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China must manage the conflict between coal and water

Presented by E_G Date:2013-9-10 02:47 求翻译

  New coal-fired power plants in water-stressed regions could threaten water security for China's farms and communities

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In July 2012 China proposed building 363 new coal-fired power plants, 23% of which would sit in areas with "high water stress". Picture: WRI

  China faces a serious conundrum. The country, already the world's largest coal consumer, wants to significantly increase its coal electricity generating capacity in order to expand its economy. But this introduces a critical resource concern: more than half of the proposed plants will depend on water resources that are under high or extremely high stress.

  In July 2012, China proposed building 363 new coal-fired power plants. These plants would have a combined generating capacity exceeding 557 gigawatts, an almost 75% increase on current capacity.

  Researchers at the World Resources Institute recently overlaid the locations of those proposed coal plants on its Aqueduct water stress maps for China. Of the proposed plants, 23% sit in areas where 40% to 80% of available water resources are already in demand from other users – areas known as facing "high water stress". And 28% would be built in regions where other users compete for more than 80% of existing water supplies – areas deemed to be facing "extremely high water stress".

  New plants could potentially threaten water security for China's farms, the country's largest water user, as well as other industries and communities.

  Six provinces in particular will feel the strain. About 60% of the total proposed coal capacity is planned for Inner Mongolia, Shaanxi, Gansu, Ningxia, Shanxi, and Hebei. Those provinces only contain 5% of China's total water resources. And 60% of the proposed coal-fired power plants in those provinces are slated to be developed in areas of high or extremely high water stress.

The resource conflict: coal power and water stress

  Coal power plants and their supporting industries are especially dependent on water, which makes this finding particularly concerning. Mines use water to extract, wash, and process coal. Power plants need water to create steam and cool generating systems. If China's plans come to fruition, coal mining, coal-to-chemical production, and power generation could withdraw as much as 10bn cubic meters of water annually by 2015, according to a recent Greenpeace China report. That's more than one-quarter of the water available for withdrawal every year from the Yellow River.

  China's coal-fired power challenges are exacerbated by global and national climactic and demographic trends that shape the country's water supply and demand.

  China is relatively dry. On average, 1,730 cubic metres of water is available per person every year. That may sound like a lot, but it is close to the United Nations' baseline for water stress – the point at which there might not be enough water to meet total demand from homes, industries, agriculture and the environment.

  Resources are also unevenly distributed. The coal-rich north is one of China's most water-stressed regions. Since 2000, national water resources have declined, while the population grows and urbanisation explodes.

Existing and emerging solutions

  The Chinese government has realised it has a problem on its hands, setting national goals for water in 2012, called the Three Red Lines. This three-point plan calls for limiting annual maximum water use in the country to 700bn cubic meters (about 25% of annual available supply); increasing irrigation use efficiency to 60% by 2030 (irrigation use efficiency is currently at less than 50%); and protecting water quality to maximise sustainable development

  The Red Lines are an important first step. But China must go further to manage the water-energy collision in its coal industry if it's actually going to meet these water-cap targets. The country should slow down coal development overall while implementing a mix of water-saving and efficiency programs. Getting this balance right will be difficult.

  In some regions the local government has set compulsory requirements for new coal-fired plants to install technology such as closed-cycle and air-cooling loops, which withdraw less water than once-through systems. However, such equipment introduces additional trade-offs: water conservation cuts down on production efficiency by 3-10%, and bumping up greenhouse gas emissions.

  No single reform will allow China to expand coal production and meet its water use targets. These trade-offs between economics and natural resources will require careful attention for years to come. Prioritising water resources management will, however, put China in a better position to make those difficult decisions.

  Tianyi Luo is a research assistant for Aqueduct project at World Resources Institute (WRI), Betsy Otto is director of Aqueduct and Andrew Maddocks works in outreach and development at Aqueduct

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