What are gas hydrates made of?

Natural gas hydrates are crystalline structures resembling ice, where gas, predominantly methane, is enclosed within water molecules. Unlike the ice we commonly know, composed solely of water, these hydrates are highly combustible, making them both a potential energy resource and a possible danger.

Hydrates hold significantly more natural gas than traditional reserves. The U.S. Geological Survey estimates that global gas hydrate reserves could be up to 10 times the volume of conventional natural gas deposits, with between 100,000 and 300,000,000 trillion cubic feet still to be discovered.

If we can find a way to extract gas from these reserves safely, efficiently, and affordably, gas hydrates could become a major alternative to coal and oil as the world’s primary energy sources. But that's a significant challenge to overcome.

The Search for Hydrates

While methane hydrates can be located in permafrost, the vast majority of gas hydrates are situated thousands of feet — at least 1,600 feet — beneath the ocean’s surface, where gas molecules crystallize in the cold depths of the sea.

Due to the extreme depths at which these potential energy resources are located, much of the data on the composition and quantity of gas hydrates remains unknown. Researchers believe that these hydrates often form along continental fault lines, with inferred locations of large gas hydrate deposits. However, the lack of precise knowledge about where to search, what resources might be found, and the best methods for extraction complicates any efforts to access this energy source.

Frozen Fuel: Burning Ice

Similar to other fossil fuels, gas hydrates are made up of hydrocarbon chains containing carbon and hydrogen. According to William Harris from Mytour.com, gas hydrates contain “twice as much carbon as Earth’s other fossil fuels combined.” To put it in perspective, just 1 percent of natural methane hydrates could fuel the United States for 170,000 years, Harris reports. With significant reserves of deep-sea gas hydrates off the coast of Alaska, the U.S. could potentially achieve energy independence through this resource.

In an article by AFP from the summer, it was reported that Japan, a country currently reliant on foreign fossil fuel imports to meet its energy requirements, is set to carry out the first-ever offshore extraction of deep-sea hydrates. The initial drilling tests are scheduled to begin in 2013. In Canada, a Japanese-developed technology was first used in 2008 to extract methane from gas hydrates found in permafrost.

Though these efforts are still in the early research phase, large-scale commercial extraction of gas-hydrate reserves is expected to be at least ten years away.

The Hazards of Hydrates

On the evening of April 20, 2010, a methane gas bubble, originating from gas hydrates deep in the Gulf of Mexico, traveled up the drill column of the Deepwater Horizon oil rig, expanded as it neared the surface, and caused an explosion. The blast claimed the lives of 11 individuals, including two engineers and nine crew members. It took five months to contain the oil spill, marking one of the most catastrophic environmental disasters in U.S. history.

The tragic events of the Deepwater Horizon rig demonstrate the volatility of methane hydrates, which already pose significant hazards to current deep-sea oil drilling operations. Although oil companies once avoided drilling in areas with gas hydrates, this practice has become more common over the past 10 to 15 years, according to Eric Niiler of Discovery News. This shift could increase the likelihood of disasters similar to the Deepwater Horizon incident.

This is just one aspect of existing rigs. Drilling operations aimed at extracting methane from hydrates must address the volatile nature of the gas, particularly how it expands as it moves from high-pressure depths to the lower-pressure surface.

Lastly, methane is a potent greenhouse gas. While it could be used for clean-burning energy, methane released into the atmosphere is even more damaging to the environment than carbon dioxide. To prevent both environmental disasters and ensure efficient extraction, any attempts to harness gas hydrates as an energy source must minimize leaks.