The expansion of the system requires a $570m by 2018, the company said.

The contracts are intended to address the growth in unconventional natural gas supplies in northwestern Alberta and northeastern British Columbia in Canada.

TransCanada president and CEO Russ Girling said: "Our NGTL System is sitting on top of extensive natural gas supplies, making it well-positioned to unlock the resource and reliably and efficiently link it to growing markets."

The NGTL System expansion program is a part of TransCanada’s $48bn capital growth plan which includes $23bn investment in new natural gas pipelines.

The company said that the expansion program would boost the overall investment on the NGTL System beyond the $7.5bn of projects that were previously announced.

Of these projects, regulatory approval was granted to about $2.8bn of projects, with $800m under construction, and an additional $1.7bn of facilities under review.

As part of the expansion program, TransCanada will undertake multiple projects including 88km of 20- to 48-inch diameter pipeline, one new compressor as well as about 35 new and expanded meter stations and other associated facilities.

The company also plans to file applications with the National Energy Board between the second quarter and the fourth quarter of 2016 to construct and operate different components of the expansion program.

Construction work, which is subject to regulatory approvals, is planned to commence in 2017 while all facilities are scheduled to be commenced in 2018.

TransCanada recently secured a contract to build, own and operate the $500m Tuxpan-Tula Pipeline in Mexico.

Image: TransCanada plans to invest $23bn in new natural gas pipelines. Photo: courtesy of bejim/FreeDigitalPhotos.net.