Tracking flows and network dynamics of virtual water in electricity transmission across China

Abstract

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.