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Imagine a fossil fuel that’s not only carbon neutral – it’s carbon negative. Research being done right now on a form of natural gas called methane hydrates could change our energy future forever.

Methane hydrates are locked away in ice crystals buried deep below the ocean floor and in the Acrtic permafrost. Researchers believe these hydrates contain more energy than the entire world’s coal, oil and conventional natural gas combined.

The hydrates form when methane gas comes into contact with water at low temperatures and high pressures. On the website newscientist.com one writer says, “to the naked eye, the hydrate looks like regular ice. However, while it is made up partly of water, the water molecules are organized into ‘cages’, which trap individual molecules of methane inside them.

So, why haven’t we gone after them already? Well, it seems the compounds are extremely unstable when they undergo changes in temperature and pressure. Just drilling into them like we do to get oil and natural gas now would cause pressure changes and the hydrates would simply decompose. During the decomposition, cooling occurs. That cooling causes more hydrates – or ice crystal “cages” - to form. So, the natural gas just gets locked up again and can’t be extracted. So, scientists have struggled with finding the technology that can unlock these resource beds safely, efficiently and economically.

They’ve struggled, that is, until now. A New York Times story earlier this month reported on research out of Columbia University. A research team lead by chemical engineer Marco Castaldi tested a fuel-burning heat source that provides a steady stream of heat to decompose the hydrates and release the natural gas without the same hydrate reforming. Castaldi says, because of the steady heat flow, this combustion method allows them to extract the natural gas. Two by products of the combustion are water and carbon dioxide. As those byproducts cool, they form their own hydrate – a carbon dioxide hydrate. And, by a miracle of science itself, the natural gas extraction method all of a sudden became “green”.

"That's exactly the direction you want," Castaldi said. "As things cool down, carbon dioxide forms a hydrate, so it gets sequestered." Locked away, frozen in ice, rather than released into the atmosphere.

He said scientists are still conducting research, but preliminary tests show the method can sequester at least as much carbon as produced in the combustion process.

"It's at least carbon neutral," he said, "but there are indications it could be carbon negative.”

Other researchers agree.  They are calling this “ice that burns” a truly green fossil fuel. We already know that the natural gas we are using now is the cleanest burning of all the fossil fuels. We know that it is the bridge fuel to our future energy. However, as scientists continue their research on these gas hydrates, they insist they are closer to unlocking these resources than America is to fueling its energy needs solely by wind or solar power.

"These gas hydrates could serve as a bridge to our energy future until cleaner fuel sources, such as hydrogen and solar energy, are more fully realized," says study co-leader Tim Collett, Ph.D., a research geologist with the U.S. Geological Survey (USGS) in Denver, Colo.

The USGS team is testing another method of extraction. Their research works more on a “replacement” strategy. According to newscientist.com, the hydrate “cages” prefer to have carbon dioxide at their cores. So, if carbon dioxide is pumped into the hydrate, it spontaneously takes the methane’s place. Researchers believe they should be able to simultaneously extract methane and store carbon dioxide.

So far, all of these research methods have only been tested in the lab, but all indications show they should work in the field as well. The U.S. Department of Energy is working with ConocoPhillips to begin a field trial in Alaska.

The USGS researchers estimate that 85.4 trillion cubic feet of natural gas could potentially be extracted from gas hydrates in Alaska's North Slope region, enough to heat more than 100 million average homes for more than a decade.

When you add that to the known reserves we have in our shale plays in places like the Woodford Shale here in Oklahoma, it proves natural gas will be a viable energy source for our future for many decades to come.

Resources:
Science Daily
New Scientist


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These gas hydrates could serve as a bridge to our energy future until cleaner fuel sources, such as hydrogen and solar energy, are more fully realized.