FAIRBANKS — State officials said Tuesday night that efforts to spur construction of a massive natural gas pipeline are on schedule despite skepticism from critics and some lawmakers.

The plan, pitched by former Gov. Sarah Palin under the Alaska Gasline Inducement Act, is projected to have drawn

$150 million in investments from the team of TransCanada and Exxon Mobil by mid-summer, according to an October progress report.

State commissioners and a federal coordinator said in Fairbanks that the spending is one sign their effort is working. Speaking at West Valley High School, the group said TransCanada should be confident as it seeks participation from potential gas suppliers this spring for a pipeline that would connect Alaska’s vast North Slope gas fields to markets.

Revenue Commissioner Pat Galvin noted the act’s basic goal was to spark momentum toward construction of such a line.

“We’ve achieved that in spades,” he said, adding that a competing project, dubbed Denali, also has moved ahead under BP and ConocoPhillips.

TransCanada and Exxon are working under exclusive, state-offered development incentives included in the 2007 act. BP and ConocoPhillips are working without those incentives.

Opinion among state lawmakers and industry watchers remains divided about whether competing projects can connect natural gas — beyond small, existing export projects — to the international marketplace. Former Gov. Frank Murkowski, a vocal critic of AGIA, continued to push Tuesday for critical debate regarding the state’s energy policies.

Murkowski told Fairbanks university students, faculty and visitors that a decision by Palin, his successor as governor, to spark competition between potential pipeline builders has left the state with a divided front. He said that result, coupled with energy companies’ discoveries of natural gas reserves within shale deposits in other U.S. states, compounds coming revenue troubles as oil production here dwindles.

Murkowski said state leaders must rework tax frameworks to spark investment in oil and gas production and to convince energy companies to commit gas holdings to a future pipeline.

“Those are fundamental prerequisites associated with the economic certainty of a gas line,” Murkowski said. He called TransCanada “a great company” but repeated his concern that it lacks control over gas leases, control the three energy companies hold.

State officials suggest such concerns are misplaced. Tom Irwin, the state’s resources commissioner, said even with recent technological improvements, shale-trapped gas in other states can’t meet the country’s long-term demand.

“Our gas competes” with other domestic reserves, Irwin said.

A progress report on AGIA, released to lawmakers on Halloween, said despite short-term volatility, long-term forecasted natural gas prices and long-range North American energy demand projections have shown “little impact” from the global economic roller-coaster. It acknowledges shale gas development, aided by better production technology, has grown but points to other signs, including the fact that the privately led Denali project is in the works, as indication the market for Alaska’s gas is alive.

Contact staff writer Christopher Eshleman at 459-7582.