Big natural-gas find in Alaska

WASHINGTON — Federal scientists have concluded Alaska's North Slope holds one of the nation's largest deposits of recoverable natural gas in the form of gas hydrates, a finding that could open a major new front in domestic energy exploration.

Researchers have speculated for years that gas hydrates — a combination of gas and water locked in an ice-like solid that forms under high pressure and low temperatures — could be an important source of natural gas in the U.S. and worldwide.

Today, the U.S. Geological Survey (USGS) will release a study estimating 85.4 trillion cubic feet of natural gas can be extracted from Alaska's gas hydrates, an amount that could heat more than 100 million homes for more than a decade.

Brenda Pierce, manager of the agency's energy-resources program, called the find "groundbreaking" and said: "I don't want people to think our problems are solved, but this has real potential."

Part of the reserve's significance, federal officials said, is that gas companies can use existing technology to tap into it.

A coalition of U.S. and international experts conducted three tests on gas hydrates over the past five years in the United States and Canada and demonstrated that gas can be extracted by reducing the pressure that binds them together.

Gas hydrates also have been found in the Wyoming basin, Texas's western Gulf basin, and the San Juan basin in New Mexico and Colorado, as well as in several offshore areas.

"The assessment points to a truly significant potential for natural-gas hydrates to contribute to the energy mix of the United States and the world," said Interior Secretary Dirk Kempthorne. "This study also brings us closer to realizing the potential of this clean-burning natural-gas resource."

The prospect of extracting methane from gas hydrates, some of which lie below the permafrost of the Arctic National Wildlife Refuge, worries some environmentalists.

Athan Manuel, of the Sierra Club, said the refuge should stay "inviolate" and that tapping into gas hydrates can also harm less-pristine areas.

"The process is still pretty damaging to ecosystems," Manuel said, noting that companies must inject water into the reservoirs in the same way they extract methane from coal beds in the West. "Bottom line, this is a very destructive way to extract natural gas."

Pierce said the government will examine the potential environmental effects as "the next step" in its analysis. "Like every resource, it's going to have impacts," she said.

USGS Director Mark Myers said the process is likely to be less damaging than coal-bed methane extraction because water is more plentiful on the North Slope and fewer wells will be needed.

Even if industry manages to extract the gas, it will be years before companies can send it to the lower 48 states.