Analysis of water-energy nexus considering the net zero-carbon transformation of power sector in Southern China

In China, the carbon peak and neutrality targets proposed in 2020 will not only reduce carbon emissions, but also improve the sustainable development level of the whole society. As a major CO₂ emitter and water-energy consumer in China, the long-term sustainable development of power sector has become an energy structure transition and water resource conservation issue considering China’s "30–60" CO₂ goals. The development of renewable energy, such as hydropower, has been important to the long-term sustainable development of power industry. However, China's current water resources policy did not consider the water consumption by hydropower in waterways, and previous research has also neglected the drawback of hydropower in the perspective of water consumption, exaggerating the advantages of hydropower in sustainable development. Therefore, to achieve long-term sustainable development of power sector and improve the current water resources policy in China, this paper initially established a long-term multi-regional water-energy optimization model for power sector under "30–60" goals, considering the interaction of policies about renewable energy promotion, instream water conservation and CO₂ emission reduction; and analysed the influence of current and enhanced water policies on power sector by taking the Southern China, which is rich in hydropower, as a case. Based on these results, this paper has provided an optimal schedule for the power sector in Southern China until 2060 from the perspectives of power generation, power trading, water consumption, and water-energy nexus. What’s more, compared with the enhanced water policy that considering the water consumption in rivers, the current water policy will neglect 92.62 hundred million m³ water every year in Southern China from 2021 to 2060. Therefore, this paper revealed that water consumed in rivers by hydropower should be considered in Southern China’s water policy to achieve the long-term sustainable development in the power sector.