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In China, electricity transmission has increased rapidly over the past decades, and a large amount of virtual water is delivered from power generation provinces to load hubs. Understanding the evolution of the virtual water network embodied in electricity transmission is vital for mitigating water scarcity. However, previous studies mainly calculated the virtual water transferred in short periods in low-spatial resolution and failed to reveal driving forces of the evolution of virtual water. To solve this problem, we investigated the historical evolution of the virtual water network and virtual scarce water network embodied in interprovincial electricity transmission between 2005 and 2014. The driving forces of the evolution of virtual (scarce) water networks were analyzed at both national level and provincial level. The results show that the overall virtual water transmission and virtual scarce water transmission increased by five times, and the direction was mainly from southwest and northwest provinces to eastern provinces. Sichuan, Yunnan, and Guizhou played an increasingly important role in virtual water exporting, and northwestern provinces had dominated the virtual scarce water exporting in the decade. At the national level, the increase of virtual water is mainly driven by the change of power generation mix and power transmission. At the provincial level, the increase of virtual water transmission in the largest virtual water exporter (Sichuan) is driven by the power generation mix and the power transmission, between 2005 and 2010, and 2010 and 2014, respectively. Considering the expanding of electricity transmission, the development of hydropower in the southwestern provinces and other renewable energies (solar and wind) in the northeastern provinces would overall mitigate the water scarcity in China. [ABSTRACT FROM AUTHOR]

The spatial mismatch between energy resources and water resources has been widely concerned. Electricity trade drives virtual water flows from electricity production sides to consumption sides, which can aggravate or alleviate regional water scarcity. Investigating the historical evolution of virtual water transmission and its impacts on water scarcity benefits the sustainable development of energy and water. To reduce data uncertainties, in this study, we built provincial water intensity of electricity generation inventory considering the impacts of factors such as electricity generation types, cooling technologies and generator units. Besides, to investigate how the direction and quantity of virtual water flows aggravate or alleviate the regional water scarcity, the impact assessment model was built, and the impact assessment index was defined. The results showed that the water consumption of electricity generation and interprovincial virtual water transfer increased by 2.61 times and 5.12 times during 2005–2015, respectively. Changes in the amount of electricity generation and the electricity transmission structure were the two main drivers of increases in virtual water flows, contributing to a total increase of 85.28%. A large amount of virtual water was transferred from the southwest and the northwest to the eastern coastal areas. There were many "positive flows" from the southwest to Jiangsu-Zhejiang-Shanghai, while "negative flows" were concentrated in Xinjiang-Henan, Gansu-Qinghai and Gan-Shaanxi. The nodes with the largest impact assessment index value were Hubei, Sichuan and Shanghai, while the lowest were Gansu, Xinjiang and Qinghai. This study can provide a basis for optimizing the electricity generation mix and electricity transmission structure, alleviating the growing tension between energy and water, and realizing the sustainable development of water resources. • The provincial water intensity for electricity generation inventory is built. • The amount of virtual water flows increased 5.12 times from 2005 to 2014. • The virtual outflows of the southwestern regions alleviated national water scarcity. [ABSTRACT FROM AUTHOR]

Along with electricity transmission, virtual water is transferred from electricity generation provinces to load hubs, reallocating spatial water resources and impacting regional water scarcity. To assess whether virtual water in electricity transmission mitigated or aggravated national water scarcity, a rationality assessment model was proposed from energy-water nexus perspective. The interprovincial virtual water flows were calculated based on provincial water intensity and electricity transmission considering the provincial electricity generation mix. The flow rationality index and node rationality index were proposed and defined to evaluate the net benefit of virtual water flows and provinces, respectively, according to the interprovincial differences in water stress index. The results show that: 1) a large amount of virtual water was transferred from the northwest and southwest provinces to the southeast provinces and Beijing-Tianjin-Hebei region; 2) the flow with the highest flow rationality index is Inner Mongolia-to-Hebei (29.8), while the lowest one is Shanxi-to-Hubei (−102.5); 3) the node with the highest node rationality index is Hebei (32.0), while the lowest one is Shanxi (−104.7). By quantifying the impacts of electricity transmission on provincial and national water stress, this study aims to provide guidance for national virtual water strategy by electricity transmission to mitigate national water scarcity. • Virtual water transfers embodied in China's interprovincial electricity trade is calculated in 2014. • A rationality assessment model is proposed to evaluate whether the water transfers positively or negatively impacts overall water scarcity for a region. • Based rationality assessment model, the rationality index for flows and provinces is analyzed. [ABSTRACT FROM AUTHOR]

Expansion of electric grid has induced increasing stress on regional water resources. Yet, few insights have been gained into the network dynamics of virtual water flows embodied in interprovincial electricity transmission. Here, we calculated the interprovincial transfer of virtual water and virtual scarce water associated with electricity transmissions in China during 2005–2014, considering both thermal power and renewable energies. To track the network dynamics of virtual water, we identified control and dependence relationships between provinces related to exchanging virtual water, using network control analysis. We found that the magnitudes of virtual water and virtual scarce water transferred from western provinces to the rest of China have increased five-fold between 2005 and 2014. The transfers of virtual water exacerbated the water scarcity in northwestern provinces over time, while the transfers between southwestern provinces mitigated the local water scarcity. Southwestern provinces have strong control over the Yangtze River Delta region due to the supply of virtual water in hydroelectricity transmission inbetween. In contrast, the interdependence among northwestern provinces has been strengthened over time. Gansu, Xinjiang and Inner Mongolia have become more dominant in controlling the virtual water appropriated by Beijing–Tianjin–Hebei region and Shandong over this period. We suggest that the dynamics of electricity-induced virtual water transfers across regions be regularly tracked to address water scarcity during constructing power plants and adjusting electricity dispatches. • Virtual water in electricity transmission has increased five-fold between 2005 and 2014. • Thermal power has a greater impact on virtual scarce water than virtual water. • Expansion of renewable energies in power system mitigated water scarcity in China. • The flow of virtual water has been controlled by more regions over time. [ABSTRACT FROM AUTHOR]