Burning methane hydrate. Image: Andreas Villwock/GEOMAR Helmholtz Centre for Ocean Research Kiel
Could methane hydrate help us move away from coal?
In 2006, China announced that it would spend 800 million yuan, at the time worth about $112.5 million CAD, researching frozen natural gas on the sea floor—combustible ice. Over a decade later, they've drilled for their first samples, paving the way for a possible shift away from fossil fuels.
Reports coming out of China now state that samples of the ice, which contains methane, have been collected in the South China Sea. The country's Minister of Land and Resources, Jiang Daming, called the findings a potential catalyst for a global energy revolution.
The concept of ice that can light on fire is disconcerting, so professor Maurice Dusseault, from the Earth and Environmental Sciences department at Waterloo University, broke it down for us. He started with the name: "We (meaning scientists) don't call it combustible ice," Dusseault said in a phone interview. "We tend to call it methane hydrate."
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Methane hydrate is a mixture of methane (a natural gas) combined with, maybe a little bit of other gasses like propane butane or ethane, and water. When the pressure and temperature are just right, this mixture turns into a crystalline substance, like ice. Dusseault said that this material is stable because the pressure near the sea floor is very high, holding the system together.
The methane itself comes from deeper down, under the ocean floor, but it's also not readily available everywhere. "Turns out that conditions on seafloors around the world are ideal for the formation of this methane hydrate," he said. "We even find this material underneath the land in Arctic Canada, where the conditions are also favourable because the temperature is so low."
One single piece of combustible ice gets about 20 percent of its weight from the methane, and as the ice melts that methane is released, Dusseault said. "This is why you can light it on fire."
A roadblock to using combustible ice as a power source is the fact that there's no economical way to mine the substance yet. "There has been no commercial project that has succeeded in exploiting this methane, but in the future this could happen," Dusseault said. There is currently research being done by the Japanese, Americans and Chinese where they're trying to develop economically sustainable ways to get the methane out of the ice.
The Chinese are interested in using combustible ice as an energy source because they'd like to use the found natural gas to replace coal-fired power plants, which Dusseault calls "evil". He cited other issues with coal, like how dangerous it can be to miners, groundwater and air pollution from coal mines.
Dusseault said he couldn't give an exact number to quantify how much of this ice is available. "But," he said, "the amount of natural gas trapped in ice in the sea floor is considered to be much more than the amount of natural gas we can exploit on land."
If humans could find a way of commercially producing the methane that exists in combustible ice, coal-fired power plants in the world could technically be replaced. And commercial mining of combustible ice could actually support the renewable energy movement, according to Dusseault.
"Eventually we will be consuming less natural gas if we can find the right technologies to store the energy from our renewable power, and maybe find new sources of power like nuclear power plants based on thorium rather than uranium," he said. "Natural gas has an important role to play in the transition from our fossil fuel heavy energy industry to some point in the future where we are carbon-lite."
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