a line in a trench with a secondary containment structure around it.

Secondary aspects of the agreement include a requirement to shut the pipeline down when conditions cause waves of greater than 8 feet, and the replacement, already underway, of a shorter stretch of Line 5 that runs under the St. Clair River. That length of pipeline will be installed via horizontal directional drilling.

The agreement does not actually require Line 5’s replacement or put a timeline on the job, but reflects the pressure the state is putting on Enbridge to plan for that outcome.

Some, including members of Michigan’s Pipeline Advisory Board, called in December for an immediate shutdown of Line 5 under the Straits, but Snyder declined to do so, arguing that an unexpected shutdown would have negative consequences for Michigan homeowners who rely on propane from the pipeline to heat their homes.

Last summer, Line 5 passed a hydrotest that was required as part of Enbridge’s consent agreement with the federal government after a 2010 spill on the company’s Line 6B.

Line 3 Debate

Elsewhere, in Minnesota, Enbridge is facing fallout related to another of its pipelines: Landowners along its Line 3 pipeline, which the company hopes to replace as part of the biggest project in its corporate history, want the old Line 3 removed when it is decommissioned.

Enbridge says while exposed portions of the pipe will be removed, its proximity to other infrastructure will make it difficult to remove completely. The company says the replacement of the old 34-inch line with a 36-inch line nearby is necessary because a failing tapecoat may be speeding corrosion on the old line.


Tagged categories: Infrastructure; NA; North America; Oil and Gas; Pipelines; Program/Project Management; Protective Coatings

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