BETHESDA, MARYLAND –

At the end of April, the China Geological Survey, a state-owned research agency specializing in mineral resources, dispatched two research submersibles on a three-day mission to explore methane hydrate in a northern part of the South China Sea. The mission followed up on the nation's first discovery of an active gas hydrate deposit in that area in 2015. It is unclear how the two projects relate, but China also agreed to a $40 million contract in February with a Dutch engineering company to begin field research into flammable ice in the South China Sea sometime in mid-2018.

Methane hydrate, also known as "gas hydrate" or "flammable ice," is an ice-like substance composed of methane gas and water. In theory, as long as methane is separated from other compounds, it can be utilized as a good source of energy. In reality, however, the gas has proven very technically challenging to extract and find in nature. Gas hydrate deposits are often located either beneath permafrost or the sea floor. Proactive methane extraction can also lead to serious environmental impacts, for example climate change tied to the escape of methane, a greenhouse gas, into the atmosphere. Relatively low prices for conventional and shale oil and gas in the recent market have also made flammable ice less attractive because of its high short-term production costs.

Due to these challenges, industry experts expect large-scale commercialization of methane hydrate won't occur until at least 2030. Nevertheless, several Asia-Pacific countries, including China, Japan, the United States and India, have actively invested in gas hydrate research that aims to utilize the substance as an energy source. While estimates of the global inventory of gas hydrate vary widely, global supply could exceed "the combined energy content of all other known fossil fuels," according to the U.S. Department of Energy.