The ambitious project to house the Line 5 pipeline within a protective tunnel beneath the Straits of Mackinac has faced a significant setback, with officials announcing that completion is now delayed until at least 2031.

During a Friday afternoon meeting, the Mackinac Straits Corridor Authority (MSCA) revealed the revised timeline, which pushes the finish line back by several years from previous estimates. 

The delay underscores the persistent friction between energy infrastructure goals and a complex web of regulatory and judicial oversight.

Stephen Ward, the Line 5 project manager, attributed the shift to a combination of ongoing permitting hurdles and sustained legal challenges. 

The project, overseen by Canadian energy firm Enbridge, aims to replace the existing dual pipelines currently resting on the lakebed with a single pipe secured inside a concrete-lined tunnel deep beneath the lake floor.

“There’s, you know, lots of things can happen between now and then,” Ward told the authority. He emphasized that the 2031 date remains a “rough timeline” rather than a final deadline.

According to Ward, a firm completion date will only be established once the project clears specific regulatory milestones. 

“Part of the process, if we do get to that point, there will be an estimated construction schedule that will be required to be submitted,” he said.

The project’s immediate future rests with federal regulators, with the U.S. Army Corps of Engineers expected to issue a critical ruling on federal permits as early as March 9. 

This decision is viewed as a "make-or-break" moment for the project’s momentum, as it has already been the subject of years of environmental impact studies and public testimony.

Last week, the U.S. Army Corps of Engineers issued a final permit allowing Enbridge to begin construction on a 41-mile segment of Line 5 pipeline, bypassing the Bad River Reservation.  

The Line 5 pipeline remains a flashpoint in Great Lakes politics, with proponents arguing the tunnel is the safest way to transport natural gas liquids and crude oil, while opponents advocate for the total decommissioning of the line to protect the freshwater ecosystem.