A report commissioned by Alberta says oilsands producers could lose up to $72 billion if a pipeline isn't built to ship heavy crude to the British Columbia coast.

The report by consultants Wood Mackenzie has been submitted by the province to the federal panel reviewing Enbridge's proposed Northern Gateway project.

The report says that without such a pipeline, oilsands companies would not have access to ship their increasing bitumen production to growing Asian markets, especially China.

That means more bitumen would have to be shipped to U.S. refineries at a lower price.

"Given a current lack of access to key demand centres, and the lengthy lead time required to execute a pipeline project and the projected growth in supply, the timing of a West Coast export capacity option is critical," reads the report.

"Our assessment of producers not having access to the Asian markets through a West Coast tidewater option suggests producers are likely to lose about $8/bbl (lost revenue of $8 billion per year for 2017 to 2025.)"

Public hearings into the $5.5-billion Northern Gateway project are to begin in Kitimat, B.C., next Tuesday.

Two pipelines proposed

Enbridge wants to build two 1,170-kilometre-long pipelines from Bruderheim, Alta., to an oil tanker port to be built near Kitimat.

One of the pipelines would be used to ship up to 525,000 barrels of oilsands bitumen a day to the coast for export. The other would be used to ship up to 193,000 barrels of light oily material daily to Alberta. The substance is used to thin heavy oil so it can easily pass through pipelines.

The Wood Mackenzie report suggests the industry could face a shortage of this toxic material, known as condensate, as oilsands production ramps up.

More than 4,000 people have signed up to speak at the review panel hearings in two dozen communities in B.C. and Alberta.

Tim Markle, a spokesman for Alberta's Energy Department, said provincial government representatives are to appear before the panel later this year to formally present the report and make other submissions.

Markle said people should not consider Alberta's position as specifically endorsing Northern Gateway. He said the province would support any project that would help increase oilsands exports, including other pipelines or shipping bitumen by rail.

"Access to newer markets, especially to those in the Pacific Rim, are an advantage to Alberta and the producers and basically to all of Canada," Markle said Tuesday.

"We support any type of company or facility that encourages advancing our goal of trying to diversify our markets and increase market access."

Environmentalists hope to make Northern Gateway the next battleground against so-called "dirty" crude from the oilsands.

Last fall, a coalition of environmental groups was involved in a campaign in the U.S. that led to regulatory delays that have put TransCanada's Keystone XL pipeline to U.S. Gulf Coast refineries on hold.

Last month, opponents of Northern Gateway released their own commissioned report that questions the project's economics.

The report says there is enough existing pipeline capacity to handle up to twice the existing volume of bitumen exports by 2025. The group ForestEthics has said it plans to submit the report to the federal regulatory panel.