China's rising hydropower demand challenges water sector

Area of Science:

• Environmental Science
• Water Resource Management
• Energy Policy

Background:

• Growing demand for hydropower in China, coupled with increasing global climate change concerns.
• Limited understanding of the water footprints (WF) of reservoirs and hydropower, and their contribution to water scarcity.
• China's policy to increase hydropower generation by 70% by 2020, intensifying pressure on freshwater resources.

Purpose of the Study:

• To calculate the reservoir and hydropower water footprints in China.
• To assess the contribution of reservoir WFs to water scarcity across major Chinese river basins.
• To analyze the implications of China's hydropower expansion on water use sustainability and the water-energy nexus.

Main Methods:

• Utilized data from 875 representative reservoirs in China, including 209 with power plants.
• Calculated reservoir WFs based on evaporation rates and hydropower WFs per unit of energy produced.
• Assessed the impact of reservoir WFs on water scarcity in ten major Chinese river basins.

Main Results:

• In 2010, the reservoir WF was 27.9 Gm(3), constituting 22% of China's total water consumption.
• Reservoir WFs contributed to annual water scarcity in 6 out of 10 major river basins.
• The hydropower WF was 6.6 Gm(3) yr(-1), with 3.6 m(3) of water consumed per GJ of electricity generated.

Conclusions:

• Ignoring reservoir WFs leads to a significant underestimation of human water appropriation.
• China's expanding hydropower sector exacerbates water scarcity, highlighting the critical need for sustainable water management.
• Strategic planning and trade-off analysis are essential for balancing energy demands with freshwater sustainability in the context of the water-energy nexus.