Read the updated story: Feds spending $4.5B to buy Trans Mountain pipeline

The federal government will announce its decision Tuesday morning that the Trans Mountain pipeline will move forward -- with public money on the table.

Finance Minister Bill Morneau will announce his decision in a press conference early Tuesday morning before financial markets open.

The announcement will come just two days before the May 31 deadline set by Kinder Morgan to decide if it’s confident enough to proceed with construction.

It remains unclear how Ottawa plans to finance the controversial project, but three options are on the table.

The first and most likely option: the federal government buys and builds the Trans Mountain pipeline expansion. Ottawa has expressed interest in starting construction as soon as possible to take advantage of the brief summer construction season. Once the pipeline is built, the government would then try to sell it to new investors – putting Kinder Morgan out of the picture.

The second option would also involve the government buying the expansion, and then selling it to investors. Investors would then be responsible for the pipeline’s construction.

Morneau has already openly discussed the third option: Kinder Morgan going ahead with the project, with Ottawa covering any losses incurred.

Morneau is expected to detail the federal government’s plan and confirm a price tag in the announcement.

Shortly before the announcement, Morneau will brief his fellow cabinet ministers on the decision at 7:30 a.m.

Prime Minister Justin Trudeau has repeatedly pledged to get the project built. Alberta Premier Rachel Notley and British Columbia Premier John Horgan have been at odds over the pipeline.

B.C. fears that a pipeline spill would be devastating for the coast, while Alberta insists that the expansion -- which already has federal approval -- is in the best interest of the Canadian economy.

The interprovincial spat between the two NDP premiers prompted Alberta to briefly cut off B.C. wine imports and threaten to turn off the oil taps. In response, B.C. has gone to the provincial Court of Appeal to see if it has jurisdiction to regulate heavy oil shipments.

Protests have taken place across Canada both for and against the pipeline. On Monday, Green Leader Elizabeth May was ordered to pay a $1,500 fine for her involvement in an anti-pipeline rally at a main gate to Kinder Morgan's pipeline terminal.

The expansion would triple the amount of oil transported from Edmonton to Burnaby, B.C., from 300,000 barrels a day to 890,000 barrels a day. The Trans Mountain pipeline has been in operation since the 1950s.

With a report from CTV’s Ottawa Bureau Chief Joyce Napier

On the Hill for ins at 7:30 am cabinet meeting. Morneau announcement on TMX at 8 am. Timing likely dictated by market open.(These construction guys do this every day.) pic.twitter.com/Km4FFdpqTe — Glen McGregor (@glen_mcgregor) May 29, 2018

In advance of today's TransMountain announcement, PMJT advisor @gmbutts is Insta-quoting Civil War general on leadership. [Insert your own comment here] pic.twitter.com/2Up9Om0Ohz — Glen McGregor (@glen_mcgregor) May 29, 2018

Environment Minister Catherine McKenna has nothing to say about possible federal purchase of TransMountain pipeline. pic.twitter.com/QJavW3FfgJ — Glen McGregor (@glen_mcgregor) May 29, 2018

Finance minister Bill Morneau also offering nada on TransMountain on his way to brief cabinet before 8 am presser. pic.twitter.com/ilvaVJtKIn — Glen McGregor (@glen_mcgregor) May 29, 2018