Secondary development and utilization of hydropower under carbon neutrality goal

Abstract

[Objective] Under the “dual carbon” goals and increasingly stringent ecological constraints, tapping the potential of existing hydropower stations and enhancing renewable energy integration capacity are crucial for building a new power system. A coordinated planning method for secondary hydropower development and multi-energy complementarity suitable for river basins with mature hydropower development is proposed.[Methods] Taking the Danjiangkou-Wangfuzhou cascade reservoirs in the Han River as the study object, a short-term optimal dispatch model was first constructed with dual objective of maximizing cascade power generation and generation benefits, incorporating downstream ecological flow constraints. After the feasible domain for hydropower capacity expansion was determined through life-cycle economic evaluation, a regional hydro-photovoltaic(PV) complementary coordinated operation model was further established with the objective of maximizing renewable energy integration and minimizing the variance of the system's residual load.[Results] The Danjiangkou Hydropower Station was found to possess the technical potential for capacity expansion to 1500 MW. Life-cycle economic comparison identified the 1200 MW expansion scheme as the optimal solution. Implementation of a 10~20 cm over-storage operation strategy for the Wangfuzhou Reservoir during the non-flood season effectively compensated for the peak shaving capacity loss caused by fixed ecological flow release. When complemented by an installed photovoltaic capacity of 750 MW, the system's total annual power generation reached 4 billion kWh, representing a 10.7% increase compared to the baseline scheme. Furthermore, the variance of the system's residual load was smaller, and the power deficit rate decreased from 2.48% to 2.43%.[Conclusion] The proposed system solution of “expansion potential assessment-ecological and peak-shaving coordination-multi-energy complementarity optimization” can provide a theoretical basis and practical reference for basin-level secondary hydropower development and capacity configuration of hydro-PV complementary systems. The configuration of Danjiangkou expansion to 1200 MW coupled with 750 MW PV is the optimal scheme, demonstrating significant advantages in improving power generation benefits and renewable energy integration.

Keywords

hydropower secondary development / hydro-photovoltaic complementation / multi energy complementary / differentiated targets for cascade hydropower stations / ecological flow operation / cascade reservoir operation / economic analysis / comprehensive evaluation