Mining Methane Hydrates

From the March 2013 EcoNet News:

Big news. The Japanese have reportedly successfully mined methane hydrates 50 miles offshore in the Sea of Japan in the Nankai Trough. This is potentially really good news for Japan: It's been two years since the earthquake that crippled its Fukushima nuclear power plant. The country has no traditional fossil fuels and is looking at importing more oil and gas to balance its reduction in nuclear power.

Methane hydrates may represent a new and exciting source of energy. A form of "clathrates," they are a "frozen cage of molecules" of methane and water sometimes known as "burnable ice" or "solid natural gas."

Clathrates are at the nexus of chemistry and geology. Methane hydrates are found in both terrestrial and marine applications. They are hosted in sediments, within and beneath permafrost. Marine hydrates are potentially very important, but costly to recover. Canada had research successes in 2007 and 2008 but abandoned efforts due to cost.

A chemist first experimented with this class of compounds in Cornwall, England in the 1820s. Each clathrate is a guest compound locked inside the lattice structure of a host. They were a laboratory curiosity. Later they were a nuisance, clogging natural gas pipelines.

In the 1960s, "solid natural gas" was found in the Messoyakuka gas field in western Siberia, the first time it was found in a naturally occurring state. In 2003, researchers found methane hydrates 15 miles off the California coast, in the Santa Monica basin. They were found near the summit of an 800 meter undersea volcano.

Japanese proponents now hope to commercialize the technology by 2018. And the promise of large quantities is alluring. Scientists are using a depressurization method to transform the hydrates into methane gas. Japanese researchers believe there is at least a decade's worth of natural gas for Japan in the deposit.

But there are concerns about these laboratory phenomena: No one knows how much of it there is. What if there are large releases and the "disassociation" of the methane from its crystalline form? This could trigger undersea landslides. Given methane's high global warming potential (21 times that of carbon dioxide), a release triggered by change of temperatures or a change of pressure could cause abrupt climate change events. Methane hydrates are an unknown variable in the carbon equation.