Water−Carbon
Trade-off in China’s Coal
Power Industry
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Abstract
The
energy sector is increasingly facing water scarcity constraints
in many regions around the globe, especially in China, where the unprecedented
large-scale construction of coal-fired thermal power plants is taking
place in its extremely arid northwest regions. As a response to water
scarcity, air-cooled coal power plants have experienced dramatic diffusion
in China since the middle 2000s. By the end of 2012, air-cooled coal-fired
thermal power plants in China amounted to 112 GW, making up 14% of
China’s thermal power generation capacity. But the water conservation
benefit of air-cooled units is achieved at the cost of lower thermal
efficiency and consequently higher carbon emission intensity. We estimate
that in 2012 the deployment of air-cooled units contributed an additional
24.3–31.9 million tonnes of CO<sub>2</sub> emissions (equivalent
to 0.7–1.0% of the total CO<sub>2</sub> emissions by China’s
electric power sector), while saving 832–942 million m<sup>3</sup> of consumptive water use (about 60% of the total annual water
use of Beijing) when compared to a scenario with water-cooled plants.
Additional CO<sub>2</sub> emissions from air-cooled plants largely
offset the CO<sub>2</sub> emissions reduction benefits from Chinese
policies of retiring small and outdated coal plants. This water–carbon
trade-off is poised to become even more significant by 2020, as air-cooled
units are expected to grow by a factor of 2–260 GW, accounting
for 22% of China’s total coal-fired power generation capacity