Denali rolled out specifics on its plan to build a pipeline from Alaska's North Slope south to North American markets today, saying an open season could start July 6 and run through early October.

The Federal Energy Regulatory Commission will have to approve the open season plans first.

Citing $140 million and 600,000 hours of work Denali -- a partnership of BP and ConocoPhillips -- has put into the pipeline plans, partnership president Bud Fackrell also did not shy away from pointing out signifciant challenges. Among those are market factors outside Alaska, including shale gas and LNG exports, plus construction factors. Can the biggest infrastructure project in the U.S. come in on time and on cost?

Other risks have to do with things outside Denali's control. Fackrell noted that the Slope's three big producers, Exxon, BP and Conoco, have long held that they need long-term tax certainty from Alaska in order to make the 20-plus year commitment to a pipeline, and that other tax matters will have to be settled. Fackrell also questioned the ability of those producers to commit gas from the rich Pt. Thomson field -- with an estimated 8 trillion cubic feet of gas and 200 million barrels of condensate -- into a line. That's because the Pt. Thomson field is the subject of ongoing litigation with the state, outcome unknown.

Fackrell said the open season is designed to see whether producers believe the reward of market price is worth the risks associated in developing North Slope gas.

"We know that the North American market is very volatile right now," he said. "The open season will help us understand if they're willing to commit gas resources into that market, or not ... No one is waiting for Alaska gas."

Larry Persily, the new federal coordinator for Alaska natural gas projects, greeted today's open season filing with some optimism. Mostly, that centered around a similar price tag and tariff for the second project. Two projects with prices in the same ballpark should give confidence to producers, he said.

Denali's cost, pegged at $35 billion, is within the range set out by TransCanada and Exxon Mobil's rival Alaska Pipeline Project, with a pledge of up to $500 million in state help and a license under the Alaska Gasline Inducement Act.

AGIA holds a host of state conditions that the TransCanada project is bound to deliver on, and that the producers with gas to commit to a line have said simply won't work for them.

Denali doesn't face the same state must-haves. One of the top among those is a requirement that the initial shippers pay part of the bill for expansion later on if other producers want in.

But companies bidding on space in Denali's line also won't have a couple of perks that come with AGIA. For one thing, companies that bid gas in an initial open season have a chance at locking down the state's current tax rate for the first 10 years of pipeline flow.

Like TransCanada's project, the Denali offer includes offtakes for gas delivered within Alaska and through Canada. While Denali isn't putting out a second possibility -- a smaller line straight south to Valdez for LNG exports -- Fackrell said that lacking bids on 85 percent of capacity in this initial open season, there's room for recrafting a smaller line or considering a line for LNG export, instead of through Canada.

Contact Rena Delbridge at rena(at)alaskadispatch.com.