January 2002

Hitting the Natural-Gas Jackpot

There may be enough natural gas on earth to meet our energy needs for thousands of years. The trick is to ferry it across continents without blowing up.

By David Voss

Compared to oil, natural gas is so abundant it's staggering. Proven petroleum reserves are good for another one trillion barrels or so. At today's rate of consumption, they will last about 40 years. Add in oil reserves thought to exist but still undiscovered, and the timeline stretches out some 160 years.

Known reserves of natural gas, which is composed mainly of the simple hydrocarbon methane, will last for about 50 years at today's consumption rate. Estimates of likely but as yet undiscovered gas resources extend that projection to about 200 years. But when the natural gas thought to lie buried deep under the ocean in methane hydrates is added in, the potential is mind-boggling. Hydrates, ice crystals that trap methane molecules, form below a depth of 300 meters as a result of methane-producing bacteria. Very little is known about how much gas is bottled up in these crystals or how to get it out, but best guesses are that the reserves could, even with natural-gas consumption rates doubling over the next several decades, last tens of thousands of years.

However you do the arithmetic, there's a lot of natural gas out there. Adding to its attractiveness as the fuel of the future is that methane is far cleaner burning than oil. But there's a big problem: natural gas is volatile and expensive to transport. One of the beauties of oil is that you can pour it down pipes, load it onto tankers or barges and safely ship it around the world. Natural gas, by contrast, is most often shipped as a liquid, which must be maintained at a temperature of -130 C or at tens of atmospheres of pressure. It can also be transported as a gas in pipelines, but because the gas must be kept compressed, that is an expensive proposition: one estimate is that a pipeline to get gas out of Alaska and into the Lower 48 would cost around $15 to $20 billion to build.

Throw in the fact that many large reserves are in remote locations like Alaska's North Slope or Siberia, and the result is that much of the world's natural gas is now commercially worthless. "Of the [natural gas] that everyone agrees is there, over half has absolutely no market [value]," says Mark Agee, president of Syntroleum, a Tulsa, OK, energy firm. "None whatsoever. It's in places like the northwest shelf of Australia, Papua New Guinea, the west coast of Africa, the North Slope of Alaska. Really remote places with no ready market close by."

For a chemical engineer, the solution to this quandary, in theory at least, is relatively simple. If you could chemically transform this dangerous gas into a liquid hydrocarbon, like synthetic oil or even gasoline, it could be transported easily and cheaply at room temperature and normal pressure. These synthetic fuels could flow right into existing oil pipelines or be put aboard tanker ships bound for market. After further refinement, they could even be distributed through the existing network of service stations. As an added bargain, since the starting material is virtually-zero-sulfur natural gas, the resulting fuels would also be free of the sulfur and aromatic pollutants that taint other petroleum products. You would, in other words, have a readily available source of fuel that is potentially far cheaper and cleaner than oil.

Some of the world's largest oil companies are now investing billions of dollars to build refineries that use "gas- to-liquid" technology to convert methane into ultraclean diesel and gasoline fuels. Using high-pressure, high-temperature refinery processes, these new plants, which are being constructed in places such as Bintulu, Malaysia, will turn natural gas into liquid products that are easily shipped to market and quite likely cost-competitive with petroleum products.

But some researchers believe they have a far better idea. The processes used at the new plants are based on chemistry that dates back to the early 1920s and are costly and inefficient. A small group of chemists and chemical engineers is working to discover catalysts-materials that speed up chemical reactions but are not themselves consumed in the process-for directly converting natural gas into liquid fuels at low temperatures and pressures. If these catalysts work-and that is still a giant if-they will make possible cheap, simple refinery processes that could unleash the vast untapped reserves of natural gas. Indeed, they would force experts to redo their calculations of the world's energy supplies. Suddenly, the untapped methane resources in Siberia and northern Canada could be just as important to the world as the vast oil fields of Saudi Arabia.