* Line to Alberta to cost $32 bln to $41 bln
* All-Alaska route to cost $20 bln to $26 bln
* Files open season plans with FERC (Adds Alaska reaction. In U.S. dollars unless noted)
By Scott Haggett and Yereth Rosen
CALGARY/ANCHORAGE, Jan 29 (Reuters) - TransCanada Corp
The companies said the cost of the 1,700 mile (2,700 km) pipeline carrying at least 4.5 billion cubic feet of gas daily from Alaska's North Slope to Alberta will range between $32 billion and $41 billion, up from a previous $26 billion forecast.
The line, mulled for more than a generation, would be among the largest and most expensive civil engineering projects ever undertaken in North America, requiring years of planning and construction and massive financing.
"No matter how you measure it, the Alaska Pipeline Project would be an exceptional world leading project and one of the largest private investments in the history of North America," Paul Pike, Exxon Mobil's senior project manager for the line, said on a conference call.
For Alaska, which depends on oil for nearly all its state operating revenues, a natural gas pipeline is seen as economically crucial. North Slope oil production has dwindled to a third of the 2 million-barrel-a-day peak reached in 1988, and continues to decline.
Some political leaders hailed Friday's announcement as a big step toward reaching the gas pipeline goal.
"Bringing Alaska's gas to market presents a tremendous economic opportunity for the state," Alaska Governor Sean Parnell said in a statement. "Alaskans have waited 30 years to advance this project, and today's news marks a significant milestone in achieving this opportunity."
A smaller line, running from the gas fields of the North Slope to a separately built liquefied natural gas facility near Valdez, Alaska, would cost between $20 billion and $26 billion and could be built instead of the larger project if shippers chose the option.
OPEN SEASON PLANNED
The new estimate for the lines, which could be in service by 2020, came as the partners filed plans with the U.S. Federal Energy Regulatory Commission (FERC) to hold an open season to attract potential shippers.
"This open season will test potential customers' interest in utilizing the Alaska Pipeline Project to transport their natural gas to market," said Tony Palmer, TransCanada's vice-president of Alaska development.
Calgary-based TransCanada is the state of Alaska's preferred pipeline sponsor and holder of a state license under the Alaska Gasline Inducement Act (AGIA).
It added U.S. energy major Exxon Mobil, one of the three
major North Slope natural gas producers, as a partner to its
proposal last year. The other two producers, BP Plc
However the two partners expect that they've squeezed the cost for shippers down, making their proposal attractive. They plan to a 20 percent capital risk in the project, reducing the costs needed to be covered by customers by between $6 billion and $8 billion.
As well, they've cut their planned return on equity to 12 percent instead of the 14 percent return TransCanada had forecast in its AGIA filing.
Including those cuts and other smaller factors, the partners expect shippers who commit during the open season will pay $500 million less per year on tolls than forecast in the AGIA application.
"Assuming that FERC approves our plan as filed, and ... the customers commit their gas in that initial open season, they will see lower tariffs," Palmer said. "They will see lower tolls to their account on the order of $500 million per year."
Still, the rival Denali project, backed by BP and Conoco, is going ahead as planned, with its own open season scheduled to launch in April.
"I am confident that we will have an attractive commercial offer for our potential customers," said Bud Fackrell, Denali's president. "Today's announcement by TransCanada and Exxon doesn't change anything for us. We're on track."
TransCanada has offered BP and Conoco an equity stake in its project, saying the support of all three producers, as well as the state, is needed before its project proceeds. However negotiations with the rival producers have yet to take place .
TransCanada and Exxon filed plans for the open season with FERC, which has 90 days to approve the proposal. A separate open season will be staged for the Canadian portion of the line.
TransCanada shares fell 11 Canadian cents to C$34.17 on the Toronto Stock Exchange while Exxon dropped 53 cents to $64.43 in New York.
($1=$1.07 Canadian) (Editing by Jeffrey Hodgson and Rob Wilson)