Water scarcity risks mitigated or aggravated by the inter-regional electricity transmission across China

Traditionally, around 34–38% of China's population resides in places experiencing high water scarcity for at least one month a year. However, the risk of water scarcity may be further exacerbated by inter-regional electricity transmission, due to the mismatch between the electricity-receiving population living in water-abundant areas and the water scarcity experienced in the electricity-exporting region. Using detailed thermal/hydro- power plants data and water scarcity index at the water basin scale, this study systematically quantified this additional water scarcity risk across China. The affected population, i.e. those living in basins under lower water scarcity but needing electricity generated in basins with higher water scarcity, was estimated to be 134 million, or 10% of the total population in China. Among this, over 60 million people were considered as highly-affected population (i.e. people who live in no/low stress basins rely on electricity generated in severe/extreme scarcity basins), the majority of whom lived in Southern China. This leads to a 12% increase in water-stressed population if the proposed transmission projects were implemented. On the other hand, more people, i.e., 285 million, would benefit from the inter-regional electricity transmissions. They relied on the electricity generated from basins under lower water scarcity. It is found that intra-grid's thermal electricity transmission was less effective in mitigating the water scarcity than the hydroelectricity. It determined that the southern part of China faced worse environmental performance in coordinating its water endowment with the electricity generation because of its use of electricity from water stressed basins rather than from the water sufficient basins.