Perhaps the term gas hydrate is an unfamiliar one. Perhaps it has been hushed in the media to avoid pandemonium and chaos. Maybe the media were right, but then again, they could have been wrong.
Gas hydrates are a tremendous resource of carbon deposits containing methane, propane, or carbon dioxide. These deposits lay beneath the permafrost layer in the far North and beneath ocean floors around the world. Gas hydrates are usually trapped in an ice-like cage often referred to as a lattice structure. While still definitely an estimate, scientists have projected approximately 100,000 trillion cubic feet (TCF) of methane in resource-grade deposits. That is considerably more than the approximately 6,600 TCF of global natural gas reserves and 100 times the annual global gas consumption, according to a 2011 U.S. Geological Survey paper.
The gas hydrates we will focus on are methane hydrates which “are a little like conventional oil and gas; they come from organic material in the muds and sands beneath the sea floor. The difference is that they are low temperature,” said Ray Hyndman, Professor in the School of Earth an Ocean Sciences of the University of Victoria British Columbia, Canada, in an interview on Planet Earth - Our Loving Home.
The deposits are commonly found on continental slopes around the world and under permafrost in the far north. Some of these deposits are very near the seabed surface, making them accessible, while others offer production and access challenges. Several research projects like the Canadian Mallik Project are looking at the feasibility of harvesting the gas hydrate deposits.
One particular deposit along the Alaskan North Slope houses approximately 85 TCF of recoverable methane from gas hydrates. “While this represents three and a half times the U.S. current use, there is no pipeline at present from there to the rest of the U.S., so any gas produced there would be used for local power generation or for re-injection into the oil reserves to maintain pressure and enhance oil production,” said Arthur Johnson, petroleum geologist and consultant for U.S. based Hydrate Energy International.
When deposits of gas hydrate are heated or when their covering is removed in an oceanic landslide or geologic event, the gas contained can be released.
“In a very small area, less than 10,000 square miles, we have counted more than 100 fountains, or torch-like structures, bubbling through the water column and injected directly into the atmosphere from the seabed,” said Igor Semilotov, one of the scientists working in the International Arctic Research Center of the University of Alaska - Fairbanks.
“One of the greatest fears is that with the disappearance of the Arctic sea ice in summer, and rapidly rising temperatures across the entire Arctic region, which are already melting the Siberian permafrost, the trapped methane could be suddenly released into the atmosphere leading to rapid and severe climate change,” Semilotov said.
Natalia Shakhova, of the International Arctic Research Centre at the University of Alaska - Fairbanks, is another of many scientists researching gas hydrates. “The concentration of atmospheric methane increased [nearly] three times in the past two centuries from 0.7 parts per million (ppm) to 1.7 ppm, and in the Arctic to 1.9 ppm. That is a huge increase, between two and three times, and this has never happened in the history of the planet,” Shakhova said.
“It would be great to capture the methane hydrates for energy before [they] decompose, that would be the best thing to do. If we do not capture it, and we let it to decompose, we first are going to lose some methane we are not using, and we are going to get some negative impacts on nature,” said Miriam Kastner, of the Scripps Institute of Oceanography of the University of California - San Diego.