Resilience of hydropower plants to flow variation through the concept of flow elasticity of power: Theoretical development

Abstract Fluctuation in hydro-electricity production is primarily attributed to natural and human-induced flow variations. Reduced electricity generation because of unavailability of flow inflicts significant upward pressure on the sources and prices. Despite studies on the impact of externalities on river flow variation, there is a distinct research gap on the responsiveness of hydropower plants to change in flow. This study has introduced a novel concept of flow elasticity of power ( e ) to assess the resilience of hydropower projects to flow variation. The theoretical aspect has been established for run-of-river (ROR) and storage-type (ST) cases separately and validated at two projects, one of each type, located in the Budhigandaki Basin in central Nepal. Responsiveness of hydro-projects to the topographical parameters are also dealt with here. For ROR systems, wide-ranging values of e indicate varying levels of resilience to power generation and loss of resources. For ST projects, the response differs according to emptying, filling and ROR-equivalent phases. Furthermore, strong topographical implications on power production and its elasticity are evident. This concept of e sets out a significant research contribution in the hydropower sector and demonstrates its possibility of direct application in projects in ‘priori’ as well as ‘posteriori’ while planning/designing and updating stages, respectively. The e coefficient scientifically informs the planners and developers on the sensitivity of the powerplants to hydrological variations and topography ultimately benefitting the existing global challenge to minimize the loss of precious resources for sustainable hydropower development.