TransCanada Corp has entered into agreements to sell a 25% interest in each of Gas Transmission Northwest (GTN) and Bison Pipeline (Bison) to TC PipeLines for $605m.

GTN is a 1,353-mile pipeline system that transports western Canada Sedimentary basin and Rocky Mountain-sourced natural gas to third party gas pipelines and to the markets in Washington, Oregon and California in the US.

This pipeline has a design capacity of 2.9 billion cubic feet per day (bcf/d) and is supported by long-term contracts for 1.5bcf/d that mature between 2015 and 2028.

Bison is a new 303-mile natural gas pipeline connecting Rocky Mountain gas supply to downstream markets via the Northern Border pipeline system.

TC PipeLines plans to initially fund the acquisition through a $400m bridge loan facility and the balance drawn from its $250m senior revolving credit facility.

The transaction is expected to close in May this year and is subject to certain closing conditions.