Premier Christy Clark says that while it was courageous for her Alberta counterpart to travel to British Columbia to argue in favour of the Trans Mountain pipeline expansion, it's ultimately up to Prime Minister Justin Trudeau to explain his government's approval of the project.

Ms. Clark said Alberta Premier Rachel Notley did the right thing when she spent two days in the province defending the pipeline, which would run from Edmonton to the Vancouver region, and now it's time for Mr. Trudeau to do the same.

"It was his approval. And I think he is going to want to make sure he comes out to British Columbia and talks to people about his reasons for approving it," she said Wednesday.

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Mr. Trudeau, however, has yet to make plans to visit B.C. and his office was non-committal when asked whether he planned to make a trip to sell the pipeline.

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The Prime Minister's press secretary noted that Mr. Trudeau has visited B.C. on several occasions this year, including the early November announcement in Vancouver of the ocean-protection plan.

"He will continue to visit the province on a regular basis as he has been doing throughout his mandate," Cameron Ahmad said in a statement though he did not specify the date of Mr. Trudeau's next visit.

Premier Clark's comments came a day after Ms. Notley wrapped up a two-day visit to Vancouver in which she made the case for Kinder Morgan's proposed expansion of the Trans Mountain pipeline, which she sees as a necessary project for getting Alberta oil to Pacific Rim markets.

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The NDP Leader from Alberta met with the media and B.C. NDP Leader John Horgan, who strongly opposes the pipeline expansion as an environmental risk to the region.

The federal government intensified a feisty debate in British Columbia with its decision last week to allow the proposed expansion which critics have said raises the risk of a spill in Vancouver-region waters given the intensified tanker traffic that will be required.

Environmentalists, some Lower Mainland mayors and First Nations leaders are united in opposition to the project, and there is the prospect of massive protest ahead.

Ms. Clark saluted Ms. Notley's defence of the project. "I think Rachel Notley did the right thing," she said. "It takes courage to come in and defend your point of view and defend your province outside your own borders."

In Edmonton, Ms. Notley said the B.C. outreach was the best possible "good start" that could be arranged on relatively short notice.

"I was pretty pleased with the degree to which we were able to inject some of the other facts and, maybe, bring down the intensity a little bit, but talk about the merits," Ms. Notley said.

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Ms. Notley, who will meet with Ms. Clark in Ottawa during this week's first-ministers' meeting, said her reception seemed "fairly reasonable" with fair coverage of the Alberta side of the issue.

During her visit, Ms. Notley touted economic benefits associated with the Trans Mountain project, including positive impacts on B.C.'s gross domestic product. According to a spokesperson, some came from a 2012 Conference Board of Canada study on the project.

That study is entitled Who Benefits? A Summary of Economic Impacts That Result From the Trans Mountain Expansion Project.

But critics were dismissive of those benefits.

"Premier Notley expressed the upside in a frame that favours her argument. The truth is the risk to our marine-life economy, to fisheries, to tourism in British Columbia is huge," George Heyman, the B.C. NDP critic for the environment, green economy and technology, said on Wednesday.

He acknowledged construction jobs associated with the project, but said there are "more productive" construction needs for the province such as in the renewable energy sector, including retrofitting public buildings for energy efficiency.

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Meanwhile, the director of the industrial economic trends group at the Conference Board offered some caveats to its research on benefits of the pipeline.

Michael Burt said these include assumptions about the economy as it existed when research was carried out, and the fact that the economy has the workers and the materials to facilitate construction.

An updated 2015 study on the project, building on 2012 research, suggests it would generate 33,900 jobs and $925-million in fiscal benefits per year over the first 20 years of operations. Of that, Alberta would get 55 per cent of employment benefits and 41.5 per cent of fiscal benefits while B.C. would get 23.6 per cent of employment impact and 12.1 per cent of fiscal benefits.

Mr. Burt said he was pleased that a prominent Canadian leader was referring to board research. "Certainly we're happy that it's helping to inform policy makers," he said.

With a report from Justine Hunter in Victoria