The Associated Press reports that Denali, a joint effort of ConocoPhillips and BP PLC, formally proposed a $35 billion project Wednesday, with a pipeline stretching more than 1,700 miles and having delivery points to help meet gas needs in Alaska and Canada. Denali billed the project, which includes a gas treatment plant on the harsh North Slope, as "one of the largest private investments in the history of North America." Houston-based ConocoPhillips and Britain''s BP claim lease rights for about half of Alaska''s known North Slope gas. The Slope''s other major player, Irving, Texas-based Exxon Mobil Corp., is helping TransCanada Corp. of Calgary, Alberta, with a competing project that has been promised up to $500 million from the state. Its two options include a line to Canada with a comparable $32 billion to $41 billion price tag. Both ventures aim to be in service by around 2020, with plans to deliver about 4.5 billion cubic feet of gas per day to North American markets via larger lines to Canada. TransCanada''s other option is smaller in size and cost -- between $20 billion and $26 billion -- for a liquefied natural gas facility that would export the fuel by ship.