Published Dec 5 2008 by Energy Bulletin
Archived Dec 17 2008

Methane Hydrates: What are they thinking?

by Richard Embleton

The world's governments are beginning to come to grips with the reality that crude oil is a finite resource. That forces them to face another reality. The amount of that resource available for running global human society is about to go into terminal decline. We are at or soon to arrive at peak oil. Many analysts believe, based on the data, that we hit that peak in the spring of 2005. Other more optimistic analysts believe that peak may still be as much as thirty years in the future. Even that (I am not conceding that projection. I am in the spring 2005 camp.) is close enough that the majority of people alive today will have to begin to adjust to declining global oil production in their lifetime.

Optimists point to the fact that we have moved beyond various energy sources, on which the entire society depends, many times in the past. We have always found a new, better energy source to replace them. Even since the beginning of the industrial revolution we have moved through water power, steam power, coal, natural gas, electricity, oil and nuclear. Oil, however, has been the most important and workable energy source that we have ever discovered and exploited.

Where do we go from oil? What will be the next, better energy source that can power human society. There are many who see electricity playing an increasingly important role, including driving transportation. To many that electric future will be increasingly centered on a nuclear energy renaissance. On the fringes they see electricity generation from wind, solar, geothermal, tidal, hydro, wave and a variety of other options.

But oil is used for much more than powering the family car. I have trouble visualizing electric planes and electric ships. Hell, most electric cars have a battery range of under 100 kilometers. And I don't think you can make plastics from electricity. Last I noticed it required hydrocarbons.

In one form or another, in fact, hydrocarbons have been the world's primary energy source since the beginning of the Industrial Revolution over 200 years ago. It answers one extremely important need; portability. Hydrocarbon fuels, especially oil and its derivatives, can be easily move from one place to another. They can also be used on board to generate the power used to move it.

What is the next energy source that will give us what oil, coal and natural gas give us today? You may be surprised to hear that it may be the other hydrocarbon fuel. A Great many scientists, industry leaders and governments throughout the developed world believe that will be methane. More specifically they believe it will be methane hydrates.

Methane hydrates (also called clathrates) are bubbles of methane gas trapped in a cage of ice crystals. Methane hydrate deposits occur in locations all over the world. The most concentrated deposits occur under the Arctic Ocean, under the ocean floor on most continental shelves, in locations like the Gulf of Mexico, the Bermuda Triangle, the Dragon's Triangle south of Japan, and in permafrost surrounding the Arctic ocean. It is reliably estimated that the amount of methane trapped as hydrates globally exceeds by many times the total combined oil, coal and natural gas reserves that have ever existed on earth.

A chunk of methane ice exposed to the air and ignited will burn until all of the methane in that ice has been consumed. Methane hydrates, however, require specific conditions of temperature and pressure to keep them contained within their ice cage. Reduce the pressure - for example, by reducing the sea level and the pressure of water above the deposit - or increased the temperature and the methane hydrate deposit becomes unstable and begins to release the trapped methane into the atmosphere.

That is a problem. Methane is a greenhouse gas. In fact, it is 21-23 times more powerful as a greenhouse gas than carbon dioxide. When the methane trapped in the hydrate is released it expands by about 170 times.[1] Methane is lighter than CO2, lighter than air. As a result it rises rapidly through the atmosphere up to the lower-density stratosphere. On the positive side methane remains in the atmosphere for only about 10-20 years. CO2 remains in the atmosphere for over 100 years.

Scientists studying global warming have long been seriously concerned about the possibility of large scale methane hydrate destabilization and methane release into the atmosphere. The greatest concern is about the large volumes of methane hydrates under the Arctic sea floor and that trapped in the vast permafrost zone surrounding the Arctic Ocean. That concern has now been heightened by recent discoveries of hundreds of methane plumes on the floor of the Arctic Ocean north of Norway and Siberia. [2] There is also evidence in pock-marked sea floors of large releases of methane plumes in the geological past. [3]

Paleoclimatologists now believe that large scale, natural methane hydrate releases have been partly but significantly responsible for short-cycle global warming and global cooling cycles in the past. The recent discoveries in the Arctic, in fact, are thought to suggest that methane releases have contributed to the global warming that has occurred since the last ice age 15,000 years ago. [2]

The problem is that these methane releases have a strong positive feedback loop. As they increase the warming of the atmosphere that warming in turn increases methane release which in turn increases warming which in turn releases more...... You get the picture. Acceleration of global warming through this positive feedback loop, by increased methane concentration in the atmosphere, far more than CO2 concentrations, represents, to paleoclimatologists, a far greater risk of pushing us into the Venus effect, runaway global warming.

When it comes to satisfying the world's energy lust, however, caution may be thrown to the wind. Powering down human society is never an option put on the table when politicians and other leaders discuss energy policies and strategies. We have proven over and over again that business as usual is the only model that will be considered. How else can we explain the tar sands, oil shale development, deepwater oil extraction, coal mines extending out under the sea floor, and more?

There are various technologies under consideration for extracting methane from hydrate deposits. Most involve some form of heating the hydrate deposits - one, probably the dumbest and most dangerous, even goes so far as to suggest using nuclear explosions beneath the deposit to heat it, also suggested by some as a means of releasing oil from tar sands and oil shale - causing them to release the methane which is then collected and piped to a processing facility of holding tank. Proponents of methane hydrate exploitation, conscious of environmental concerns, are quick to offer reassurances like ".....tapping into the gas hydrates assessed in the study is not expected to affect global warming, said Brenda Pierce, coordinator for the USGS Energy Resources Program." [4] The louder and more frequent such reassurances are, of course, the more it suggests they are trying to cover up the probability that the result will be the opposite.

There are many projects underway, funded by governments throughout the world (Japan, India, China, South Korea, Russia, Norway, Canada, the U.S.), aimed at developing commercially viable technologies for exploiting the planet's vast methane hydrate deposits. The selection of sites for these projects are, themselves, a clear indication of one of the primary roadblocks to using methane hydrates as a societal-supporting energy source. They have sought out test sites with high methane hydrate concentrations.

Most hydrate deposits are too small or too dispersed to be commercially exploited. Also, unlike oil and natural gas, those deposits are generally not capped in such a way that the geology can be used to contain releases. Most of those deposits on the sea floor, in fact, exist in unconsolidated, sandy or silt sediment. The geology surrounding them is inherently unstable, difficult to contain. Once the deposit, or any large portion of it, is destabilized it is very difficult to prevent unintended, uncontrolled methane releases into the atmosphere.

Okay. I very begrudgingly accept that our leaders are not going to consider powering down as a potential tactic in the face of our impending energy crisis. Sooner or later the human race is going to have to accept that reality but clearly society is not prepared to accept it now. But methane hydrates are not like the other fossil fuels. And our approach to exploiting them is going to have to be very different. The risk to the climate and the environment is so much greater than has ever been the case with other fossil fuels. Most importantly, methane hydrates are globally affected by exactly the same constrains; temperature and pressure.

Global warming itself - it doesn't matter whether it is naturally occurring or caused by human combustion of fossil fuels - is the greatest threat of tipping methane releases into a runaway warming mechanism. Scientists do not know with any certainty yet how much of a global temperature rise is necessary to reach the tipping point where methane hydrate release into the atmosphere accelerates out of control. They do know that once that happens the acceleration will be self-sustaining and self-accelerating.

If our leaders take the same cavalier approach with scientific warnings about runaway methane release that they have taken with warnings about CO2 buildup in the atmosphere, and the long-term, safe storage of spent nuclear fuel, we are headed toward a much more serious atmospheric and climatic disaster than global warming experts have thus far suggested. Methane releases from the ocean floors and from Arctic permafrost have not been built into any of the current global warming models as a factor, including those models supporting the IPCC reports. Considering that methane hydrate deposits exceed the total of all other fossil fuels by magnitudes and that methane is more than 20 times more powerful as a greenhouse gas than CO2, that should be extremely worrying to anyone who accepts the validity of the global warming theory.

Other material;

1) Starting A Runaway Global Warming Process
2) Hundreds of methane 'plumes' discovered
3) A large methane plume east of Bear Island (Barents Sea): implications for the marine methane cycle
4) Study: Tap natural gas from Alaska's frozen areas

~~~~~~~~~~~~~~~ Editorial Notes ~~~~~~~~~~~~~~~~~~~

Originally appeared on Richard Embleton's blog, Oil, be Seeing You

More by Richard Embleton on methane hydrates:

The real problem with Methane Hydrates is Sliding under the Radar (Dec 17, 2008)

Methane hydrates: the next great energy source? (Dec 19, 2006)


Original article available here