TransCanada Corp. on Friday filed with regulators hundreds of pages of new information describing how it plans to obtain commitments for natural gas to fill its proposed multibillion-dollar North Slope pipeline.

The new documents show that building the pipeline could be nearly twice as expensive as TransCanada, a Canadian pipeline company, predicted three years ago. However, the new estimates -- ranging from $26 billion to $41 billion -- are within the range that has been used by state officials for the project, which many see as critical to Alaska's future economy.

The documents also reveal that the company is trying to sweeten the deal for potential shippers -- including oil producers BP, Conoco Phillips and Exxon Mobil. TransCanada says it is reducing the amount it will charge to ship the gas by $500 million per year for 25 years, or $12.5 billion. That's possibly good news for people in Alaska: lower shipping costs translate to higher royalties and tax revenue for the state and larger profits for the producers.

Despite the monumental risks of building the long-sought pipeline -- including its huge expense and new competition from shale gas producers in the Lower 48 -- TransCanada officials said Friday their project remains competitive and gas can begin flowing by 2020.

TransCanada touted its Friday actions as historic: It's the first time a company has filed detailed plans seeking federal permission to hold what is called an "open season" and seek gas commitments for the North Slope pipeline.

But TransCanada has a big competitor: In April, Denali, the pipeline company created by BP and Conoco Phillips, also plans to file the documents required to hold an open season. Both companies' plans must be approved by the Federal Energy Regulatory Commission. TransCanada's open season is expected to begin in May and end in July. Denali's would begin around July and run for 90 days.

Not unlike TransCanada, the North Slope oil producers have stayed cautiously optimistic about the gas line.

"We want to find a way to move (the gas). It really matters," said Steve Rinehart, BP's spokesman in Alaska.

He said his company will carefully review the TransCanada and Denali proposals during the two open seasons.

THE DETAILS

TransCanada's filing on Friday includes revised construction cost estimates and proposed shipping costs for two major pipeline alternatives: delivering the North Slope gas to a pipeline hub in Alberta, Canada; and piping it to a liquefied natural-gas terminal in Valdez from which the gas could be shipped to Asia or the Lower 48.

TransCanada said it is possible to build one but not both, given the capacity required to operate the pipelines and the amount of gas known to exist on the Slope. Either project could start delivering gas by 2020 and be fully in service by 2021, the company said.

TransCanada estimated the cost of building the Alberta project at $32 billion to $41 billion and the Valdez LNG project at $20 billion to $26 billion. The LNG cost estimate does not include the cost of building tankers or a liquefaction plant in Valdez, which could add billions. TransCanada says it does not plan to be involved in those aspects of a Valdez project.

On Friday, TransCanada vice president Tony Palmer defended the steep climb in the estimated cost of the Alberta pipeline proposal, estimated at $26 billion in 2007. Since then, the cost of building oil and gas projects worldwide has ballooned, the U.S. dollar has weakened and TransCanada has learned from its partner Exxon Mobil that building a massive industrial plant near the Prudhoe oil field to treat the gas would be costlier than thought, Palmer said.

TransCanada is pursing the North Slope pipeline project with Irving, Texas-based Exxon, the largest single holder of gas leases on the Slope. The pipeline project's senior manager, Paul Pike, works for Exxon.

TransCanada holds a state license granted by the former Palin administration to develop the project, entitling it and Exxon to receive up to $500 million in incentives from the state government for their spending to advance the project.

REACTIONS

Gov. Sean Parnell, the Alaska congressional delegation and several state legislators said Friday morning they are pleased that the pipeline project is progressing.

"This marks the first time Alaska has seen a major producer come together with a pipeline company to solicit binding commitments for the transport and delivery of North Slope natural gas to markets in the Lower 48," said Sen. Lisa Murkowski, R-Alaska.

TransCanada's competitor, Denali, said its project remains on track.

"I'm am confident that we will have an attractive commercial offer for our potential customers," said Denali's president Bud Fackrell, in an e-mailed statement.

But he also warned that the potential shippers may balk over the increased gas supply in the Lower 48, the state's taxation and other project risks.

A few current and former state legislators and at least one Wall Street analyst said they are also worried over the pipeline's prospects.

Sen. Lesil McGuire, who co-chairs the state Senate Resources Committee, said she is worried about the TransCanada project's reliance on federal loan guarantees, which still haven't been fully approved, and about the likelihood that North Slope's producers will not commit their gas without revisions to the state's tax law.

Republican gubernatorial candidate Ralph Samuels, a former state representative, said he doesn't believe the state's process for developing a pipeline will produce anything but delays. He was the only one of 60 legislators to vote against the Alaska Gas Inducement Act, a Palin administration-backed law that ultimately led the state to award a pipeline license to TransCanada.

Wall Street oil and gas analyst Fadel Gheit said he doesn't think that investors will support building a $30 billion to $40 billion pipeline given the massive amount of gas coming available in the Lower 48. That is, not unless the government makes gas "the mandatory fuel of choice," he said.

For that reason, he sees the LNG project, which could export gas overseas, as more attractive. Plus, it's cheaper and faster to build, said Gheit, of Oppenheimer & Co., a New York investment firm.

State officials and the pipeline companies say it will be up to the gas shippers to decide whether they prefer a Valdez or Alberta pipeline. But the state's deputy division director for oil and gas said the fears of competition from Lower 48 gas is overblown.

As regulators require less-polluting fuels, "the demand for gas is going to grow aggressively," said Kurt Gibson, deputy director for the Alaska Department of Natural Resource's oil and gas division.

Find Elizabeth Bluemink online at adn.com/contact/ebluemink or call 257-4317.