Story link:



  Gas hydrates: a gift wrapped in problems

This piece of good news comes with some caveats. So [t]read with caution.

Buried deep along India’s 7,500 km of coastline is a vast fuel reserve that can meet our needs for several centuries. Global reserves of gas hydrates—the ‘fuel’ under reference´┐Ż are estimated to be “twice the known oil and gas reserves of the world.” That quote is from Mr Harsh K Gupta, Secretary to Indian government’s Department of Ocean Development. He was addressing the media in Jan, 2004 during a seminar in Chennai on “New frontiers in marine bioscience research”.

Gupta was referring to hydrates of methane. Well, what are they? They are part of a chemical formation called gas hydrates in which a core of methane is trapped in a cage of water molecules. They are ice like crystals that lie deep in the oceans, at very high pressures and very low temperatures found at ocean depths greater than 500 metres. Source of this methane is biogenic; from the organic detritus that descend to the ocean floor where bacteria act on them to generate methane.

The interesting thing is about these hydrates is that at great pressures and low temperatures in the oceans, they are very stable crystals. If mined and brought to atmospheric conditions they produce 160 times their volume of methane. And that is what is seducing energy hunters. Methane is a readily usable fuel.

Now to the caveats. What are they? First, the technology to mine these hydrates is at its infancy. It may need about twenty years of patient, sensitive development before we have a mature extraction technology. India has entered into an agreement with Russia and some exploratory work has begun.

Next—and, more seriously— there are two facts that can combine to cause major disasters. Fact-Set-One: there is 3000 times more methane down there than there is now in the atmosphere; methane is 10 times worse than carbon dioxide as a climate warmer. Fact-Set-Two: methane hydrate sediments are close to coastlines; they can be in layers that are 13 kilometres deep; mining for them can set off ‘landslides’ down there.

The real hazard is when we combine the two sets. Mindless mining can cause landslides, release bursts of methane into the atmosphere and accelerate global warming, with consequences that are well known. All this is because, gas hydrates where they are, are stable; but once dislodged can be—due to their great expansion ratio—very volatile.

What we are looking at is a potential that we can’t jump at and grab, but must winkle out with great care.

For those with greater interest in this subject that will be heard more frequently in India in the coming years, here are links to pursue the subject further. For an easy introduction to the subject go to this US Geological Survey page. A slightly more technical page is here. A racy chat on the subject can be found here. Finally, India’s National Institute of Oceanography page on the subject.

As cited