Reservoir operation considering carbon benefits of drawdown zone emissions

• Published in: Journal of hydrology (Amsterdam) 2025-03, Vol.649, Article 132442
• Main Authors: Yang, Yichen, Liu, Pan, Li, Shiqiong, Wang, Yibo, Liu, Yang
• Format: Article
• Language: English
• Subjects: Carbon emissions; Multi-objective optimization; Operation rule curves; Reservoir drawdown zone
• ISSN: 0022-1694
• DOI: 10.1016/j.jhydrol.2024.132442

•The carbon emissions were calculated considering area fluctuation and CO2 fluxes.•The carbon emissions competed with hydropower generation.•Preferred operation rule curves improved both carbon and economic benefits. Hydropower was considered a traditional clean energy compared to thermal power. However, the carbon emissions from the drawdown zone could reduce the carbon benefits, which were seldom considered in reservoir operation. This study aimed to balance the carbon emissions of the drawdown zone and the hydropower benefits through reservoir operation. Firstly, the carbon emissions of the drawdown zone were estimated by considering the area and the fluxes of the drained, retreated, and inundated areas, respectively. Secondly, the multi-objective optimizing operation model was built by considering the annual average carbon emissions (AACE), annual average hydropower generation (AAHG), annual average water supply (AAWS), and suitable river length for fish spawning (SRL). Finally, the preferred operation rule curves (ORCs) that improved all the objectives were derived. The methodology was applied to the Danjiangkou reservoir, in China. Results were as follows: (1) The AACE was consistent with AAWS, competitive with AAHG and SRL. (2) Compared with the conventional ORCs, the preferred ORCs reduced AACE by 6.46%, and increased AAHG by 2.36%, AAWS by 0.87%, and SRL by 0.60%. (3) Higher key points after the flood season indicated less carbon emissions. The proposed methodology could provide technical support to improve carbon benefits by reservoir operation.