Pipelines are pipes, usually underground, that transport and distribute fluids. When discussing pipelines in an energy context, the fluids are usually either oil, oil products and natural gas. If hydrogen fuel gets extensively developed, pipelines will be needed to transport this secondary fuel. Outside of an energy context, pipelines transport other fluids like water. Oil and gas pipelines form extensive distribution networks—providing about 825 000 kilometers of lines in Canada to transport natural gas, liquefied natural gas products, crude oil, and other refined petroleum products. These lines vary in diameter depending on their use, and are generally located underground.
Within the energy sector, there are two major types of pipelines, liquids pipelines and natural gas pipelines. Liquid pipelines transport crude oil or natural gas in liquid form to refineries where they undergo distillation and other production processes. Some liquids pipelines are also used to transport distilled petroleum products such as gasoline to distribution centers. Natural gas pipelines are used solely for the transport of natural gas to processing plants and are used for distribution. Natural gas is also often delivered directly to homes through pipelines. In addition to these two main types of pipelines, there are also four other sub-categories of pipelines:
For liquid pipelines that transport crude oil and liquefied petroleum products, small diameter gathering lines collect the product from where it is extracted. After moving to a gathering facility, it moves to feeder pipelines with relatively large diameters which transports product to refineries. Transmission lines are used when oil and liquids have to travel long distances. To push the liquid through the pipe, powerful pumps are used and move oil at around walking speed. Liquids pipelines are very versatile and can transport a variety of grades or varieties of crude oil and crude oil products.
The process is similar for natural gas pipelines—extracted natural gas is transported for processing in gathering and feeder lines, then moves into large transmission pipelines (generally composed of steel pipe). Gas is able to flow as it moves from areas of high pressure to low pressure. This pressure difference is obtained through the use of compressors that increase the pressure of the gas, pushing it along. Once the gas reaches a distribution plant, companies reduce the pressure of the gas and distribute it through small distribution pipelines.
Although they are a necessary part of the use and transportation of assorted petroleum products, there are environmental concerns with the construction and operation of pipelines that vary depending on how and where the pipelines are being built. Some of the concerns include:
Pipelines have been constructed extensively for many years and thus there are numerous steps taken to minimize any environmental effects. The environmental impacts cannot be avoided entirely, only reduced. Although these issues are all concerning, most people are concerned with a rupture in a pipeline and a spill. A spill of petroleum products can cause significant environmental damage and pose a risk to human health—as they can burn, contain toxic chemicals, and pollute groundwater. However, pipeline ruptures are not extremely common, but they do occur. Older pipelines are much more vulnerable to rupture as a result of corrosion. Although large scale ruptures do not occur frequently, there were 758 small scale ruptures in Alberta pipelines between 1990 and 2005 with fewer occurring each year. Even small spills can affect the environment, but the impacts vary drastically depending on where the spill occurs. Large scale ruptures release between 1000 and 10 000 cubic meters of liquids and do not occur as frequently.
As was discussed above, Canadian pipelines are not only varied in what they can carry but expansive. Below are two different maps showing the paths of different Canadian pipelines, both for liquid and gas transport. Note how expansive these pipelines are, and how many cross either provincial or national borders. Figure 2 shows a map of large Canadian and American liquid and gas pipelines.