If approved, the 1,200-kilometre Mackenzie Valley pipline could be built to transport natural gas from the Beaufort Sea through the N.W.T.'s Mackenzie River Valley to a hub in northwestern Alberta. (CBC)

The National Energy Board will say Thursday whether it will approve the long-awaited Mackenzie Valley natural gas pipeline in the Northwest Territories.

The federal energy regulator will release its decision on whether or not Imperial Oil and its partners will be granted a "certificate of public convenience and necessity" to build the $16.2-billion pipeline.

The NEB will post its decision on its website at 2:30 p.m. MT (4:30 p.m. ET) on Thursday, according to an advisory issued on Wednesday.

Copies of the NEB report will also be available at the board's office in Calgary, at the Yellowknife Public Library and at the Inuvik Centennial Library in Inuvik, N.W.T.

If approved, the 1,200-kilometre pipeline could move at least 1.4 billion cubic feet of natural gas a day from the Inuvik area, through the Mackenzie River Valley south to a hub in northwestern Alberta, where it would connect with existing networks.

The natural gas would come from three "anchor fields" located near the Beaufort Sea in the Mackenzie Delta.

Six-year review process

Calgary-based Imperial Oil is the lead company in the consortium that is spearheading the pipeline. The consortium also includes Exxon Mobil Corp., ConocoPhillips, Royal Dutch Shell PLC and the Aboriginal Pipeline Group.

The NEB has been reviewing the pipeline proposal since 2004, when the consortium submitted its application.

Around the same time, an independent joint review panel was created to consult northerners about the environmental and socio-economic impacts of the proposed pipeline.

The panel released its report Dec. 30, 2009, approving the project as long as its 176 recommendations were followed by the pipeline proponents and the federal and N.W.T. governments.

The panel's report was submitted to the NEB, which held its final round of hearings earlier this year.

Anxiously awaiting decision

Pipeline supporters and critics alike have been waiting years for the NEB decision. People in the Inuvik area — where the pipeline route would begin — have been especially anxious for word on whether the project will become a reality.

"In 1997, when I got into this business … I got into it due to the oil and gas and the pipeline coming," said Kurt Wainman, owner of Northwind Industries, a construction and heavy-equipment company in Inuvik. "And you know, it's 13 years later, and I'm still waiting for a pipeline announcement and a go-ahead.

"In the meantime, I've been building my infrastructure up to accommodate everything, and now, I am actually downsizing just to stay alive and wait for the pipeline."

A green light from the NEB does not mean construction would start right away. It would then be up to the federal cabinet to make a final decision.

As well, Imperial Oil has until Dec. 31, 2013, to make a final decision on whether to proceed with the pipeline at all, although it has asked the NEB for three more years to decide. The board is expected to rule on whether to grant the company more time.

Should the company decide by 2013 to go ahead, construction would start in 2014 and production would start in 2018.