The Alaska Pipeline Project, a joint effort between TransCanada Corp. and Exxon Mobil Corp., announced Thursday that it will begin its natural gas pipeline open season on Friday.

An open season is when a company that wants to build a pipeline lays out the details of its plans, such as how much it will charge to move the gas. In response, shippers make bids reserving space in the line by promising a long-term financial commitment to the project.

But that isn't the only open season oil-crazed Alaskans will have to cheer on this year. The Denali Project, a joint effort between BP and ConocoPhillips, is planning to start its open season on July 6.

The results of the dueling plans and the bids they receive will shed a lot of light on that eternal Alaska question: Will this state ever see a gas pipeline? It's taken as a northern no-brainer that only one of the lines will be built. (Cheat sheet: the TransCanada and ExxonMobil line is the one that scored $500 million in state subsidies under the Alaska Gasline Inducement Act.)

The Alaska Pipeline Project's open season, which will last 90 days, will have two options for gas shippers to bid on. The first is a line running from the North Slope down to Alberta, Canada. That line would be about 1,700 miles long, and would serve the North American market. The other option is a line that would run from the North Slope to Valdez, a distance of about 800 miles. In that option, the gas would be liquefied and shipped to both North American and international markets.

The  press release put out by TransCanada and Exxon Mobil said only one of its two project options will advance, and they figure the open season results will determine which option.

The release also included more details about the proposed lines, and a breakdown of the open season process.

Contact Joshua Saul at jsaul(at)alaskadispatch.com.