(Bloomberg) —President Donald Trump’s decision to revive TransCanada Corp.’s Keystone XL pipeline may herald a new era of pipeline abundance for Canadian oil producers after years of bottlenecks.

The U.S. president signed documents to advance the project Tuesday, more than a year after his predecessor Barack Obama rejected it on grounds it would contribute to climate change. The decision follows the Canadian government’s approval in November of Kinder Morgan Inc.’s Trans Mountain line to the Pacific and Enbridge Inc.’s expansion of Line 3 to the U.S. Midwest.

The three lines would add 1.8 million barrels a day of crude export capacity, enough to handle Western Canada’s growing oil production for 20 years, according to National Energy Board projections.

That would add more than $4 billion a year to Western Canada’s economy by making the region’s crude more valuable relative to other grades, Tim Pickering, founder and chief investment officer of Auspice Capital Advisors Ltd. in Calgary, said in a phone interview. Because of the lack of capacity, refiners haven’t paid as much for Canadian crude.

“Too much capacity is not a big concern for the Canadian marketplace and producers right now,” Pickering said. “It gives us room down the road to increase production.”

Big Discounts

Canadian oil producers such as Suncor Energy Inc., Cenovus Energy Inc. and Imperial Oil Ltd. have sold their heavy crude at discounts to West Texas Intermediate futures of as much as $40 a barrel in recent years amid constraints in pipeline space. Western Canadian Select’s discount to WTI averaged about $14 a barrel over the past year, data compiled by Bloomberg show. That may shrink to $5 to $7 a barrel should all three lines get built, Pickering said.

More pipelines from Canada would also “generate greater competition for crudes of comparable quality such as those imported from Mexico or Venezuela,” Harry Tchilinguirian, head of commodity-markets strategy at BNP Paribas SA in London, said in an instant message.

The administration moved to expedite approval and construction of the Keystone XL pipeline as well as the Dakota Access line through North Dakota. Trump said he wanted to renegotiate terms to get a better deal for the U.S., including more U.S.-made materials in the lines.

The 830,000-barrel-a-day Keystone XL has been blocked since it was first proposed in 2008. TransCanada said in a statement it will reapply for the project.

‘Better Netbacks’

The approval of Keystone XL and other lines “will mean better netbacks to producers,” Tim McMillan, chief executive officer of the Canadian Association of Petroleum Producers, said in a phone interview Tuesday. “It’s really just a more efficient system for our economy.”

Kinder Morgan’s TransMountain line and Enbridge’s Line 3 are scheduled for completion by the end of the decade, both companies have said.

Trans Mountain, which still faces at least two legal challenges, has the added advantage of opening up access to Asian markets for Canadian crude. Canada now sells nearly all its oil to the U.S.

“Our view has been first of all that we need to diversify our markets, we can’t rely on one market and one market only,” Alberta Premier Rachel Notley told reporters in Edmonton Tuesday.

TransCanada has declined to comment on the timing of construction. In a best-case scenario, work could start this year, Dennis McConaghy, former executive vice president of corporate development at the company and a current shareholder, said by phone.