Catchment-level water stress risk of coal power transition in China under 2℃/1.5℃ targets

Abstract

Coal power production is the second largest source of water demand in China. However, as coal power would undergo significant changes under ambitious climate goals (2℃ or 1.5℃), it’s not clear how the low-carbon transition of the power sector made at the provincial level would affect the catchment-level water resources in the future. With a power system model (MESEIC) and a unit-level coal-fired power unit dataset, this study explores different power sector transition pathways from 2020 to 2050, and maps out the catchment-level water stress risk of China’s coal power with Monte Carlo method. Results show that the future power supply mix varies much under the shared socio-economic pathways (SSPs) and carbon emission targets. Without carbon emission targets, coal power would continue to dominate the power supply mix advantage and would cause severe risk of water stress. Under SSP1-5, the national water withdrawal from coal power in 2050 would be 12.2–176.2 billion m3 under the reference scenario, but would decline to 10.7–59.2 billion m3 with 2℃ target and 0.11–35.5 billion m3 with 1.5℃ target. Compared with the 2℃ target, the catchment-level water stress risk generated by coal-fired power plants in north China would be significantly reduced under the stricter target of 1.5℃. However, the benefits would be reduced under SSP5 because of the application of carbon capture and storage. This study reveals the strong synergies between reducing carbon emissions and alleviating water stress risk in China’s power sector, but regional risk should be noted while achieving the carbon reduction targets.