TransCanada Corp. has been chosen to build a $4-billion natural gas pipeline to the British Columbia coast to feed a massive export project planned for construction at Kitimat.

The Coastal GasLink project will run 700 kilometres from near Dawson Creek, B.C., and will feed the liquefied natural gas terminal under design by Royal Dutch Shell Plc., Mitsubishi Corp., Korea Gas Corp. and PetroChina Company Ltd.

On Tuesday, TransCanada said the pipe will be able to carry up to 1.7 billion cubic feet a day, will take two to three years to build, and could enter service by the end of the decade, the rough timeframe for construction of the LNG terminal.

The need to build large new pipelines to the coast to service LNG facilities has drawn substantial competition, with Spectra Energy Corp. and Enbridge Inc. both publicly expressing interest in participating.

The win for TransCanada is an important one. The company is currently battling for the survival of its Mainline, the massive gas pipeline that crosses the country and delivers western gas to central and eastern markets. Gas volumes on the Mainline have plummeted, and a key risk going forward is the likelihood that LNG projects will divert supplies west, rather than east.

By gaining ownership of a pipeline west, TransCanada maintains a large interest in movements of Canada’s natural gas. It may also gain a critical foothold allowing it to service other future LNG projects, given the half-dozen proposals that various corporate groups are pursuing for Kitimat and nearby Prince Rupert.

TransCanada’s presence could also be a boon for natural gas companies in Alberta, whose product largely travels on existing TransCanada pipes. TransCanada said Tuesday that it intends to tie the Kitimat pipeline to its Alberta system, with a proposed pipe extension to Vanderhoof, B.C. that would give Alberta companies access to potentially lucrative export markets.

TransCanada “expects to elicit interest in and commitments for such service through an open season process in late 2012,” the company said in a release.

“Our team has the expertise to design, build and safely operate pipeline systems,” said TransCanada chief executive Russ Girling in a statement. “Coastal GasLink will add value to British Columbians, particularly Aboriginals and communities along the conceptual route, by creating real jobs, making direct investments in communities during construction and providing economic value for years to come.”