Line 3 Replacement Project

Return to project

Project Scope

  • The Line 3 Replacement (L3R) Program, a multibillion-dollar private investment, consists of 1,031 miles of 36-inch diameter pipeline beginning in Hardisty, Alberta and ending in Superior, Wisconsin; it is one of North America's largest infrastructure programs, supporting North American energy independence. 
  • The U.S. portion of the Program that Enbridge is proposing is known as the L3R Project; the Project consists of replacing existing 34-inch pipe with new 36-inch pipe across 13 miles in North Dakota, 337 miles in Minnesota and 14 miles in Wisconsin. 
  • Overall cost of the Project is estimated at US$2.9 billion in the United States ($2.6 billion in Minnesota).
  • The Project will also include construction of four new pump stations, upgrades to four existing pump stations, and approximately 27 strategically placed valves.
  • In Minnesota, the replacement pipeline will follow the existing Line 3 route from the North Dakota/Minnesota border east to Enbridge's Clearbrook Terminal in Clearwater County, Minnesota. From Clearbrook, the replacement will follow four existing pipelines south from Clearbrook to Hubbard County, then turn east following portions of existing electrical transmission lines, before rejoining the Enbridge Mainline corridor near Chub Lake and continuing in a southeasterly direction to the Minnesota-Wisconsin state border in Carlton County, Minnesota.
  • The Project’s Certificate of Need and Route Permit applications were filed with the Minnesota Public Utilities Commission (MPUC) on April 24, 2015, and accepted as complete on July 1, 2015.
  • The MPUC approved the Line 3 Replacement Project on June 28, 2018, granting a Certificate of Need and approving Enbridge’s preferred route with minor modifications and certain conditions.
  • After the replacement pipeline is built, the existing pipeline will be deactivated in accordance with federal regulations.


Enbridge is responsible for its pipelines, whether they are active or not. Enbridge will continue to monitor the deactivated pipeline and maintain the right-of-way. Once the Line 3 Replacement pipeline becomes operational, the existing Line 3 will be permanently deactivated in place.

Deactivation facts

  • Independent engineering research and analysis, as well as historical knowledge of out-of-service pipelines, have determined that deactivated pipelines with adequate cover will have a very long remaining life as load-bearing structures, even after many decades of deactivation. Enbridge will continue monitoring the right-of-way and mitigate concerns related to our pipeline should a need develop that impacts public safety, the environment or land use.
  • Environmental regulatory requirements prohibit altering current hydrology. Therefore, the Line 3 deactivation process will protect water resources to ensure that the deactivated pipeline will not drain any fields, lakes, rivers, streams or other wetland areas.
  • Enbridge has a vested interest in ensuring that any deactivated pipeline does not compromise land use or the integrity of the other pipelines that share the right-of-way.
  • Enbridge will continue to operate the existing pipeline safely while the new pipeline is installed, because refineries in the Midwest served by the pipeline rely on continuous deliveries of crude oil to provide the gasoline, heating oil, and other products that we use every day.

The deactivation process

  1. Remove the oil from the pipeline: The pipeline is purged of product using an inert gas.
  2. Clean the pipeline: A combination of Pipeline Cleaning Tools (pigs) and cleaning solutions are used to wipe and clean the pipeline.
  3. Disconnect the pipeline: The pipeline is physically disconnected and sealed off from the active operational facilities.
  4. Segmenting the pipeline: Further isolation is employed to protect water resources with the use of the permanent closure of pipeline valves or other means, including cutting and plating.
  5. Monitor the pipeline: Cathodic protection will continue to be applied as needed to protect adjacent pipelines and third party utilities.
  6. Monitor the right-of-way: The pipeline will continue to be monitored with regular pipeline patrols, pipeline signs indicating location, depth of cover surveys and inclusion in “Call Before You Dig” programs.