Unveiling long-term indirect socio-economic and environmental effects of large-scale hydropower project.

Large hydropower projects (LHPs) can generate significant direct socio-economic and environmental (SEE) impacts, which may radiate and accumulate gradually through the supply/consumption chains over different development periods. Therefore, a dynamic hydroengineering equilibrium analysis (DHEA) model is developed in this study to comprehensively quantify the cumulative indirect SEE impacts of LHPs during their construction and long-term operation period. The proposed DHEA model will be applied initially to the Baihetan hydropower project (BHT), the second-largest LHP in the world, which recently commenced operation. The results indicate that the construction of BHT generates approximately 0.81 billion yuan in GDP annually for the YREB region through supply/consumption chains. Starting in 2023, the operation of BHT will have a long-term positive indirect impact on the YREB region, with significant cumulative effects over time. It is expected that by 2033, the cumulative contribution of BHT's construction and operation to the YREB's GDP will exceed the initial government investment in BHT (220 billion yuan). Additionally, during the operation periods, BHT will significantly reduce the YREB's energy input/consumption and trade/local embedded carbon emissions through supply/consumption chains. The developed DHEA approach is expected to highlight the multi-dimensional, multi-phase, and multi-sectoral indirect impacts of LHPs and contribute to evaluating the SEE effects of other LHPs worldwide.