Regulatory Approvals in Place, but Easement Remains Pending
On January 10, 2024, the Michigan Department of Environment, Great Lakes, and Energy and the Michigan Public Service Commission issued key permits for the tunnel project. These included a wetlands permit and a construction permit specifically for the tunnel itself. Enbridge’s plan involves drilling a concrete tunnel 100 feet beneath the lakebed of the Straits of Mackinac, which connects Lake Michigan and Lake Huron. A new pipeline would be encased within that tunnel, replacing the existing dual pipelines that have been in continuous service since 1953.
The tunnel project is estimated to cost $500 million. It is designed to reduce the risk of a spill in the ecologically sensitive waterway, a concern that has driven years of debate. The existing Line 5 pipeline, of which this segment is a part, stretches 645 miles from Superior, Wisconsin, to Sarnia, Ontario. It is part of Enbridge’s Lakehead System and transports up to 540,000 barrels of synthetic crude, natural gas liquids, and other oil products per day. The pipeline’s crossing beneath the Straits of Mackinac has drawn sustained scrutiny due to the potential environmental impact of a leak in that location.
Despite the permits, the project still requires a final easement from the Michigan Department of Natural Resources. That easement has not yet been granted. Without it, construction cannot proceed regardless of the permits already issued. The unresolved easement represents the next major decision point for state officials.
Environmental and Tribal Lawsuits Complicate Path Forward
Legal hurdles remain substantial. Environmental groups and Native American tribes have filed lawsuits challenging the permits, arguing the project violates state environmental laws and treaty rights. Among the litigants are the Bay Mills Indian Community and the National Wildlife Federation, both of which have active litigation underway. The challenges argue that the regulatory approvals did not adequately account for the potential harm to the Great Lakes ecosystem or the treaty-protected fishing and resource rights of indigenous communities.
These legal proceedings must run their course before any final determination can be made on the project’s viability. The ongoing litigation adds further uncertainty to a timeline that already lacks a clear trajectory. The combination of the missing easement and the unresolved lawsuits means the tunnel project has regulatory approvals under the hood but remains legally contested, with no clear date for when—or if—construction will begin.
The outcome of this multipronged approval process will affect energy transport between the United States and Canada, as Line 5 is a critical link for moving oil and natural gas liquids from the Midwest to eastern Canada. It will also determine the level of protection afforded to a key Great Lakes ecosystem, a waterway that supports fishing, tourism, and drinking water for millions of people. For now, the project remains in legal and regulatory limbo, with state and federal authorities, tribal nations, and environmental groups all awaiting the next developments.
