Note this comment in the report: Commissioned by the US Department of Energy and written in 2007 by prominent scientists, the report concluded that geothermal power was the only renewable energy capable of replacing fossil fuel for electric power generation in the US.
China switching on to the power of deep heat Geothermal power is China's most plentiful, reliable and environmentally friendly renewable energy, and its most neglected - but that may be about to change Stephen Chen Jul 17, 2011 Email to friend Print a copy Bookmark and Share
Professor Wang Jiyang presented his passport to a guard at the military checkpoint at Los Alamos National Laboratory in New Mexico.
He arrived on a clear day in the summer of 1981.
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The guard leafed through the pages of the passport and cheerfully told the professor that he was the first visitor from mainland China.
Los Alamos was the birthplace of some of the world's most lethal weapons, including the first atomic bomb.
But that did not interest Wang, a geologist from the Chinese Academy of Sciences. What lured him there was hot dry rock.
In the early 1970s, researchers at Los Alamos had put up a huge facility at a place called Fenton Hill.
They had drilled a well thousands of metres deep and sent down pressurised water, fracturing the hot dry rocks and harvesting steam for power generation.
They told Wang that hot dry rock as a source of energy was almost unlimited, theoretically available anywhere, and absolutely clean.
Fast forward to the present day - Wang has received many phone calls from senior government officials, executives of state-owned oil companies, real estate developers and coal barons, asking him if hot dry rock was that good.
"Yes, it is," he said. "You should have called 30 years ago."
Geothermal power is China's most plentiful, reliable and environmentally friendly renewable energy. Compared to wind and solar power, it is also the most neglected.
But the increasing pollution from coal, reliance on imported oil, ecological intrusion of hydropower dams, safety concerns about nuclear reactors and the tiny amount of wind and solar have fuelled interest in enhanced geothermal systems, or hot dry rock.
China's recent geothermal fever was ignited by a report from the Massachusetts Institute of Technology.
Commissioned by the US Department of Energy and written in 2007 by prominent scientists, the report concluded that geothermal power was the only renewable energy capable of replacing fossil fuel for electric power generation in the US.
Humans have exploited geothermal power since the first hot-spring bath, but so far the energy has only been extracted where the heat source co-existed with a natural underground water pool, or geysers.
Miners knew that the deeper they dug the hotter the rocks became. They just didn't have a way to take the heat out. An enhanced geothermal power system solves the problem by creating an artificial water pool.
The system uses high pressure water or liquefied carbon dioxide to create fractures in hot dry rocks.
As the liquid flows through these fractures, it carries out the heat.
Hot dry rock could be a stable energy source for decades if the flow were controlled properly.
"Most of the key technical requirements to make EGS [enhanced geothermal systems] work economically over a wide area of the country are in effect," the report said. "Remaining goals are easily within reach."
In the wake of the report, the US Department of Energy set up a Geothermal Technologies Programme with a US$500 million budget last year.
Even Google invested more than US$10 million in hot-dry-rock research in 2008 - the company's only investment in renewable-energy R&D.
A retired former senior executive of PetroChina (SEHK: 0857, announcements, news) translated the nearly 400-page report into Chinese last year, starting the momentum in China, Wang said.
The central government plans to launch a national survey this year to map the depth and distribution of hot dry rocks on the mainland, he said. The Ministry of Land and Resources has consulted him about the project. "As soon as we have a reliable map showing the potential of the energy, we will take it to the leaders and ask for the money to start experimental drilling," Wang said.
Many interested investors have contacted him, but the scientist said the technology was still at the research stage and he did not encourage the participation of the private sector. Japan and European countries had built hot-dry-rock facilities without relying on private investment.
Because the underground system is extremely sophisticated and much technology is required, only a government could take the financial burden and risk, he said.
But Dr Graeme Beardsmore, technical director of Hot Dry Rocks, a company based in South Yarra, Australia, disagrees.
"The technology is ready for large-scale deployment," Beardsmore said. "There are certainly technological avenues for improving the performance of hot-dry-rock systems and decreasing their cost, but no major technological advance is necessary to start large-scale developments.
"Several years ago I did some preliminary investigations into the potential for HDR technology in southeast China and the potential looks to be as good or better than most other places in the world. In particular, there are large areas of granite in southeast China that potentially generate substantial amounts of natural heat that could be harnessed close to the areas of densest population.
"But development of hot-dry-rock resources requires a broad range of skills. There is only a limited number of people in the world with the experience and capability to efficiently carry out such a development."
Professor Zeng Jianhui, a researcher at the State Key Laboratory of Petroleum Resources and Prospecting, said China's oil companies had enough technology and experience for the job.
"The oil drilling sometimes goes deeper and is often more delicate. Drilling to reach some hot dry rocks is a piece of cake to Chinese oil companies," he said. "Taking the heat out with injected water won't be a problem, either. Some of our oilfields have already done that."
But Professor Wu Nengyou, deputy director of the Chinese Academy of Sciences' Guangzhou Institute of Energy Conversion, said certain unsolved technological problems limit the commercial production of hot- dry-rock projects.
The biggest problem, he said, was keeping the fractures open.
The facility at Fenton Hill was shut down in the end, partly because researchers failed to find an effective way of maintaining the fractures in the man-made pool, which was important for heat exchange. The fractures kept filling with substances ranging from calcium to salt.
Professor Melissa Schilling at New York University's Stern School of Business said geothermal energy was improving exponentially, but gets hardly any investment, partly because of oil companies.
"The companies that are likely best positioned to exploit geothermal energy [in terms of their existing capabilities, assets, and supply chain] are the oil companies," she wrote. "However, they have very little incentive to promote geothermal [power] while oil continues to be profitable."
Professor Duo Ji, of the Chinese Academy of Sciences, said instead of pouring money into the nuclear sector the government should invest in geothermal power.
"Geothermal power is almost a free gift from nature," he said. "It has been ignored."
