China announced yesterday it had made a breakthrough in excavating natural gas hydrate, the so-called “flammable ice”, which is believed to be a potential natural energy source. Zhang Hongtao, deputy director-general of China Geological Survey (CGS), said gas hydrate samples were successfully collected from the northern part of the South China Sea last month. China is the fourth country after the United States, Japan and India to make such a technological achievement. Zhang said the development was expected to ease the country’s dependence on oil and coal. Initial estimates indicate the potential volume of gas hydrates around continental slopes in the area exceeds 100 million tons of oil equivalent, Zhang said. The samples were collected from two different stations in the Shenhu (Magic Fox) continental slope on May 1 and May 15, he said. Nicknamed “flammable ice”, gas hydrates are crystalline solids, which occur when water molecules form a cage-like structure around smaller “guest molecules” of methane, ethane, carbon dioxide and other substances. Stable only at low temperatures and/or high pressures, gas hydrates are extremely fragile, and mainly exist either in the seafloor or below tundra at high latitudes. The resource has become a hotspot of international research in recent decades, as scientists believe gas hydrates are a perfect alternative fuel resource to oil and gas, writes China Daily.