Pipelines in Canada

Pipelines are systems of connected pipes used to transport liquids and gases — namely oil and natural gas — across long distances from source to market. More than 840,000 km of pipelines criss-cross the country, part of a larger oil and gas sector that employs between 100,000 and 200,000 Canadians. According to Natural Resources Canada, the sector earns the government an average of $19 billion in royalties, fees and taxes each year. It also contributes nearly 8 per cent of Canada’s gross domestic product.

Yet pipelines have also been controversial in Canada over fears that the fossil fuel use they facilitate could be significantly contributing to climate change. In recent years, Indigenous groups, environmentalists, municipalities, mayors and labour unions have opposed numerous pipeline projects they believe could contaminate local waterways through spills and leaks.

Aerial view of pipeline construction
Gas pipeline construction
String of unassembled natural gas pipeline sections.
Oil terminal with storage tanks and pipeline

Irving oil terminal in St. John's, NL. Photo taken on 19 September 2016.

Enbridge Line 9 pipeline (existing)
TransCanada Energy East pipeline (cancelled)
Edward Burtynsky, Alberta Oil Sands #10, Fort McMurray, Alberta (2007)


The discovery of fossil fuels in Canada began in Enniskillen Township, near Sarnia, Ontario, in the 1850s ( see Petroleum Industries). The construction of pipelines to carry crude oil and natural gas to domestic (and eventually foreign) markets soon followed. For a century after the Sarnia-area oil discovery, the pace of pipeline construction was slow, with just three major routes (from Turner Valley, Alberta to Calgary; coastal Maine to Montreal; and the US Midwest to Ontario) in production.

But in the late 1940s, sufficient reserves of oil and natural gas were developed in Alberta at the Leduc No. 1 oil field to justify a monumental and rapid pipeline expansion to get crude oil to markets in Eastern Canada and the United States. By the end of the 1950s, new pipelines were being built to ship oil from distant wells into Edmonton and, from there, to Vancouver and south to link up with American pipelines. This capacity expanded greatly from the 1970s to 2010s with the construction of additional pipelines linking Canadian oil and natural gas fields with refineries in Alaska, Illinois and Oklahoma.

Leduc oil discovery
Imperial Oil Leduc #1 Well, Leduc oil fields, the day the well blew on 13 February 1947.
Petroleum Basins
Oil refinery
Small oil refinery near Grande Prairie, Alberta. Photo taken on 15 July 2017.
Oil refinery
Oil refinery (heavy oil upgrader) in Regina, Saskatchewan.
Oil refinery
An oil refinery at night near Halifax, Nova Scotia.

Major Pipelines in Canada

Today, more than 840,000 km of pipelines are laid out across Canada, beginning in Alberta and going west to British Columbia, north to the Northwest Territories, south to Texas, and east to Quebec. Gathering pipelines, feeder pipelines and transmission pipelines transport crude oil, natural gas and liquefied natural gas from wells to collection points, across provincial and national borders. Distribution pipelines deliver some natural gas products directly to consumers. According to the Canadian Association of Petroleum Producers, 99.999 percent of all the oil and gas moved by pipeline in Canada arrives at its destination.

Major crude oil pipelines currently operating in Canada include:

Pipeline Route Capacity
Enbridge Mainline Alberta to Wisconsin 2.5 million barrels/day
TC Energy Keystone Alberta to Illinois 591,000 barrels/day
Trans Mountain Pipeline (Government of Canada) Alberta to British Columbia 300,000 barrels/day
Enbridge Line 9 Sarnia, Ontario to Montreal, Quebec 300,000 barrels/day
Spectra Express Alberta to Wyoming 280,000 barrels/day

Major natural gas pipelines currently operating in Canada include:

Pipeline Route Capacity
Nova Gas Transmission Ltd System Alberta 475 million cubic metres/day
TC Energy Mainline Alberta to Quebec 445 million cubic metres/day
Alliance Pipeline British Columbia to Saskatchewan 48 million cubic metres/day
Westcoast Pipeline Northwest Territories to British Columbia 45 million cubic metres/day
Maritimes and Northeast Pipeline New Brunswick to Nova Scotia 15 million cubic metres/day

Many large-scale pipeline projects have been rejected by the federal government or withdrawn in recent years (see Politics and Controversy; Notable Pipelines Proposals). Enbridge’s Northern Gateway pipeline, from Alberta to Kitimat, BC, was rejected by Prime Minister Justin Trudeau in November 2016 over Indigenous opposition and concern about marine spills. TC Energy’s Keystone XL project was conditionally approved by the National Energy Board before former US president Barack Obama killed the project in 2015, a decision that President Donald Trump’s White House subsequently reversed. Another TC Energy project, the Energy East pipeline, was intended to carry upward of 850,000 barrels of oil each day from Alberta to refineries in Quebec and New Brunswick. In October 2017, TC Energy abandoned Energy East and the proposed Eastern Mainline. The Mackenzie Gas Project, which would have transported natural gas from the Mackenzie Delta to northern Alberta, was cancelled by Imperial Oil and its partners in 2017.

How Do Pipelines Work?

A simple pipeline is a long length of connected pipes with pumps, valves and control devices to help convey liquids or gases. A pipeline network consists of gathering systems, trunk lines and distribution systems — parts that are analogous to the roots, trunk and branches of a tree. The gathering system transports a mixture of oil, gas and sometimes water from a production well to collection points, such as processing plants or refineries. Here, any water or contaminants in the pipeline are removed from the fossil fuel.

Gas pipeline valve

The trunk (consisting of the main pipelines) moves oil or gas at high pressures over long distances through large-diameter pipes from a collection point to markets. The energy needed to overcome friction in the pipes themselves is supplied by pump stations (for liquids) and compressor stations (for gas) spaced at intervals. As markets expand, the capacity of the trunk lines can be increased by installing parallel lines (known as “loops”) or adding more pumps or compressors. In the case of oil, trunk lines supply the refineries that, in turn, distribute the fossil fuel to retailers by truck or product pipelines.

Natural gas is withdrawn from the trunk line and delivered to consumers through the distribution system. This part of the network is the longest of the three systems. Typically, the pipes in this system are of small diameter and operate at low pressure.

How Are Pipelines Built?

Pipeline construction
Welders work to build an oil pipeline.
Pipeline construction
Duvernay pipeline
Gas pipeline construction
String of unassembled natural gas pipeline sections.

Most pipelines are constructed of steel, although plastic and aluminum are occasionally used in the construction of natural-gas distribution networks. Steel pipelines are formed by welding sections of pipe together. After the welds are X-rayed to detect any flaws, the pipe is wrapped with a protective coating and buried. All pipelines, regardless of type, are then inspected and pressure tested before being put into service. For plastic lines of a small diameter, the pipe can be unreeled from a large spool pulled by a large tractor, a quicker method for laying pipeline.

The usual depth of burial is about 1.5 m for large pipes and slightly less for small pipelines, although some lines, like the Interprovincial crossing the Strait of Mackinac, are buried at depths exceeding 70 m. Canada is a world leader in winter pipeline construction, having developed unique trenching machines for permafrost and muskeg. Canadian pipeline companies have designed and constructed pipelines in Russia, China and Southeast Asia.

How Are Pipelines Monitored and Maintained?

Pipelines operate every day of the year. Computerized operation allows pressure, flow and energy consumption throughout the line to be continuously monitored. Computers can perform leak detection calculations quickly and initiate remedial actions in case of emergency, such as closing emergency valves, shutting off pumps and alerting repair crews (see also Computer Systems Applications). However, research suggests that operating stations catch only about 15–20 per cent of pipeline leaks. Companies also still frequently use “non-continuous” detection systems, which include dogs and visual inspections such as aerial monitoring from helicopters.

As a further precaution, periodic tests are made to assure a pipeline’s safe operation. Wax and foreign materials can be removed from oil lines by a process known as “pigging.” A “pig” is a bristle-covered cylinder that is pushed through a pipeline by fluid pressure, cleaning the pipe as it goes. The term pigging is derived from a squeal noise made as the bristles rub against the pipe wall. Today, “smart pigs” are equipped with sensors and recorders that monitor the inside of a pipeline for corrosion and weak spots. Pressure testing may be used in conjunction with, or in place of, “smart pig” inspections.

Oil pipeline pig
Smart Pig
Pipeline monitoring by "smart pig." Photo taken on 9 December 2013.

How Are Pipelines Regulated?

Canada’s first Pipelines Act was passed in 1949. This federal legislation created guidelines and safety requirements for how and where pipelines were built. A decade later, the federal government established the National Energy Board (NEB), an independent agency that has the authority to regulate pipelines crossing provincial or international borders and the export of crude oil and natural gas.

In addition, the NEB also considers issues related to pipeline construction, such as petroleum reserve estimates, costs, environmental factors, and engineering and safety practices. Historically, the NEB has also conducted environmental assessments of proposed energy infrastructure projects. And in rare cases, a commission may be appointed to examine a particular project, as happened for the Mackenzie Valley pipeline in the 1970s when environmental claims and Indigenous land claims complicated the review process beyond the board’s mandate.

Politics and Controversy

Pipeline construction has been a political flashpoint. A TransCanada (now TC Energy) pipeline, now known as the Canadian Mainline, was heavily debated in 1956, and intense controversy surrounded the Mackenzie Valley pipeline, a project that was indefinitely deferred in the 1970s, resurrected by Imperial Oil in 2004 and abandoned in 2017.

Trans Mountain pipeline protest

Rally against Kinder Morgan's proposed Trans Mountain Expansion on Burnaby Mountain. Photo taken 17 November 2014.

Northern Gateway pipeline protest
A collection of signs posted by First Nations in Haida Gwaii protesting the building of the Northern Gateway pipeline. Photo taken on 22 February 2013.

The Trans Mountain Expansion Project, originally owned by Kinder Morgan and now owned by the Canadian government, has also been a focus of ongoing political conflict. In early 2018, a trade dispute broke out between British Columbia (a vocal opponent of the pipeline under NDP Premier John Horgan) and Alberta when Horgan’s government proposed a ban on increased shipments of bitumen from Alberta. Months of feuding between the provinces followed.

Did you know?
In May 2018, with Kinder Morgan threatening to abandon the project in light of ongoing opposition in BC, the federal government made the controversial decision to purchase the Trans Mountain pipeline and expansion for $4.5 billion. That August, the Federal Court of Appeal ruled on challenges launched by six First Nations, two environmental groups and the cities of Burnaby and Vancouver. The court found flaws in the government’s approval of the project, and the decision halted the expansion and ordered that parts of the process be redone (see Trans Mountain Expansion Project).

Indigenous consultation and approval of pipeline projects have become key factors in their acceptance by governments, regulators and the public. Before the successful legal challenge to the Trans Mountain Expansion Project, First Nations in British Columbia also used the court system and the government’s duty to consult to oppose the Northern Gateway pipeline. More recently, in the winter of 2018–19, two checkpoints set up by a group of Wet’suwet’en (see Dakelh) activists to block construction of TC Energy’s Coastal GasLink pipeline through their traditional territories made national headlines. Sympathetic groups held demonstrations across the country in support of the Wet’suwet’en pipeline opponents, 14 of whom were arrested by the RCMP in January 2019. Coastal GasLink is also divisive among the Wet’suwet’en, however, with some hereditary leaders and elected band councils supporting the project.

A central concern of many Indigenous communities is the risk that comes with situating oil and gas infrastructure in or near the habitats of wild food sources on which they rely. Health risks are also a concern at points of extraction: beyond contaminated drinking water is the fear that living in close proximity to fossil fuel extraction may increase cancer rates, as was shown in a University of Manitoba-Health Canada study of the Athabasca Chipewyan and Mikisew Cree First Nations in 2014 (see also Dene; Cree). Both of these communities are located close to Alberta’s oil sands.

Map of the oil sands
Extracting and refining bitumen from Alberta's oil sands requires an immense amount of water, much of which ends up as toxic waste in tailings ponds. A planter walks past a pond he is helping to reclaim by planting trees for a major oil company.
Mining the oil sands
Very heavy equipment is required to haul the tarlike bitumen from the earth so that it can be processed and refined to make oil.

Certain pipeline projects have received the support of Indigenous communities. For example, the Inuvialuit Regional Corporation, the Gwich’in Tribal Council and the Sahtu Pipeline Trust partnered on the Mackenzie Gas Project as the Aboriginal Pipeline Group (see also Inuvialuit; Gwich’in; Sahtu Got’ine). The Eagle Spirit pipeline, a proposed alternative to Northern Gateway, is backed by several First Nations seeking to build an Indigenous-owned pipeline.

Environmentalists have begun to insist that oil companies, governments and the NEB consider the upstream greenhouse gas implications of pipelines that facilitate the extraction and combustion of more fossil fuels. At the Paris Climate Change Conference in December 2015, Canada agreed to reduce its carbon emissions to 523 megatonnes per year by 2030, equivalent to a 30 per cent reduction below 2005 levels. While Canada is already unlikely to meet its Paris targets, some have argued that task will be made impossible by increasing pipeline capacity linked to the Alberta oil sands. ( See also Climate Change.)

Global Carbon Dioxide Emissions from Fossil Fuels
The amount of carbon dioxide in the atmosphere has increased rapidly since the Industrial Revolution. \r\n
Greenhouse Effect
The rays of the sun reach Earth (1) and are reflected upwards (2). The balance of heat gained and lost is upset by gasses and particles in the atmosphere (3). These gasses act like the glass in a greenhouse, preventing the heat from escaping (4).

The system for pipeline approval itself has also been criticized, with some claiming Canadians have lost faith in the NEB’s ability to judge energy projects impartially. In the winter of 2016–17, a government-appointed expert panel met with industry, stakeholder and Indigenous groups as part of a massive push to overhaul how the NEB reviews and approves projects in the future.

Notable Pipeline Proposals

In recent years, proposed pipeline projects have generated much discussion in Canada, charting a complex path through political, legal and social channels. Among those proposals that remain active are the Trans Mountain Expansion Project initiated by Kinder Morgan and now owned by the federal government, TC Energy’s Keystone XL and Enbridge’s Line 3 Replacement Project. Enbridge’s Northern Gateway pipeline and the Imperial Oil-led Mackenzie Gas Project, on the other hand, have been halted.

Trans Mountain Expansion Project

Proposed and existing paths of the Kinder Morgan Trans Mountain Pipeline, focusing on Burnaby Mountain, Burnaby and Coquitlam (2014).
(courtesy of Wilderness Committee/map by geoffsen)

The $7.4 billion Trans Mountain Expansion Project was first proposed by Kinder Morgan in 2013. The pipeline would carry diluted bitumen, or “dilbit,” from Edmonton, Alberta to Burnaby, British Columbia. Existing pipeline segments would be reactivated, and approximately 980 km of new pipeline would be built parallel to existing pipelines that had been owned and operated by Kinder Morgan since 1953. The expansion would increase the pipeline route’s overall capacity from 300,000 barrels per day to 890,000 barrels per day.

Kinder Morgan advocated an expansion of the existing pipeline as part of a broader effort to ship more of Canada’s oil to the Asia-Pacific region via its Westridge Marine Terminal in Burrard Inlet, Burnaby. The company has argued that Canada stands to gain an additional $3.7 billion each year from shipping greater quantities of oil across the Pacific Ocean than it would from selling oil to US markets.

The project has faced political and legal hurdles at the federal and provincial levels. Within a year of the expansion proposal, dozens of protesters were arrested on Burnaby Mountain for attempting to block pipeline survey work. The federal government intervened to ensure a thorough environmental review was conducted. It approved the project in 2016.

More than 150 anti-pipeline activists — including Green Party leader Elizabeth May and NDP MP Kennedy Stewart — were arrested in March 2018 during demonstrations at Kinder Morgan facilities in Burnaby. (An order from the BC Supreme Court prohibited protesters from approaching within 5 m of construction zones at two Burnaby terminals owned by the company.)

Trans Mountain pipeline protest
Police arrest a protester at a rally against the Trans Mountain Expansion in Burnaby Mountain Park, 20 November 2014.

In early 2018, a trade dispute erupted between BC and Alberta, after BC’s NDP government under ​John Horgan proposed a ban on increased shipments of bitumen from Alberta to the West Coast while it sought further consultation on the risks of oil spills. Alberta NDP premier Rachel Notley responded that such a decision was unconstitutional and violated trade rules. She also retaliated by temporarily halting the import of BC wine to her province. The feud escalated into the spring. Alberta passed a bill that threatened to prevent its existing oil exports from reaching BC, to which BC responded with a lawsuit.

Kinder Morgan suggested that it would be forced to abandon the Trans Mountain Expansion if it did not receive “clarity on the path forward” and assurances for its shareholders by 31 May. Amid mounting pressure from Canadian business leaders to get the pipeline built, Prime Minister Justin Trudeau interrupted a trip abroad for an emergency meeting with the two premiers. The federal government also promised to compensate Kinder Morgan for financial losses resulting from construction delays.

The dispute remained at an impasse. Two days before Kinder Morgan’s deadline, the federal government announced that it would buy the existing pipeline for $4.5 billion and seek new investors to complete the expansion project. Notley and some business leaders celebrated the decision, but politicians across the political spectrum criticized it as a misuse of tax dollars. Some opponents also branded the deal as a failure to instill confidence in investors and to solve the political problems plaguing the project, while others saw it as a betrayal of the Liberals’ commitments to environmental action and Indigenous rights.

On 30 August 2018, the Federal Court of Appeal ruled on lawsuits that six First Nations, the City of Vancouver, the City of Burnaby and two environmental groups launched against the Trans Mountain Expansion Project after it received government approval in 2016. The court found that the federal government failed in its duty to “engage in a considered, meaningful two-way dialogue” during consultations with First Nations on the expansion. It also concluded that the NEB “unjustifiably excluded” marine shipping from its definition of the project. According to the court, this meant that the NEB failed to consider its obligations, under the Species At Risk Act, to propose measures to lessen the impact of oil-tanker traffic on endangered killer whales. The ruling overturned the federal government’s approval of the expansion and ordered it to redo parts of the consultation and approval process.

Edmonton mayor Don Iveson, Calgary mayor Naheed Nenshi and United Conservative Party leader Jason Kenney expressed disappointment at the decision. Premier Notley announced that Alberta would withdraw from the national carbon pricing plan until the federal government clears the way for construction to begin.

The day after the Federal Court of Appeal released its decision, Kinder Morgan completed its sale of the Trans Mountain pipeline and expansion project to the Government of Canada.

In February 2019, the NEB released its reconsideration report on the expansion project, the reassessment ordered by the Federal Court of Appeal the previous year. The agency once again recommended that the project be approved, concluding that it was in the national interest. The NEB made 16 new recommendations to the government for measures to “mitigate, avoid, or lessen the effects of Project-related marine shipping.”

Prime Minister Trudeau’s Cabinet approved the expansion for the second time in June 2019. The government intends to sell the project, and it has specifically encouraged Indigenous investors. It expects construction to begin before the end of 2019.

TC Energy Keystone XL

TransCanada Keystone XL pipeline (proposed)

Keystone XL is a 1,897 km long crude oil pipeline project first proposed by Calgary-based TC Energy Corporation in July 2008. The 36-inch-diameter pipeline, dubbed XL for “export limited,” is the fourth phase of TC Energy’s Keystone Pipeline system that currently ships up to 591,000 barrels of crude oil per day from Alberta to refineries in Illinois and Texas.

Keystone XL would cross the Canada-US border en route from Hardisty, Alberta to Steele City, Nebraska, adding an additional 830,000 barrels of oil per day capacity and, proponents contend, US$3.4 billion to the United States’ GDP. Economic benefits to Canada — and Alberta in particular — from salaries, wages and property taxes are also cited.

The project has drawn significant opposition from environmental groups, ranchers, and numerous Indigenous communities in Alberta, Montana and Nebraska. Many fear the additional crude oil shipped by the pipeline could pollute lands and rivers. In the context of the Keystone XL debate, James Hansen, climatologist and former director of the NASA Goddard Institute for Space Studies, said in 2012 that if Canada’s oil reserves were fully tapped, the amount of carbon emitted into the atmosphere would mean “game over for the climate.”

Because Keystone crosses the Canada-US border, the expansion requires US State Department approval to proceed. Keystone XL’s permit was rejected by US president Barack Obama in 2015. On 24 March 2017, President Donald Trump issued a presidential permit approving the project. TC Energy’s efforts to secure the various additional permits and approvals needed to begin construction hit a major roadblock in November 2018, however, when a federal judge in Montana halted the project. The judge ordered that the State Department complete a more thorough environmental assessment before work on Keystone XL can continue.

Enbridge Line 3 Replacement Project (part of Enbridge Mainline)

Enbridge Line 3 Replacement Project pipeline (under construction)
Enbridge Line 3 Pipeline
Hardisty, Alberta, 10 August 2017.

The Line 3 Replacement Project (also known as the L3RP) is a 1,660 km long proposed upgrade to an existing crude oil pipeline running from Hardisty, Alberta to Superior, Wisconsin. It’s the largest energy infrastructure project ever undertaken in the history of Calgary-based company Enbridge.

Expected to be in service in 2019, the L3RP project will upgrade 34-inch-diameter pipes to 36-inch-diameter pipes and allow for 760,000 barrels of light, medium and heavy crude oil to flow to the Superior Station and Terminal Facility in Wisconsin daily. Canadian upgrades are expected to cost CA$5.3 billion, while US upgrades are expected to cost US$2.9 billion.

The NEB held hearings on the replacement project in November and December 2015. On 29 November 2016, the Canadian government announced its approval. While the decision was hailed by proponents such as the United Steelworkers union and Saskatchewan premier Brad Wall, some environmental groups suggested the Canadian government would be better to invest in renewable energy than approve pipeline expansions. The Federation of Sovereign Indigenous Nations chief Bobby Cameron urged the need for “stringent protections for the environment.”

Enbridge began construction on 1 August 2017. Most of the work on the Canadian portion of the pipeline is complete. Construction of the Minnesota portion has hit several delays. In June 2019, the Minnesota Court of Appeals ruled that the project’s environmental assessment failed to consider the impact of a potential oil spill in the Lake Superior watershed. It ordered further reviews by state regulators before construction can continue.

Enbridge Northern Gateway

Enbridge Northern Gateway pipeline (cancelled)

The $7.9 billion Northern Gateway project from Enbridge was a pipeline first proposed in 2008. It was projected to carry diluted bitumen approximately 1,170 km from Bruderheim, Alberta to a terminal on the Pacific Ocean at Kitimat, British Columbia. Enbridge claimed the project would generate $1.2 billion in tax revenue for BC, in addition to 560 jobs.

An estimated 220 oil tankers were expected to cross the turbulent waters around the Great Bear Rainforest en route to the Pacific, ferrying some of the 525,000 barrels of dilbit shipped each day to the terminal at Kitimat. Many feared marine spills in the difficult-to-navigate waters of the Douglas Channel were inevitable, threatening vital habitat for fin whales, killer whales and humpback whales (see also Water Pollution).

The NEB held public consultations on the project spanning 180 days from 2012 to 2013. The overwhelming majority of those who testified at the hearings voiced opposition to the project. Its critics included First Nations, environmental groups, the Union of British Columbia Municipalities and a labour union, Unifor. In June 2014, Prime Minister Stephen Harper approved the pipeline, two months after Kitimaat, the home community of the Haisla Nation, voted against it.

In late 2015, the Federal Court of Appeal heard legal challenges against Northern Gateway launched by eight First Nations, a coalition of four environmental groups led by Ecojustice, and Unifor. The suit claimed the project’s environmental assessment was incomplete.

Months after the BC Supreme Court ruled that the provincial government had “breached the honour of the Crown by failing to consult” with the Gitga’at (see Tsimshian) and other First Nations on Northern Gateway, in January 2016, Prime Minister Justin Trudeau confirmed that his government would not support the project.

Mackenzie Gas Project

Mackenzie Valley pipeline (part of the cancelled Mackenzie Gas Project)
Beaufort Sea
Artificial island in the shallow waters of the Mackenzie Delta, Beaufort Sea.

First proposed in the 1970s, the Mackenzie Valley pipeline (later known as the Mackenzie Gas Project) was intended to ship natural gas from the Mackenzie River delta in the Beaufort Sea through Inuvialuit, Gwich’in, Sahtu and Deh Cho regions of the Northwest Territories into Alberta. The project was postponed for a decade and then indefinitely, as Indigenous land claims and ownership structures of resource infrastructure were agreed to throughout the 1980s and 1990s.

In 2004, Calgary-based Imperial Oil petitioned the NEB for permission to construct a $16.2 billion pipeline to ship up to 34.3 million cubic metres of natural gas approximately 1,200 km each day to Alberta. The NEB approved the project in 2010 and gave Imperial Oil and its partners until 31 December 2015 to begin construction.

In August 2015, Imperial Oil requested the NEB give it until 2022 to begin construction, claiming it needed more time to determine whether North America’s natural gas market was robust enough to make building the pipeline worthwhile. Some Indigenous groups, including the Inuvialuit Regional Corporation, the Gwich’in Tribal Council and the Tulita District Land Corporation, publicly supported the project and the proposed extension. The first two of these organizations, along with the Sahtu Pipeline Trust, partnered in the initiative as the Aboriginal Pipeline Group.

Environmental groups argued against the extension, citing shifts in energy markets, increased climate-change awareness and a change in federal government since the project was approved in 2010. One such group, Alternatives North, suggested the downstream greenhouse gas implications of the pipeline should ultimately rule out its construction.

In June 2016, the NEB claimed the Mackenzie Gas Project was still in the public interest and granted Imperial Oil and its partners until 2022 to begin construction or risk forcing another environmental assessment on the project. In December 2017, however, the partnership announced that it had cancelled its plans for the pipeline.

Pipelines in Canada // Key Terms

Fossil fuels

Naturally occurring fuels such as coal, oil and gas formed beneath Earth’s surface. Over millions of years, plants and animals have decomposed into organic chemical compounds, called hydrocarbons, that make up these fuels.

Crude oil (or petroleum)

Unrefined hydrocarbon oil that is extracted from the earth to process for various human uses.


Thick, dark mixtures of hydrocarbons sourced in the earth or in the process of refining petroleum.

Diluted bitumen (“dilbit”)

Bitumen that has been diluted with lighter types of petroleum so that it will flow through pipelines.

Natural gas

Gas sourced beneath Earth’s surface, composed of mixtures of hydrocarbons such as methane. It is called liquefied natural gas when it has been converted to liquid for transportation or storage.

Greenhouse gases

Gases that trap heat in the atmosphere. There are several different types of greenhouse gases, but two in particular are responsible for climate change: carbon dioxide (CO2) and methane (CH4).

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