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Line 5

On April 17, 2020, Enbridge Energy, Limited Partnership (Enbridge) filed an application with the Michigan Public Service Commission (MPSC or Commission) pursuant to Public Act 16 of 1929, MCL 483.1 et seq, also referred to as Act 16, requesting authority to replace and relocate the segment of Line 5 crossing the Straits of Mackinac into a tunnel beneath the Straits of Mackinac.

On December 1, 2023, the Commission issued an order approving Enbridge’s application subject to a number of conditions. Additional information regarding the Commission’s order and approval can be found in the MPSC’s Line 5 Issue Brief.

What does Enbridge's Act 16 application seek approval for?

The application seeks approval for Enbridge's project known as the Straits Line 5 Replacement Segment Project, which will replace the current crossing - consisting of two, 20-inch diameter pipes referred to as the Dual Pipelines - with a single, 30-inch diameter pipe (the replacement pipe segment) located within a concrete-lined tunnel below the lakebed of the Straits. This application does not request approval of the tunnel itself, which is the subject of separate applications addressed by other state and federal agencies. The application states that Enbridge has acquired the necessary property rights for installation, operation, and maintenance of the replacement pipe segment.

For an overview of the Act 16 process, click here.

In conjunction with its application seeking authority for Act 16 approval, Enbridge requested that the Commission issue a declaratory ruling pursuant to Section 63 of the Administrative Procedures Act of 1969 (being MCL 24.263), and Rule 448, (being R 792.10448) or other finding, that Enbridge already has obtained the authority it needs from the Commission for the project for the reasons set forth in the application. The Commission found that the Line 5 Project differs significantly than what was approved in the 1953 orders, therefore Enbridge's request for declaratory relief was denied and its Act 16 application will be considered by the MPSC through a formal contested case hearing process.

For an overview of the declaratory ruling request, click here.

Why is Enbridge filing an Act 16 application with the Michigan Public Service Commission?

Siting authority for crude oil and petroleum product pipeline siting is granted to the MPSC pursuant to Act 16. Approval under Act 16 allows the applicant to construct the pipeline as specified in the Commission order and subject to any other governmental permits that are required.

U-20763 Case Information

U-20763 Enbridge Act 16 Application Case Docket


MPSC Staff Review of Application: Recording | Presentation

Summary of the Scope of Consultant Review of the Application

Case Schedule (Revised 5/5/21 as directed in the Commission's 4/21/21 Order)

August 24, 2020 Public Hearing Recording

October 23, 2020 ALJ Ruling on Motion in Limine

February 23, 2021 ALJ Ruling on Motion in Limine


November 30, 2023 - Public Notice and Agenda for December 1, 2023 Commission Meeting

September 7, 2022 - Public Notice and Agenda for September 8, 2022 Commission Meeting

July 6, 2022 - Public Notice and Agenda for July 7, 2022 Commission Meeting

April 20, 2021 - Public Notice and Agenda for April 21, 2021 Commission Meeting

December 8, 2020 - Public Notice and Agenda for December 9, 2020 Commission Meeting

August 6, 2020 - Notice of Public Hearing - August 24, 2020

July 1, 2020 - Notice of Hearing - August 12, 2020

June 11, 2020 - Public Notice and Agenda for June 30, 2020 Commission Meeting

April 20, 2020 - Public Notice and Agenda for April 22, 2020 Commission Meeting

Significant Dates

September 14, 2021 - Staff and Intervenor Testimony Due

December 14, 2021 - Rebuttal Testimony Due (All Parties)

February 18, 2022 - Initial Briefs Due

March 11, 2022 - Reply Briefs Due

October 21, 2022 - Enbridge Testimony

February 2, 2023 - Staff and Intervenor Testimony

March 10, 2023 - Rebuttal Testimony

March 29, 2023 - Motions

April 7, 2023 - Response to Motion

May 5, 2023 – Initial Briefs

May 19, 2023 – Reply Briefs

Commission Orders

December 1, 2023 - MPSC Approves siting permit for Enbridge to relocate LINE 5 in Straits of Mackinac, with conditions

September 8, 2022 - Grants the August 5, 2022 joint request for additional briefing on the supplemental record

July 7, 2022 - MPSC reopens record in Line 5 tunnel case to receive more information on engineering, safety from Enbridge

April 21, 2021 - Commission order on appeals to the October 23, 2020, and February 23, 2021 rulings on Enbridge's motion in limine regarding scope of review

December 9, 2020 - Remands Enbridge Energy's motion in limine to the ALJ to allow for new briefing and to set a revised schedule

June 30, 2020 - Denying declaratory relief and request for ex parte approval, sets the matter for hearing

April 22, 2020 - Establishing a period for comment on Enbridge's application

Press Releases

December 1, 2023 - MPSC approves siting permit for Enbridge to relocate Line 5 in Straits of Mackinac, with conditions; finds tunnel best option

September 8, 2022 - Commission addresses outages, utility response, and customer data and privacy in MI Power Grid initiative

July 7, 2022 - MPSC reopens record in Line 5 tunnel case to receive more information on engineering, safety from Enbridge

April 21, 2021 - MPSC order denies bid to revisit public need for existing portions of Line 5, but permits arguments about potential impacts of greenhouse gas emissions related to tunnel application

December 9, 2020 - MPSC orders rehearing, new schedule for Enbridge Line 5 application in light of state's revocation of pipeline easement

August 7, 2020 - MPSC to hold public hearing on Enbridge's request for siting authority to replace, relocate Line 5 in Straits of Mackinac

June 30, 2020 - MPSC denies Enbridge Energy's request for relief on Line 5 pipeline project, sets full hearing process for proposal

April 22, 2020 - MPSC establishes comment period on Enbridge Energy's application for Line 5 tunnel project in Straits of Mackinac

How to Participate

The MPSC provides many opportunities for the public to participate in cases. Customers, business owners, non-profit organizations, and others may share their views by becoming an intervenor, attending and speaking at a Commission meeting or public hearing, providing written comments, or writing a letter to the Commission. For an overview of the Act 16 process and how to participate, click here. You can also monitor the case using the instructions below to receive updates about notices, public hearings, and opportunities to comment.

MPSC Application Overview - In high-profile cases, MPSC Staff will summarize the application, the MPSC's process and standards of review, and explain opportunities for interested persons to participate. This presentation may be recorded and available on the MPSC's website.

Becoming an Intervener - Interested persons wanting to become an official party to the case must file a Petition to Intervene with supporting legal justification through the MPSC's E-dockets system ( by the date provided in the Notice of Hearing and follow the other guidelines described in the notice. The deadline for intervention in Case No. U-20763 was August 5th.

Written comments - Interested persons may submit comments to the Commission regarding your position on this case without being an official party or intervenor. Comments may be submitted at any point during the proceeding and will be filed in the docket for Case No. U-20763 and subject to review by the public and the Commission. Comments can be submitted via email to or by mail to: Michigan Public Service Commission, 7109 W. Saginaw Highway, Lansing, MI 48917. Please be sure to include Case No. U-20763 in your comments.

Commission Meetings - The Commission holds one to two meetings a month, which are held at the MPSC office located at 7109 W. Saginaw Hwy, Lansing, Michigan (or remotely due to COVID-19 precautions; please check website for updates). Any person present at a Commission meeting may address the Commission during the time reserved on the agenda for public comments.

Public Hearings - The MPSC may schedule additional public hearings dedicated to receiving public comment. These hearings allow interested people to share their comments on a pending case before the Commission and are typically held near the project's location or in areas most impacted. For Case No. U-20763, the Commission has scheduled the following public hearing:

August 24, 2020 (Teleconference Only) - 4:00 PM - 7:00 PM EST | Event Details

Case Monitoring - All non-confidential documents filed in this case are available to the public. You can access case information through the docket for Case No. U-20763. If you'd like to receive notifications when new filings are made, click on the orange "Notify Me of New Approved Filings" box within the docket. Updates on significant developments such as the scheduling of public hearings and the issuance of Commission notices or orders will also be provided through the Line 5 email distribution list. Sign up below.

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