Composite surge tanks to boost hydropower flexibility

Abstract

Hydropower is key for achieving sustainable decarbonization by offering critical flexibility and large-scale energy storage to integrate variable generations. In conventional settings, it uses conventional surge tanks to damp hydraulic transients. However, this has adaptability limitations that need new surge tank design considerations. In this study a novel composite surge tank has used to enhance transient management, stability, and flexibility of hydropower plants with long headrace tunnels. The study considered a 1300 MW PSH plant as case study. Transient analysis for selected load change scenarios for open, closed, and composite surge tank has analyzed and compared. The composite surge tank design demonstrated excellent performance of governing, mass oscillation damping, power ramping, and minimized pressure fluctuations that are important parameters for balancing and large-scale energy storage role of hydropower. It damped the 40 m water hammer and mass oscillation surges of OST and CST into 8 m in front of the turbine. This highlights the surge tank's potential to boost flexible operation. This design not only enhances upgrading and expansion of existing hydropower infrastructures but also encourages new developments to ensure reliable energy transition. Authors recommend the implementation of this surge tank design in new hydropower developments.