Energy on Ice

Science News Online ^ | June 25, 2005 | Alexandra Goho

[alloysteel]

In March 2002, an international team of scientists pumped hot water down a 1,200-meter well located at the edge of the Mackenzie River Delta in northwestern Canada. The water seeped into the pores of the perpetually frozen sediments, melting icelike crystals along its path. These were no ordinary crystals, but frozen cages of water molecules filled with methane, the main constituent of natural gas. The structures had formed millennia ago and now reside in layers deep below the permafrost. As the crystals melted, the natural gas escaped and bubbled to the surface to fuel a flame rising high above the white Arctic landscape.

"It was a landmark effort," says Dendy Sloan of the Colorado School of Mines in Golden. It produced the first documented field demonstration that natural gas could be released from the crystalline substances known as methane hydrates.

At first glance, this unconventional source of natural gas looks like ordinary ice. But place a match next to the ice and it burns. Over the past several decades, scientists have identified dozens of gas-hydrate accumulations around the world (SN: 11/14/98, p. 312: http://www.sciencenews.org/pages/sn_arc98/11_14_98/bob1.htm). Some say that worldwide there could be twice as much energy stored in hydrates as in all the other known energy resources combined, including coal, oil, and conventional natural gas deposits.

As Timothy Kneafsey of the Lawrence Berkeley (Calif.) National Laboratory puts it, "Hydrates could be a giant source of energy in the future. It's something that's just waiting to happen."

[alloysteel]

Lengthy article, but well worth the read. As the technology develops, the fears about the "diminishing" supplies of fossil fuels will be shown to be misplaced.

The Russians are already developing their own pilot programs for recovering methane hydrate, and may be close to commercial breakthrough.

[chainsaw]

As the crystals melted, the natural gas escaped and bubbled to the surface to fuel a flame rising high above the white Arctic landscape.

Just a question - How many BTU of energy are needed to melt the ice to get out x number of BTU in methane gas.

[Wonder Warthog]

"As the technology develops, the fears about the "diminishing" supplies of fossil fuels will be shown to be misplaced."

What technology needs to be developed (demonstrated, yes, but not developed). This approach is not significantly different (and in fact is less demanding) from the way sulfur is currently "mined" by the Frasch process.

[Dark Wing]

FYI

[ImaGraftedBranch]

Just a question - How many BTU of energy are needed to melt the ice to get out x number of BTU in methane gas

Good question. Here is how I imagine you could do it without using external BTU's:

• Get a can of black paint.
• Paint a picture of a big carpentar ant on the ice where you want the hole.
• Get a BIG magnifying glass.
• Adjust magnifying glass so the focus-point of the photons are on the ant.
• Wait.

Periodically, you will have to adjust the magnifying glass, of course, but I can also picture a BTU-free mechanism for holding the magnifying lens using pulleys (as long as the post that is supporting the weight of the lens is on the spot where the ice is melting, the lens will move down and burn the appropriate new spot as the ice melts.

Of course, if you want to drill deep, you have to have a tall pole, which of course increases the required circumference of the lens proportionately.

(there's also that angle thingy to worry about as the planet rotates, but I've burned too many BTU's writing this already)

[EERinOK]

I recently had the good fortune to be in attendance at a short 3 hr seminar on this topic.

At present, the energy expended melting the ice, including the heat losses in the well transporting a warm fluid down to the ice, in fact does exceed the energy value in the recovered methane.

The other issue in the warm fluid circulation recovery is contact area. As you melt the hydrate and crate a small cavity, contacting hydrate is more difficult, hence less efficient.

Hydrates, when destabilized through temperature and pressure change, will break down on their own, releasing methane. It is this that the scientists are looking at more than the circulation technique. Depressurizing the deposits could be more efficient than trying to heat them up.

All in attendance concurred that hydrates as a large scale economical fuel source is at least 20, and could be 50 years away. Most thought that the Japanese would lead the way based on their complete dependence on foreign hydrocarbon fuels, abundant offshore hydrate deposits, and their current and planned investment budget for hydrate recoverty technology.