Scientists collect HDR under Earth's surface

Chinese scientists have successfully excavated and collected hot dry rock (HDR) beneath the Earth surface in Northwest China's Qinghai Province, which analysts said could become a potential clean energy resource for China in the future.

The HDR of 236 C was collected under 3,705 meters beneath the surface of the earth in Gonghe Basin in Qinghai, making it the deepest-level and highest-temperature HDR ever collected by Chinese scientists, CCTV reported on Wednesday.

"The HDR is a new energy source that can be used to generate electricity," said Zhang Senqi, chief of the geothermal department of the Center For Hydrogeology and Environmental Geology under the China Geological Survey (CGS).

"It is often buried under the earth with a depth of at least 3,000 meters, and has a temperature above 150 C," Zhang told the Global Times on Wednesday.

Zhang and this geographic team have been working in Qinghai on the HDR for three consecutive years.

The HDR is scattered almost all over the world. The energy contained in the HDR at a depth of 3-10 kilometers could be 30 times that of petroleum, natural gas and coal, according to a report by the Science and Technology Daily on Saturday.

The CGS under the Ministry of Land and Resources said that China's HDR reserves might amount to 856 trillion tons of standard coal equivalent, among which 17 trillion tons could be excavated and collected, CCTV reported.

"The Tibetan plateau, especially the South Tibet region, has the rich deposits of the HDR with high temperature," Zhang said.

"The HDR, clean and recyclable, could be a potential energy source for China, which lacks energy resources," Lin Boqiang, director of the China Center for Energy Economics Research at Xiamen University, told the Global Times on Wednesday.

Zhang said that compared with the traditional hydrothermal and geothermal, the HDR is solid with higher temperature and rich energy content. "Moreover, the exploitation of HDR would not cause environmental hazards and will be hardly impacted by environmental factors."

Zhang added that some countries, such as the U.S., have begun research on HDR since the 1970s.

According to a Xinhua News Agency's report in 2014, only a handful of countries including the U.S., Japan and Sweden have mastered the technology regarding power generation using HDR.

"However, the utilization of the HDR for energy has a long way to go due to constraints of available technology means, including difficulties to collect the HDR and how to convert it into power," Lin noted.

"The theory of the HDR has existed for a long time, but since it has no market currently, few scientists are researching it," Lin said, adding that the country need to pay more attention on it.