China looks to 'combustible ice' as a fuel source

Mar 12, 2010 by Lisa Zyga report
(Left) Methane hydrate consists of a cage of water molecules trapping a methane molecule within. Credit: Slim Films for Suess et al., Scientific American, Nov. 1999, pp. 76-83. (Right) When methane hydrate is brought to the surface, the methane can be burnt off. Credit: Gary Klinkhammer, OSU-COAS.

(PhysOrg.com) -- Buried below the tundra of China’s Qinghai-Tibet Plateau is a type of frozen natural gas containing methane and ice crystals that could supply energy to China for 90 years. China discovered the large reserve of methane hydrate last September, and last week the Qinghai Province announced that it plans to allow researchers and energy companies to tap the energy source. Although methane hydrate is plentiful throughout the world, the key challenge for China and other nations will be to develop technologies to excavate the fuel without damaging the environment.

Methane hydrate is an ice-like substance that is sometimes called “combustible ice” since it can literally be lit on fire and burned as fuel. But rather than dig up the substance, excavators would likely melt the ice underground first, and then extract the . However, researchers are still investigating the most appropriate way to extract the fuel for commercialization.

Methane hydrate is an attractive energy source due to its high energy density: one cubic meter of combustible ice contains about 164 cubic meters of regular natural gas. This high energy density is due to the fact that methane is trapped within the hydrate and greatly compressed. According to the DOE, the immense energy content of methane occurring in hydrate form may possibly exceed the combined content of all other known . In addition, the frozen hydrate has few impurities, meaning it can burn cleaner with fewer pollutants than oil and possibly regular natural gas, as well.

Combustible ice has already been discovered in more than 100 countries, buried in both the and beneath the . Besides China, countries including the US, Japan, and the Republic of Korea have plans to tap the natural gas hydrate buried in their territories. Last summer, US scientists on a research vessel in the Gulf of Mexico discovered pockets of highly concentrated methane hydrate estimated to contain 6,700 trillion cubic feet of gas. The DOE has estimated that the total amount of methane hydrate worldwide could be as high as 400 million trillion cubic feet, including 85.4 trillion cubic feet buried in Alaska.

Because methane is a potent greenhouse gas, researchers are also concerned about the environmental effects of extracting methane hydrate. However, if handled carefully, using methane hydrate as a fuel could be safer than simply letting it melt on its own. As the earth continues to warm, methane released into the atmosphere could cause even more damage than if it were burned for fuel. On the other hand, if large amounts of methane were accidentally released during extraction, the results could further aggravate global warming. Another risk from mining the combustible ice is geological slumping.

For these reasons, developing a safe technology to excavate the fuel is a priority. With these challenges in mind, China's Ministry of Land and Resources estimated last week that the country could begin using its combustible ice within 10 to 15 years, joining other countries in exploration.

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More information: via: Xinhuannet and the US Dept. of Energy

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User comments : 13

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krundoloss
3.3 / 5 (6) Mar 12, 2010
Ok, well the problem with Gas as an energy source has always been transporatation, with all those high pressure tanks and pipes. Why don't we leave this material the way it is, after all
"one cubic meter of combustible ice contains about 164 cubic meters of regular natural gas". So just leave it as a solid/ice and transport it, then melt it for energy. Its easy to melt it, so, problem solved. Just a thought!
stvnwlsn
3 / 5 (2) Mar 12, 2010
Methane and water. Wouldn't this be ideal for fuel cells?
El_Nose
4.5 / 5 (6) Mar 12, 2010
yeah leaving it as a solid sounds great until the refrigerator truck breaks down on the side of the road on a hot day --- then you have a very nasty bomb, first from vapor pressure increase then the energy density of the material.

Javinator
4.7 / 5 (6) Mar 12, 2010
yeah leaving it as a solid sounds great until the refrigerator truck breaks down on the side of the road on a hot day --- then you have a very nasty bomb, first from vapor pressure increase then the energy density of the material.



A low pressure pressure relief valve could fix that pretty easily as the situation you described would not lead to a flash boil of the "ice" and the pressure inside the truck would likely be around atmosphere most of the time since a solid is being transported and solids have very small vapour pressures.

Worst case you'd release the methane to the atmosphere. While that's bad for the environment as well as a waste of materials it's certainly better than an explosion.
Caliban
3 / 5 (4) Mar 12, 2010
Uh-oh. You would only be able to transport it as a solid in pressurized containers- it occurs in this state as a result of its formation underground, and therefore under pressure. Once heated or depressurized, it will vaporize/sublimate, and possibly explode.
On the other hand, it should be relatively simple to connect to the pipelines that already exist, in order to distribute it.
Main problem would be that you would still have to pay your Gas/Utility provider- so don't be looking for this to cause prices to drop- this would be a WINDFALL PROFIT BONANZA without equal in the history of human civilization. Quadrillions of cubic feet of this stuff!
Javinator
4.6 / 5 (5) Mar 12, 2010
There is a picture of it burning in solid state at atmospheric conditions in someone's hand at the top of the article.
Caliban
5 / 5 (3) Mar 12, 2010
Egregious error on my part. This goes entirely counter to what I thought I understood about the stuff. My apologies.
Glyndwr
3.3 / 5 (7) Mar 12, 2010
Good old china burning off methane....they are so advanced as a civilised nation......:S
hareontheriver
Mar 13, 2010
This comment has been removed by a moderator.
winthrom
not rated yet Mar 13, 2010
Consider that Methane gas is a feedstock for making gasoline by well known methods. The material could create some competition. Read that and weep Oil Cartel.
FenderFennec
5 / 5 (2) Mar 14, 2010
Repeat after me:

There. Is. No. Global. Warming.


Well, with an argument like that, how could anyone possibly believe in global warming?
kuro
5 / 5 (1) Mar 14, 2010
"the key challenge for China ... will be to develop technologies to excavate the fuel without damaging the environment."

Given the track record so far, please tell us what is the #2 challenge, because that will be the real key issue for the Chinar.
danlgarmstrong
not rated yet Mar 15, 2010
Build the poower plant on the Tibetan Plateau where the hydrates are. Transport electricity instead. If they can get those superconducting transmission lines going - so much the better.

The Tibetans might or might not like the idea, given the political situation there.
JCincy
3 / 5 (2) Mar 15, 2010
Repeat after me:

There. Is. No. Global. Warming.


The incentive to not allow any methane to escape is simple: Methane = Fuel = Money.

That's a far stronger incentive then the scientific fairy tale of global warming.