How well do you know your pipes?

Life in Canada would be very different without highways, water and sewage systems or electrical transmission lines. These systems are critical to the high standard of living Canadians enjoy. Pipelines are also part of this critical infrastructure, but because we often don’t see them, we sometimes take for granted the role they play in our lives.

The pipelines that deliver energy around the country serve different purposes. This blog post is designed to help you understand the types of pipelines that are part of Canada’s pipeline infrastructure.

The difference between liquids pipelines and natural gas pipelines

Liquids pipelines: Crude oil and natural gas liquids (NGLs) get from producing fields to refineries through liquids pipelines. Product is pushed through the line by pumps located along the pipeline route. Crude oil, for example, moves through the pipe at around five kilometres per hour (roughly walking speed).

Natural gas pipelines: Natural gas, on the other hand, is transported by a different kind of pipeline system. Natural gas is kept moving through a pipeline thanks to compressor stations.

“The gas comes in at a low pressure, goes through compressors, (and) the gas is compressed and pushed out at a higher pressure,” explained Larry Hunt, director of integrity with Spectra Energy Transmission – West, one of our member companies that operates natural gas pipelines.

The difference between gathering lines and transmission pipelines

For natural gas, gathering lines bring raw natural gas from areas where wells are located to processing plants. At the plants, the raw gas is cleaned*. From the processing plants, large transmission pipelines deliver the natural gas hundreds of kilometers to distribution companies. Local distribution companies have their own lines to deliver the natural gas to homes and businesses.

“We have lines that run from three inches in diameter to 26 inches in diameter for the gathering systems. Our transmission pipelines start at 26 inch and go up to 42 inch,” said Hunt, who added that natural gas gathering lines could be a few kilometres long to around 60 kilometres long.

Hunt’s job is to ensure the integrity of both the gathering lines and the transmission pipelines are maintained.

“There are people who live around gathering lines and there are people who live around transmission lines, and we have a responsibility to make sure they’re all safe,” he stressed.

For crude oil, many small gathering lines are used to “gather” crude oil from wells and move the product to oil batteries. Large transmission pipelines then move the crude to refineries. Once the oil reaches a refinery, it is turned into the products we use everyday such as gasoline, jet fuel and diesel.

Check out our “Types of Pipelines” page for a comprehensive breakdown of the different lines.

*Some natural gas processing plants extract NGLs such as ethane, propane and butane, which are then transported by liquids pipelines.

Where does CEPA fit in?

CEPA represents both natural gas and liquids transmission pipeline companies. Transmission pipelines are Canada’s energy highways because they move large amounts of product over long distances (sometimes over international borders). These pipelines ensure energy travels safely from areas where it is produced to areas where it is most needed.


The Canadian Energy Pipeline Association represents Canada’s transmission pipeline companies who operate approximately 115,000 kilometres of pipelines in Canada. In 2012, these energy highways moved approximately 1.2 billion barrels of liquid petroleum products and 5.1 trillion cubic feet of natural gas. Our members transport 97 per cent of Canada’s daily natural gas and onshore crude oil from producing regions to markets throughout North America.