Pipeline Profiles: Enbridge Mainline

Pipeline system and key points

Updated December 2017

The Enbridge Mainline system is Canada’s largest transporter of crude oil, moving Western Canadian crude oil production to markets in eastern Canada and the U.S. Midwest. The Mainline also transports refined petroleum products to Saskatchewan and Manitoba and natural gas liquids to Sarnia, Ontario. The first leg of the Mainline from Edmonton, Alberta to Superior, Wisconsin was built in 1950. In 1953 it was extended to Sarnia, Ontario. The Mainline has been expanded and upgraded during the last thirty years to its current configuration and capacity.

The Mainline originates in Edmonton, Alberta and extends east across the Prairies. It receives western Canadian and U.S. crude oil from feeder pipelines at Kerrobert and Regina in Saskatchewan and Cromer in Manitoba. The pipeline crosses the Canada-U.S. border near Gretna, Manitoba, where it joins with the Enbridge Lakehead system.

At Clearbrook, Minnesota, the Mainline receives U.S. crude oil from the Enbridge North Dakota pipeline and connects with the Minnesota Pipe Line that delivers crude oil to refineries in Minnesota and Wood River, Illinois.

At Superior, Wisconsin the Mainline branches in two segments. The northern pipeline passes through northern Wisconsin and Michigan before crossing into Ontario at Sarnia. The southern leg contours south of Lake Michigan to Lockport and Chicago in Illinois before turning northeast passing though Indiana and Michigan. It re-enters Canada at Sarnia, Ontario.

Map – Enbridge Pipelines Inc. Mainline

Source: NEB

Text version of this map

This map provides an overview of the Enbridge Mainline Pipeline System.

At Sarnia, the Mainline connects with Line 7 and Line 9, which deliver crude oil to Montreal, Quebec, Nanticoke, Ontario and Warren, Pennsylvania. There is also a lateral pipeline connecting Sarnia to the Mid-Valley pipeline system, which delivers crude oil to refineries in Michigan, Ohio and the U.S. Gulf Coast.

Two laterals (Lines 14 and 79) from Stockbridge, Michigan link the Mainline to refineries in Toledo, Ohio. At Chicago and Flanagan, Illinois, the Mainline links with the Southern Access Extension Pipeline (SAX), Mustang, Spearhead South and Chicap pipelines to deliver crude oil to pipelines and refining hubs at Patoka, Illinois and Cushing, klahoma.

Enbridge Mainline System Configuration (2016)

Figure 1: Enbridge Mainline System Configuration Details

Figure 1: Enbridge Mainline System Configuration Details

Source: Enbridge

Text version of this graphic

This diagram provides an overview of the configuration of the Enbridge Mainline System.

In December 2015, the Line 9B Reversal and Line 9 Capacity Expansion Project became operational, enabling Quebec refiners to access western Canadian crude oil by pipeline.

In 2014 and 2015, Enbridge completed the Canadian portions of the Alberta Clipper (Line 67) Expansion Project, increasing capacity by a total of 55 600 cubic metres per day (m3/d) (350 thousand barrels per day (Mb/d)) to the full design capacity of 127 100 m3/d (800 Mb/d). This, together with flexibility enhancements, has resulted in higher throughputs on the Enbridge Mainline.

In November 2014, an application for the Line 3 Replacement Program was filed with the Board. It sought to restore the capacity of the pipeline to 127 200 m³/d (760 Mb/d) by 2019. On 25 April 2016, the Board concluded that the Enbridge Line 3 Replacement Program would be in the Canadian public interest and issued its recommendation for project approval to the federal Governor in Council (GIC). The GIC approved the project on 29 November 2016.

Official Board documents related to the construction, operation and maintenance of the Enbridge Mainline pipeline can be found here: Enbridge Mainline regulatory documents [Folder 92263].

Throughput and capacityFootnote 1

Updated quarterly

Open data can be freely used and shared by anyone for any purpose. The data for these graphs are available.


Updated December 2017

A toll is the price charged by a pipeline company for transportation and other services. Tolls allow pipeline companies to safely operate and maintain pipelines. Tolls also provide funds for companies to recover capital (the money used to build the pipeline), pay debts, and provide a return to investors. The interactive graph below shows the tolls for key paths on the pipeline since 2006.

Mainline tolls are set according to a negotiated settlement, the Competitive Toll Settlement (CTS), which is in effect from 2011 until 2021. The tolls are fixed, meaning they don’t change a lot from year to year. However, tolls are adjusted annually with the gross domestic product index and other factors. Because tolls are fixed, if throughput decreases Enbridge faces additional financial risks compared to the previous cost of service tolling method. Shippers pay international joint tolls for crude oil shipped from Canada to the U.S., or Canadian tolls for crude oil shipped solely within Canada. These tolls are based on volumes, the various pipeline routes (combinations of receipt and delivery points) and the qualities of the crude oil to be shipped.

Official Board documents related to the traffic, tolls and tariffs for the Enbridge Mainline can be found here: [Folder 155829].

Abandonment funding

Updated May 2018

The Board requires pipeline companies to set aside funds to safely cease operations of a pipeline at the end of its useful life. In 2016, Enbridge Pipelines Inc. estimated it would cost $1 743 million to do this for the Enbridge Mainline. These funds will be collected over 40 years and are being set aside in a trust. Official Board documents related to abandonment funding can be found here, sorted by year and by company: abandonment funding documents [Folder 3300366].

Financial resource requirements

Updated March 2018

The National Energy Board Act requires major oil pipeline companies to set aside $1 billion to pay for the costs of any incident that occurs, such as a spill. See sections 48.11 to 48.17 of the Act for more information. Enbridge Pipelines Inc. demonstrated that is has financial resources in excess of $1 billion dollars. Official Board documents related to the Enbridge’s financial resources can be found here: Enbridge financial resources documents [Folder 2955535].

Pipeline financial information

Updated December 2017

Pipeline companies report important financial information to the Board quarterly or annually. A strong financial position enables pipeline companies to maintain their pipeline systems, attract capital to build new infrastructure, and meet the market’s evolving needs. The data in this table comes from Annual Filing of CTS (Competitive Toll Settlement) Reports [Folder 805818] with the Board.

The Enbridge Mainline operates under a negotiated settlement. Enbridge is not required to report actual return on equity, however it provides this information to its shippers.

Table 1: Enbridge Mainline financial data
Enbridge Mainline financial data 2012 2013 2014 2015 2016
Rate base (millions) $5193 $5683 $6387 $8785 $8824

Corporate financial information

Updated December 2017

The Enbridge Mainline is owned by Enbridge Pipelines Inc., a subsidiary of Enbridge Inc. In 2016, earning from the Canadian portion of the Mainline accounted for approximately 21% of Enbridge Inc.’s profits. Financial ratios continue to be stable and credit ratings are investment grade.

Credit ratings and financial ratios provide an idea of the financial strength of a company, including its ability to attract capital to build new infrastructure and meet financial obligations. The credit ratings below are expert opinions of how likely the debt issuer is to live up to its obligations. The financial ratios provided below were calculated by DBRS.

Table 2: Enbridge Pipelines Inc. financial ratios and credit ratings
Enbridge Pipelines Inc. financial ratios and credit ratings 2012 2013 2014 2015 2016 2017
Revenues (millions) n/a $1242 $1222 $697 $2757 n/a
DEBIT Interest coverage ratio 2.39 2.60 2.37 2.68 3.26 n/a
Cash flow to total debt ratio n/a n/a 12.4% 13.5% 15.3% n/a
DBRS Credit Rating A A A A A A
S&P Credit Rating A- A- A- BBB+ BBB+ BBB+

Note: In 2015 Enbridge completed a restructuring process and transferred certain assets from Enbridge Pipelines Inc. to Enbridge US Holdings Inc. Revenue was reported differently prior to the transfer and was broken out for 2013 and 2014, but is not available for prior years.profits.

Financial regulatory audits

Updated March 2018

The Board audits pipeline companies to confirm compliance with the National Energy Board Act, regulations, Board orders and Board decisions. Financial regulatory audits focus on toll and tariff matters such as detecting cross-subsidies. Enbridge Mainline’s last audit was completed in December 2009. Official Board documents related to Enbridge Mainline’s financial regulatory audits can be found here: [Folder 587320]

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