THURSDAY, MAY 17, 2018
The early-April incident that severed an electric cable under Michigan’s Straits of Mackinac left Enbridge Energy’s Line 5 pipeline with dents of up to three-quarters of an inch, according to the company, which may add protective sleeves to the affected area of the twin lines.
A tug operated by VanEnkevort Tug and Barge is believed to have dragged its anchor across the Straits in the area of the liquids pipelines and American Transmission Company’s electric lines, causing damage that was discovered April 1. One of the ATC cables was severed, causing a 600-gallon spill of dielectric fluid into the water.
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A tug operated by VanEnkevort Tug and Barge is believed to have dragged its anchor across the Straits in the area of Line 5, causing damage that was discovered April 1. |
Enbridge temporarily shut down Line 5 after the incident, restarting it April 4 but revealing more than a week later that the twin pipelines were dented, presumably by the same strike that damaged the cable. Last week, the company revealed that the lines sustained dents of one-half to three-quarters of an inch. The company says the dents did not affect the 1-inch wall thickness of the 20-inch-diameter pipes.
On Monday (May 14), MLive reported that the company is likely to cover the affected areas with a protective wrap.
Pipeline Controversy
Line 5 has been a lightning rod for criticism in recent years due in part to its status as the only liquids pipeline running under the Great Lakes. Last year, Enbridge revealed that the lines’ protective coating had gaps, but only after a series of statements that critics, including Michigan’s governor, characterized as less-than-forthcoming.
In March 2017, a month after insisting the coal-tar enamel coating was intact, the company admitted there were 18 areas of coating delamination on the pipeline, but said that only the outer layer was affected, and that the company would not take steps to make repairs because the main coating was still intact. The company said at that time that there were no holidays, or areas of bare metal, on the pipeline.
The revelation in August that there were a number of areas of bare metal, some as large as one square foot, came with a promise that the company was working on repairs.
State Agreement
In December, Gov. Rick Snyder inked an agreement with Enbridge in which the company will explore options for the pipeline’s eventual replacement, though it does not place a timeline on the potential project. The twin lines could be replaced with a pipeline in a tunnel, one installed via horizontal direction drilling or one in a trench with a secondary containment structure around it.
After the damage was sustained in the reported anchor strike last month, Enbridge reduced the pipeline’s maximum operating pressure, though the company says the move did not affect its normal pressure, which is considerably lower than the maximum.
Enbridge has held that the pipeline’s integrity has never been compromised. The line has never had a leak in over six decades of service, and last summer, it passed a pressure test ordered as part of the company’s consent agreement, established after the 2010 spill on its Line 6B.
Tagged categories: Infrastructure; Oil and Gas; Pipelines; Quality Control
