TransCanada’s 100 per cent owned 14,101 km natural gas transmission system in Canada extends from the Alberta/Saskatchewan border east to the Québec/Vermont border and connects with other natural gas pipelines in Canada and the U.S.

In 2008, annual deliveries of natural gas on the Canadian Mainline totalled 3,467 billion cubic feet (Bcf) – representing an average of 9.5 Bcf/day. This compares to deliveries of 3,183 Bcf (averaging 8.7 Bcf/day) in 2007.

The Canadian Mainline is regulated by the National Energy Board (NEB). The NEB sets tolls which provide TransCanada the opportunity to recover projected costs of transporting natural gas and provide a return on the Canadian Mainline’s average investment base. New facilities are approved by the NEB before construction begins. Changes in investment base, the rate of return on common equity, the level of deemed common equity and the potential for incentive earnings.