Anchorage Daily News

WASHINGTON -- Frozen crystals packed with concentrated natural gas and buried 2,000 feet below the permafrost on Alaska's North Slope could become the next major domestic energy source, an assessment released Wednesday by the U.S. Geological Survey found.

The USGS study shows that in the North Slope, those frozen methane-and-water crystals, known as hydrates, contain as much as 85.4 trillion cubic feet of recoverable natural gas. That's enough to heat 100 million homes for as much as 10 years, said Interior Secretary Dirk Kempthorne.

New research into how to extract those resources has moved the possibility of recovering natural gas hydrates from the realm of "science and speculation" to that of the "actual and useful," Kempthorne said Wednesday.

Globally, "hydrates have more potential for energy than all other fossil fuels combined," Kempthorne said. "This can be a paradigm shift."

Government research is beginning to show that it may be possible to extract hydrates using depressurization, a technique used to get at more conventional fuel sources. Simply boring into the ground may be enough to change the pressure to extract it, said Steve Rinehart, a spokesman for BP Alaska. Or the pressure could be changed with some sort of pump.

Gas hydrates exist all over the world, including offshore, but a combination of cold and pressure makes them especially prevalent in the Arctic, where there's also an existing oil-and-gas infrastructure to study them. They're described by the Department of Energy as "ice-like solids that results from the trapping of methane molecules within a lattice-like cage of water molecules." Hydrates release gaseous methane -- the main component of natural gas -- when they melt.

Kempthorne on Wednesday demonstrated the flammability of the substance with laboratory-created hydrate made by government researchers. Real hydrates, which are 164 times more concentrated than natural gas, would be far too valuable to burn in part because core samples are so rare.

Kempthorne lit a match to a fist-sized lab sample, sending up a small flare. He also passed out small, pebble-sized samples to reporters attending his press conference. When Kempthorne dropped a chunk of hydrate into a glass of water, it fizzed like Alka-Seltzer. As the human hand warms it, the hydrate snaps and crackles, releasing gas and water vapor.

SKEPTICISM

Two of the biggest North Slope producers, Conoco Phillips and BP, have been involved in some of the government studies. Conoco has largely been researching whether it's possible to inject carbon dioxide into wells to replace the hydrates. That also would allow the carbon dioxide, a greenhouse gas, to be sequestered in the wells.

BP last year participated in government studies that drilled for core samples of hydrates. So far, there have been no actual tests of producing hydrates as commercially viable natural gas. That's next, but BP and Conoco both remain skeptical. There are tremendous conventional natural gas deposits in Alaska to consider first, Rinehart said.

"We see the potential," he said, "but our outlook is conservative at this point, because there really has not been a long-term production test."

There's room for "healthy skepticism" on the environmental front, too, said Mike Daulton, the legislative director of the National Audubon Society. The extraction could threaten the stability of the permafrost in Arctic Alaska, Daulton said, and there also are concerns that in the process of extracting a relatively clean-burning fuel there's a risk of releasing vast amounts of methane.

"There's a lot that still needs to be proven with regards to the safety," Daulton said. "There's the potential for the release of methane, which is much more potent than carbon dioxide as a greenhouse gas."

GULF OF MEXICO FIRST?

Although there are tremendous hydrate deposits in Arctic regions, they also exist in the deepwater regions of the Gulf of Mexico, a region where there are natural gas pipelines, unlike on Alaska's North Slope. Even though much of the government research into hydrates has taken place in Alaska, it might be that it is cheaper to consider the Gulf first.

Other countries that import most of their energy -- including Japan and India -- have been aggressively pursuing their own hydrate potential.

But the possibility of recovering natural gas hydrates in Alaska also could add to the usefulness and potential life span of a possible multibillion-dollar natural gas pipeline under study. The pipeline would send more conventional sources of natural gas from the North Slope to markets in the Lower 48 or Canada.

It could be part of a "balanced national energy plan in the years ahead," said Sen. Lisa Murkowski, R-Alaska, calling it "great news for not only Alaska's future economy, but also for the nation."

There's an estimated 35 trillion cubic feet of proven natural gas reserves in the North Slope of Alaska, said Mark Myers, director of the USGS. Another several hundred trillion feet of conventional natural gas is also potentially available but less accessible. The possibility of extracting keeping the proposed pipeline filled for a longer period of time with natural gas hydrates only "leads to more confidence to invest in the pipeline," Myers said.

"They were already going to build it, but it does help bolster the case," said Sara Banaszak, a senior economist with the American Petroleum Institute. "The more gas you can help transport with the pipeline, the more economic the project is."

Find Erika Bolstad online at adn.com/contact/ebolstad or call her in Washington, D.C., at 202-383-6104.