Enbridge Inc. is moving forward with a controversial plan that involves long-term commitments to ship oil on its Mainline pipeline system.   

The pipeline company submitted an application to the Canada Energy Regulator Thursday to set aside 90 per cent of capacity on the pipeline to shippers who sign long-terms contracts.

"We are moving to a contracted Mainline system in response to what our customers have been asking us for and for the benefit of the entire industry," Enbridge Executive VP of Liquids Pipelines Guy Jarvis said in a release.

"Today's application is based on significant input and advice from every corner of our industry and almost two years of extensive negotiation with shippers to recognize the needs of various customers in a balanced way."

The plan has previously drawn opposition from Canadian energy giants such a Suncor Energy Inc., Canadian Natural Resources Ltd. and Shell Canada. The CER shut down Enbridge's initial attempt at open season for long-term contracts after the industry outcry.

“I think it’s one of those unique dynamics where it plays into some of the broader trade and broader protectionist aspects as well,” said Nathan Thooft, head of global asset allocation at Manulife Investment Management, on BNN Bloomberg Friday.

“You have a situation where there’s no doubt that there’s some companies on the other side of the border that may favour this, versus others on the Canadian side where the regulators probably want to be a little more sensitive to what’s going on with Canadian companies and the impacts specifically to them.”

Enbridge’s Mainline system includes five pipelines that begin in Edmonton and cross the Canada-U.S. border near Gretna, Man, where it operates in the U.S. as the Lakehead system.

The current cross-border capacity of the Mainline is approximately 2.9 million barrels per day.