Frozen shore line

The lesser known hydrocarbon (Day 55)

Frozen shore lineWalk up to any typical man or woman in the street and ask them where their energy comes from to power their homes, cook their food, keep the cold out and fuel their cars and you’ll probably get a very long list of answers.

If you posed the question, what power source has more energy in it than all the world’s oil, coal and gas put together, only a few are likely to get the right answer.

In fact the answer is gas hydrates – the lesser known hydrocarbon. Otherwise known as fire ice and more loosely termed methane hydrate, the gas presents as ice crystals with natural methane gas (and other gases) locked inside.

They are formed through a combination of low temperatures and high pressure, and are found primarily on the edge of continental shelves where the seabed drops sharply away into the deep ocean floor.

It is estimated that one cubic metre of the compound releases about 160 cubic metres of gas, making it a highly energy-intensive fuel. And there’s lots of it – as much as 20 trillion tons of methane under the sea.

At the moment, gas hydrates appear to be on the back-burner, but that doesn’t mean chemical engineers aren’t looking at their potential and where to find them.

Rice University's George Hirasaki left, and Sayantan Chatterjee
Rice University chemical engineer George Hirasaki, left, and alumnus Sayantan Chatterjee. Photo credit: Rice University.

At Rice University in the US, chemical engineer George Hirasaki and alumnus Sayantan Chatterjee have led a project to build a two-dimensional mathematical model to help identify rich pockets of gas hydrate under the ocean floor.

Their model extrapolates data from several sources: one-dimensional core samples, seismic surveys that image the fractures as well as stratified layers of sand and clay that build up over millennia, and the geochemistry of sediment and water near the ocean floor, which offers chemical clues to what lies beneath.

The research behind their model was presented by Chatterjee at the seventh International Conference on Gas Hydrates in Edinburgh, Scotland. His achievements include first prize at the Society of Petroleum Engineers’ Young Professionals meeting and second prize at the Gulf Coast Regional student paper competition.

But like all hydrocarbons, it’s not good news for climate change. And even if not exploited as an energy source, current global warming effects could cause the the hydrate to melt releasing the methane into the atmosphere.

It’s a story that will unfold over the next few decades and it will be an interesting one to watch, especially if political considerations such as energy independence and security bring gas hydrates increasingly to the attention of governments.

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