TUESDAY, JULY 24, 2018
A new risk analysis performed by Michigan Technological University and released in draft form last week indicates that a worst-case release on Enbridge Energy’s Line 5 pipeline under the Straits of Mackinac would sully more than 400 miles of shoreline and come at a total cost of $1.87 billion.
The study, the last bit of evidence to be considered by Gov. Rick Snyder as the state approaches an agreement with Enbridge on the future of the pipeline, was written by representatives of FTU, Michigan State University, Grand Valley State University, Oakland University and the University of Michigan, as well as Loyola University Chicago, North Dakota State University and the National Oceanic and Atmospheric Administration. Its aim is to estimate the risk the pipeline poses to the Great Lakes region.
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| H.G. Judd, CC BY-SA 3.0, via Wikimedia Commons |
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A release from Line 5 into the Straits of Mackinac would have the potential, in a worst-case scenario, to spoil more than 400 miles of coastline in Michigan, Ontario and Wisconsin. |
Line 5 conveys crude oil and natural gas liquids under the Straits (which separates Michigan's Upper and Lower peninsulas, and connects Lake Michigan and Lake Huron); the 65-year-old twin pipeline has been subject to increasing controversy in recent years as evidence of coating delamination and unsupported lengths of pipeline has raised concerns about a release in the Great Lakes. Line 5 has never leaked, and last summer passed a high-pressure hydrotest; Enbridge has said that the pipeline poses no risk to the region, but neighbors, legislators and environmentalists have noted that any spill from the line could cause major damage to the environment in the tourism-heavy region.
Michigan Tech was commissioned earlier this year by the Pipeline Safety Advisory Board to conduct the assessment, which modeled more than 4,300 possible spill scenarios to determine what the maximum possible damage would be from a release. The engineers conducting the study looked at spill location, size, type and how quickly the release would likely be detected to determine the worst possible case.
The worst case, the study notes, would involve a rupture of both of the twin lines, caused either by damage from a third party (such as the anchor strike that hit the lines earlier this year) or by incorrect operation—a "guillotine rupture" caused by overpressuring or hammer shock.
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| Enbridge |
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Line 5 conveys crude oil and natural gas liquids under the Straits (which separates Michigan's Upper and Lower peninsulas, and connects Lake Michigan and Lake Huron).   |
A worst-case release would spread oil along 437 miles of coastline on both Huron and Michigan, spoiling shores as far east as Ontario's Bruce Peninsula or as far west as Sheboygan, Wisconsin, depending on the weather and the lake conditions. Up to 47 species could be affected by such a spill.
The draft study is subject to public comment through September before its final version is published. Snyder is expected to come to a final agreement with Enbridge on the line's future later this fall.
Aside from keeping the pipeline as it is, options Enbridge has said are feasible include a concrete tunnel—which would leave "no feasible scenario" that would result in a release into the Straits—or the new construction of a line with a pipe-in-pipe secondary containment system, which would reduce risk to a "miniscule" level.
Tagged categories: Government; Infrastructure; Oil and Gas; Pipelines; Program/Project Management
