Future conflicts of water demands and availability in China’s power sector

Electricity use is indispensable for almost every aspect of modern human society, from agricultural and industrial production to household consumption. It is increasingly recognized that, besides hydropower, water resources are also required for thermoelectric power production that provides the majority of the world’s electricity use. Therefore, water security can have serious impacts on electricity security. Electric power curtailments caused by water-related issues have been reported all around the world. China, the world largest electric power producer, faces pronounced challenges in this respect as its electric power sector heavily relies on coal-fired power plants that are located at inland water ways. Water shortages may induce substantial cost for under-serving electricity to its large population and fast growing economy. However, such risks, including their magnitudes and spatiotemporal characteristics, are not well understood, especially under future climate change. Against this backdrop, this dissertation, for the first time, examines water shortage risks facing China’s electric power sector on plant-level and monthly bases within a comprehensive framework. It first develops a comprehensive inventory of plant-level water-using technology dataset and, based on which, quantifies the electric power sector’s water demands in China. Water availability is then simulated with a calibrated hydrological model that incorporates human interventions during the current period (1984-2014) and future period 2050s (2035-2065) under two carbon emission scenarios RCP 2.6 and 8.5. Spatial and temporal water risks can be identified where water availability falls short of water demands. Finally, using the concept of virtual water within the Input-Output framework, water uses for electric power productions are attributed to different end users whose electricity use could be disrupted should those above-identified risks arise. From 2000 to 2015, water withdrawal and consumption in China’s electric power sector, excluding hydropower, have increased from 40.75 and 1.25 billion m3, respectively, to 124.06 and 4.86 billion m3. Freshwater use withdrawal and consumption are projected to exceed 280 and 15 billion m3 respectively by 2050 if China does not implement any new policies, up from current levels of 65.2 and 4.64 billion m3 (2014). At a regional level, central and eastern China account for the majority of the power sector’s water withdrawals because open-loop cooling systems are widely adopted, while water consumption is significantly higher in the current dry northern regions because closed-loop cooling systems are more popular. It is found that around 10% of China’s coal-fired power capacity is facing low flow water risks from July to October, and 20% the rest of the year. Particularly in the north, 40% to 60% of its regional coal-fired power capacity is at risks of not having enough water for cooling purposes from February to June. Under climate change, available water in the river system is expected to increase significantly in the current dry north and decrease significantly in the northwest and slightly in the south, which is expected to alleviate the low flow water risks facing China’s coal power plants except in the northwest Inland River Basin. In the east and south, if their growing electricity demands continue depending on coal, increasing utilization rate of coal power facilities can lead to the increase of demand-driven water shortage risks. Lastly, this dissertation includes water consumption by both thermoelectric and hydropower plants to reveal the virtual water flows from power producers to consumers using Multi-Regional Input-Output analysis. From 2002 to 2012, the share virtual water embodied in the final consumption of electricity, e.g. household, increased from 24.6% to 39.8%. Nearly half (47.5% in 2010) of the physical water inputs into the power sector were virtually transferred across provincial boundaries in the form of virtual water embodied in the electricity produced, mainly from provinces in northeast, central and south China to those in east and north China.