The natural gas consumed in Québec is distributed from gas hubs. To reach Québec, natural gas is transported over long distances by the networks of TransCanada PipeLines, Union Gas, TQM, Énergir and Champion Pipeline. This is the transmission network. The steel pipelines for this type of network are the largest and transport the natural gas under high pressure that is 20 to 50 times greater than that of a car tire.
The transmission network is then routed to a delivery station where the pressure is decreased and an odorizer called mercaptan is added to it, making it easy to smell the natural gas in the air. The natural gas leaves the delivery station in supply lines. These lines are 10 to 20 cm in diameter and operate at a pressure level 10 times that of a car tire. This is the supply network.