In the wake of the Fukushima disaster, Japan has been on a focused mission to supplant their nuclear energy with safer alternatives (more like, non-radioactive alternatives).
It's been announced that a Japanese drilling ship has successfully extracted natural gas from a frozen methane hydrate deep beneath the Nankai trough seabed. Though the offshore extraction was only an experimental and non-commercial production of the energy-dense gas, the achievement is marked as a notable step in the research and development of methane hydrates as a valuable energy resource.
Methane hydrate deposits consist of an ice-like material of methane molecules surrounded by water molecules that thrive in low-temperature, high-pressure locations. Thus, much of the substance is generally allocated deep below the ocean floor, or under permafrost areas.
The news comes in the wake of Japan's recent nuclear turmoil that prompted Japanese government officials to immediately focus efforts on alternative and renewable energy sources. The methane hydrates located deep below the Nankai trough are said to contain enough energy to meet Japan's energy demands for the next 100 years! In fact, the company JOGMEC reports that the energy contained in a given volume of methane hydrate is 164 times the amount of energy contained in the same volume of conventional gas. What is even more astounding is that the amount of energy available from all of the world's methane hydrate deposits is far greater than the collective amount of energy that can be extracted from all other conventional sources.
To extract the gas, a Japanese company drilled a 300-meter-deep hole into the Nankai trough seabed. With direct access to the methane hydrate deposits, surrounding water was pumped out of the way and a pipe was placed above the hydrate. This effectively lowered the pressure above the hydrate and allowed the gas to escape upwards toward the ship. The gas was then tested on a burner on board the ship that caused a pair of propellers to spin upon successful extraction.
Of course, with such intrusive methods of hydrate energy extraction, there are still plenty of environmental challenges to be addressed before commercial production can become a reality. Work still needs to be done that will prevent the powerful greenhouse gas from escaping into the atmosphere. Deep offshore drilling could also potentially weaken the seabed floor, making landslide incidents a high possibility.
For now, the prospect of methane hydrate as an energy source is already moving countries into action. The US and Russia have already begun researching ways to harvest hydrates embedded under each country's respective permafrost region.