海角大神

At the edges of the Alaskan permafrost, a consortium of government and oil industry scientists are preparing to drill. They aim to tap one of the largest potential energy sources ever discovered, and one that few people have ever heard of: flammable ice crystals packed with hydrocarbons, called methane gas hydrates.

The project, a joint effort between BP, the United States Geo颅logi颅cal Survey (USGS), and the Department of Energy is set to begin in late 2009 or 2010 and marks the first large-scale production test of this unconventional substance. The group is nearing agreement on a drill site. [Editor's note: The original version called BP by its old name.]

Hydrates have been hailed as a paradigm shift in how to achieve energy independence and as a massively abundant source of cleaner-burning natural gas. Others fear it represents an environmental disaster in the making. Until recently it was thought too dangerous and too costly to extract to be of use.

That view is beginning to change. In a recently released report, the USGS for the first time announced details of large hydrate reserves in the Alaskan permafrost that should be recoverable using existing technology. The vast field could hold as much as 85 trillion cubic feet of gas 鈥� an amount far less than the dream scenarios put forward in the past, but still massive. Even more important, such movement makes the possibility of getting at the mother lode of hydrate resources 鈥� those located offshore 鈥� increasingly realistic.

鈥淚 never thought this would happen so quickly,鈥� says Carolyn Ruppel, a USGS research geophysicist who was heavily involved in prior hydrate research expeditions, referring to the planned production test. While the number of proposed drilling programs is small and significant obstacles remain, 鈥渢here has been a real change these past four years,鈥� Dr. Ruppel says. 鈥淚t鈥檚 partially from market pressures.鈥�

Underlying the interest in hydrates is their astonishing abundance 鈥� and the fact that they exist domestically in Alaska and the Gulf of Mexico. Their appeal is even greater for countries like Japan and India, which have strained oil or gas reserves but abundant hydrate deposits offshore.

A survey of hydrate estimates published in 2007 put US reserves at around 5,700 trillion cubic feet: 鈥淓ven this later figure ... is [about] 150 times the 95-percent-
confidence-level estimate of US conventional natural gas reserve,鈥� survey author Ruppel wrote, 鈥渁nd [about] 900 times the current annual gas consumption in the US.鈥�

Major hydrate research programs have cropped up in resource-constrained countries like South Korea, India, China, and 鈥� most notably 鈥� Japan, where Edie Allison of the Department of Energy estimates the government has sunk about $200 million into hydrate research. In 2007, Japan partnered with Canada to conduct a six-day production test in the permafrost to gain technical knowledge that could help fuel efforts to tap Japan鈥檚 vast undersea hydrate resources, perhaps the only major hydrocarbon reservoir that country has left.

The results were encouraging, but still an order of magnitude away from justifying large-scale commercial exploitation, says Gordon Pospisil, technology and resource manager for BP Exploration (Alaska) Inc., which is leading the 2009 Alaskan production test. Production would need to be 鈥渁bout a thousand times higher for this to be clearly economical.鈥�

Malcolm Lall, coordinator of the Indian National Hydrate Pro颅gram, says hydrate re颅颅sources off the Indian coast are too large to ignore. Hydrate potential there 鈥渋s sufficient for the energy needs of India for the next 15 years,鈥� he says. 鈥淲e鈥檙e taking this very seriously.鈥� More energy in颅颅de颅颅pendence is a huge in颅颅颅centive, he says, and India hopes to do production tests as early as 2013. 鈥淭he government has given this a lot of priority ... [to] get hydrates commercially viable,鈥� he says. 鈥淟et鈥檚 see who gets it first.鈥�

International and industry researchers will watch the progress of the BP/USGS test. It may, if things go well, turn gas hydrates from curiosity to solid energy policy. Because of the hydrates鈥� out-of-the-way locations, attractive production rates are necessary for industry and government to consider the vast, costly infrastructure of pipelines and cooling stations needed to get the stuff to market. 鈥淭he general consensus is that you can expect production problems similar to those of conventional resources,鈥� says Tim Collett, USGS鈥檚 lead hydrate research geologist.

Safety concerns also remain. Drilling turns solid hydrates into gas, but this process actually cools the gas, threatening to turn newly liberated gas bubbles back into solid hydrates in the middle of the drill itself 鈥� a dangerous prospect. Many also worry that drilling into hydrates might release clouds of gas that could start an underwater landslide. But most experts say that as knowledge of methane hydrates improves, drilling sites are moving away from high-risk areas.

Whether hydrates represent a key to domestic energy independence or an unnecessary risk is unclear. Hydrates represent a dramatic addition to natural gas resources, but natural gas, despite being cleaner than coal or oil, is still a fossil fuel that produces greenhouse gases. And raw methane, should it escape into the air, is more than 20 times as potent a greenhouse gas as CO2.

鈥淚f you still want to produce CO2, natural gas is much better than coal, but as a geoscientist I just get angry that you ever have to burn methane or coal,鈥� says Keith Kvenvolden, formerly of the USGS who has been studying hydrates for more than 30 years.

What are methane gas hydrates?

Trapped in ice crystals beneath the arctic permafrost and deep below the ocean is a volatile store of energy so vast that it could redefine world politics.

The mystery substance is methane gas hydrates, solid blocks of ice stuffed with methane gas molecules 鈥� natural gas. They are found all over the globe in such astoundingly large amounts that early estimates stated that there were more hydrates than all other fossil fuels combined. Better-informed estimates have tamped down those early figures, but hydrate reserves are still thought to be enormous.

Hydrates, which look like chunks of ice, were first brought to world attention in the mid-1960s by Russian scientists. Hydrates are compounds of water molecules that form under pressure and at low temperatures. They are like ice 鈥渃ages鈥� that trap gas molecules inside as they freeze. Hydrate water molecules are very accommodating: An ice cage consisting of a single molecule of frozen water can theoretically hold 160 gas molecules 鈥� meaning that finding just a small amount of hydrate can mean a lot of harvestable gas. And while hydrates can suck up a wide range of gases, the most common one is methane, clean-burning natural gas. Hydrates look like chunks of ice. You can even hold them in your hand 鈥� or light them on fire.

When the Soviets failed to find a way to exploit them, hydrates became little more than an academic curiosity for three decades. Barriers to exploration were large. The most abundant hydrates were thought to exist only in places forbidding to commercial exploration: in the arctic permafrost and scattered along continental margins under the sea.

No one knew how best to find them.

Rising oil prices, energy-security concerns, and better science has renewed interest in hydrates, which, it turns out, can be harvested much the way natural gas is, even though hydrates are solid.