|A test-well for collecting gas hydrates in Mallik, Canada. (Photo: USGS)|
Remember when shale gas was the next big thing? The game changer that would revolutionize the energy world, providing Americans with an abundant source of clean, environmentally friendly fuel?
Shale gas, undoubtedly, has turned out to be a big thing. Natural gas production has been steadily climbing since 2006, and natural gas prices are so low that gas is displacing dirty coal as the fuel of choice in our power plants.
But, with concerns over water pollution and air pollution from the process of horizontal drilling and hydraulic fracturing (fracking) -- and global warming impacts (conceivably as bad as or even worse than coal) from natural gas leakages from the extraction and piping of the fuel -- the bona fides of shale gas as an environmentally friendly fuel has been pretty well tarnished.
Now a new source of natural gas threatens to take shale's position as the ultimate energy game changer of our times: methane hydrates.
Methane Hydrates: A Veritable Gold Mine?
A methane hydrate is an ice-like cage of water molecules in which a molecule of methane is trapped. Methane hydrates form at low temperatures and high pressures like those found below water depths of about 500 meters off the coasts of continents, in seafloor sediments and in permafrost. (More here, here and here.)
And here's the thing. Geologists estimate that there are enormous quantities of methane stored in the ocean bottom as hydrates. How much is enormous? Would about twice the amount of carbon that is found in all the other fossil fuels meet the enormous criteria? (See here, here and here.)
But having a huge resource of methane sitting on the ocean floor is one thing; being able to extract the stuff economically and bring it to the surface is another. Just look how long it took for the commercial shale gas boom to develop. Decades from the time the first well was fracked.
And as the Deepwater Horizon blowout and its ongoing ripple effects highlight, moving into new areas of energy extraction is no easy task and could be fraught with accidents waiting to happen. (An interesting aside: methane hydrates compounded the tricky business of trying to seal the Deepwater Horizon leak.)
So economics, technology and scientists' relatively poor understanding of methane hydrates have seemingly conspired to keep the natural gas locked in these hydrates at bay ... until just about now.
Move Over, Shale. Methane Hydrates' Turn?
|Water molecules (1 red oxygen and 2 white hydrogens) form a pentagonal dodecahedron around a methane molecule (1 gray carbon and 4 green hydrogens). This represents 2 of the 8 parts of the typical Structure I gas hydrate molecule. (Courtesy: USGS)|
On Tuesday Japan announce that a Japanese teamd, as reported in the New York Times, had successfully "drilled into and then lowered the pressure in the undersea methane hydrate reserve, causing the methane and ice to separate [and] ... then piped the natural gas to the surface." It was quite a feat. The extraction came from a formation that was not only about 1,000 meters below the sea surface but also 300 meters below the sea floor.
The Japanese view the methane hydrate deposits in the Pacific Ocean and the Sea of Japan as the potential answer to their energy woes. An energy-poor country that is only "16 percent energy self-sufficient," [pdf] Japan saw its energy challenges skyrocket when it had to pull the plug on nuclear power following the Fukushima disaster. And so now they've tapped a potential fix. Could other countries be far behind?
In fact, last year the United States, using a different technology that incorporated the injection of carbon dioxide, successfully "extract[ed] a steady flow of natural gas from methane hydrates" on the Alaska North Slope. The 30-day flow of natural gas was "five times longer than the previous record of six days set at a different well in 2008."
Following that successful trial run, the U.S. Energy Department announced "14 new research projects across 11 states that will be a part of an expanding portfolio of projects designed to increase our understanding of methane hydrates' potential as a future energy supply."
|Gas hydrate recovered in shallow layers just below the seafloor during piston coring in the Gulf of Mexico. (Photo: USGS)|
A New Resource Tapped, New Questions Raised
But while gas companies and investors might salivate at the thought of all that carbon-rich stuff sitting at the bottom of the ocean just waiting to be extracted -- and many energy-hungry consumers might applaud the prospect of another abundance source of cheap fuel (see here and here) -- others are less sanguine about the prospect of tapping what the U.S. DOE calls "a vast, entirely untapped resource that holds enormous potential for U.S. economic and energy security."
|Scanning electron microscope image of gas hydrate (Photo: Courtesy of L. Stern, USGS Gas Hydrates Project)|
First and foremost, methane is a hydrocarbon. It may be cleaner than coal and petroleum, but it still adds carbon dioxide to the atmosphere when it is burned. If we are serious about climate change, we are going to have to wean ourselves off of all hydrocarbon fuels no matter how plentiful and cheap.
And methane, you will remember, is a greenhouse gas and a potent one at that -- about 20 times the global warming potential of carbon dioxide (using a 100-year time frame). If something (for example ocean warming) caused the hydrates to become unstable, allowing the methane to vent to the atmosphere, the climate impact would be devastating. That's why destabilization of methane hydrates is usually included in the list of scenarios that could lead to rapid, catastrophic climate change -- right up there with the melting of the Arctic permafrost.
How likely are the methane hydrates to become unstable in our globally warming world? Not likely. While global warming is causing ocean temperatures to rise, the best estimates are that the rise will not be sufficient to destabilize the hydrate deposits. Whew.
But here's the question that should, in a perfect world, give us all pause. Will the process of extracting methane from hydrates destabilize these deposits causing the methane to bubble up into the atmosphere before the gas companies can pump it out? Will this new energy game changer from methane hydrates actually prove to be a climate game destroyer? I don't know about you, but I would hate to find out the hard way.
Learn More About Gas Hydrates