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Efficiency drive
China's energy planners have realized that improving energy efficiency is the easiest way to promote economic growth while controlling pollution. "China should work first on this," says Dadi. Predictions that assume 'business-as-usual' suggest that total energy demands will rise to the equivalent of 3.5 billion tonnes of coal per year by 2020. But introducing a suite of measures to improve efficiency could keep that below 3 billion tonnes, says Dadi. "Technically, it's do-able."
This new drive for efficiency stems in part from a quietly influential initiative run by the San Francisco-based Energy Foundation. Bankrolled for a total of US$40 million since 1999 by the Hewlett and Packard foundations, the China Sustainable Energy Program is working with Chinese energy researchers to improve efficiency and cut pollution. Priorities include new efficiency standards for buildings, appliances and vehicles, and promoting renewable energy sources. Fuqiang Yang, who heads the Energy Foundation's Beijing office, points to recent successes such as the renewable energy law, plus fuel-efficiency standards and energy-efficient building codes adopted by central and local governments.
China's energy crisis is boosting interest in new technologies like coal liquefaction.
Energy efficiency is an admirable goal, but China's appetite for growth and the leadership's desire to limit imports of foreign oil mean it won't be enough. So China is embracing technologies that, in the West, remain on the fringes. Du Minghua, director of the Beijing Research Institute of Coal Chemistry, sees coal as an energy panacea, able to meet China's demands for electricity, liquid fuels and gas. "Coal is the solution for all three," he exclaims, before launching into a presentation on his institute's work on coal gasification and liquefaction.
Finding ways to reduce dependence on oil, critical for the transport sector, is the top priority for Minghua's institute. Young coals such as lignite can be converted straight to liquid fuels by heating them to 450 °C with hydrogen and a suitable catalyst, Minghua explains. Older coals such as anthracite must first be heated in oxygen to produce a mix of hydrogen and carbon monoxide known as syngas, which can then be converted into liquid fuels. Some of these can be blended with diesel and pumped straight into a conventional engine.
Despite Western experts' scepticism about the direct coal-to-liquid technology1, the state-owned Shenhua Group is now building the world's first commercial direct coal-liquefaction plant in Inner Mongolia, scheduled for completion by 2008. And China is also in discussions with the South African company Sasol about the possibility of building two large indirect liquefaction plants.
Crude substitute
Neither process is a model of efficiency, however. Direct liquefaction is about 60% energy-efficient, indirect techniques around 45%. But China's desire to seek alternative liquid fuels is so great that Minghua estimates that liquefaction technologies could be providing it with more than 50 million tonnes of fuel per year by 2020. "This is a personal estimate," he stresses — but one that will be music to the ears of China's leaders. If Minghua is correct, coal liquefaction could reduce China's demand for crude by 100 million tonnes per year, or about one-third of its anticipated imports by 2020.
Coal is also central to the thinking of researchers at the Tsinghua-BP centre. Zheng is focusing on a strategy called polygeneration in which a single plant would convert coal into syngas, then use it in gas turbines to generate electricity and also convert it into liquid fuels2. Sulphur is removed as an integral part of gasification, cutting pollution. To demonstrate the technology's potential, Zheng and his colleagues have conducted a 'syngas city' simulation for Zaozhuang in the eastern Shandong Province. Like many industrial centres in China, Zaozhuang faces a major problem: how to continue growing when the only readily available fuel is high-sulphur coal.
In the 'syngas city' model, the Zaozhuang authorities would provide incentives to promote polygeneration, which not only generates electricity but also produces methanol for vehicle fuel and dimethyl ether for domestic cooking and heating. The simulation suggests that polygeneration could meet more than a quarter of Zaozhuang's electricity needs by 2020. It would also achieve drastic cuts in sulphur dioxide emissions while reducing the need to invest in expensive flue-gas desulphurization technology at conventional power plants3. Further reductions in air pollutants, such as ozone-forming compounds, would come from the wider use of methanol and dimethyl ether.
Such simulations are the stock-in-trade of energy researchers worldwide. But in China there may be a greater chance of their being implemented, given the authorities' power to enforce their will. Preparations for the 2008 Beijing Olympics are a case in point. Realizing that the city's appalling air quality could damage athletes' health — and present a poor image of China to the world — the city is now engaged in a frantic clean-up, closing some 200 heavily polluting factories, piping in natural gas, and introducing a clean 'bus rapid transit' system. "The Olympics are a very big opportunity," says Li Hao, who heads EarthView, a Beijing-based environmental group.
Zheng and his colleagues hope that growing official concerns about environmental health will also boost their proposal to build a polygeneration demonstration plant, costing some 5 billion yuan (US$600 million), which would generate up to 400 megawatts of electricity and produce as much as 400,000 tonnes of liquid fuel per year. "We got a very good response from the government," says Zheng.
Greenhouse city
But while polygeneration and other clean-coal technologies may help to scrub China's filthy air, they won't do much in the short term to limit the nation's growing greenhouse-gas emissions. According to Zheng's simulation, total CO2 emissions from power plants would be higher for the syngas city than if Zaozhuang continues using conventional technologies3.
In the long run, however, polygeneration could provide a route to a more sustainable future, in which hydrogen is extracted from syngas and used to power fuel cells, while CO2 is captured and sequestered. "But to get there, the investment will be huge," warns Zheng.
Given the costs involved, experts say that China's interest in carbon sequestration will depend largely on the willingness of Europe, North America and Japan to pay for it. Those who work in the energy industry are blunt about China's determination to strike a hard bargain. If the necessary cash isn't forthcoming, they say, all deals are off.
China's potential to single-handedly emit enough CO2 to negate all other nations' efforts to control their greenhouse-gas emissions could place its leaders in a strong negotiating position. "If it's business as usual, then the planet is dead," says David Moskowitz, director of the Regulatory Assistance Project, based in Gardiner, Maine, who is advising Chinese officials on reforming the electricity-generation sector.
That should provide food for thought for the leaders of the G8 wealthy nations, who meet in Scotland in July with global warming on their agenda. China is a signatory to the Kyoto Protocol on climate change, but as a developing country it doesn't yet have an emissions reduction target. Whatever strategy world leaders contrive to save the planet, China will sooner or later have to be brought on board. And that won't come cheap.
[ Last edited by 灰鸦 on 2005-7-17 at 12:51 ] |
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发表于 2005-7-16 20:10
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