Michigan commission approves Line 5 siting permit

The Michigan Public Service Commission (MPSC) approved a Line 5 siting application filed by Enbridge Energy LP for a proposed replacement segment of pipelines now located on the lakebed of the Straits of Mackinac.

Enbridge plans to replace the pipelines with a single pipeline in a tunnel deep below the lakebed, subject to the company obtaining additional government approvals and permits and with conditions related to the tunnel’s safety and construction.

The commission’s order determined there is a public need for the replacement section of Line 5 and the light crude oil and natural gas liquids that it carries. Without the pipeline’s operation, the commission found, suppliers would need to use higher risk and costlier alternative fuel supply sources and transportation for Michigan customers, including those who use propane for home heating.

According to the MPSC, there is a public need to protect the ecological, natural and cultural resources of the Great Lakes, which would benefit from Enbridge’s replacement of the existing dual pipelines, now exposed to the elements and risks, including ship anchor strikes on the Straits’ lakebed.

In fact, the commission adds, the replacement segment would be a significant improvement over the existing dual pipeline configuration, virtually eliminating the risk of anchor strikes, in addition to the replacement segment being housed in a tunnel that can serve as a secondary containment vessel if a leak developed.

Other modes of transporting Line 5’s products, such as by truck, rail, oil tanker or barges, likely would increase environmental impairment and increase the risk of spills that could significantly harm the Great Lakes and its environment, the commission found, and there are no feasible and prudent alternatives to the replacement project aligning with the Michigan Environmental Protection Act.

The commission also found that the route, location and design of the project is reasonable and should be approved, subject to conditions.

Enbridge initially filed its application in April 2020 seeking siting approval under Act 16 of 1929 to replace and relocate the Line 5 section through the Straits of Mackinac into a new tunnel beneath the lakebed. The commission in July 2022 reopened the record in this case, finding the record was deficient on crucial matters of engineering and safety.

First built in 1953, Line 5 is a 645-mile interstate pipeline that originates in Superior, Wisconsin, spans Michigan’s Upper Peninsula, crosses the Straits and then spans the Lower Peninsula before terminating near Sarnia, Ontario, Canada. Line 5 transports light crude oil and natural gas liquids, including propane used for home heating in Michigan. Its average annual capacity is 540,000 barrels per day.

With the MPSC order, Enbridge will be able to proceed with the construction of the replacement pipeline so long as the project receives approval by regulatory agencies, including the Mackinac Straits Corridor Authority and U.S. Army Corps of Engineers. Upon construction of the tunnel, Enbridge will deactivate the existing dual pipelines once the replacement segment is placed into service.

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