Techno-economical method for the capacity sizing of a small hydropower plant

► A method for the capacity sizing of a small hydropower plant was developed. ► The model was developed on the basis of the flow duration curve of the site. ► Seven techno-economical parameters were considered in the analysis. ► The influence of the design operating conditions on the parameters was analysed. ► The method allowed a proper choice of the optimal design operating conditions. This paper presents a method for the capacity sizing of a small hydropower plant on the basis of techno-economical analyses of the flow duration curve. Seven technical and economical parameters were considered: the turbine type, the turbine dimensions, the annual energy production, the maximum installation height to avoid cavitation inception, the machine cost, the Net Present Value (NPV) and the Internal Rate of Return (IRR). A proper model was proposed to study the effects of the design operating conditions on these parameters. The model, applied to the flow duration curve, allowed to analyse the feasibility, the profitability and the performance of the plant in the available flowing range of the site. To verify the effectiveness of the proposed method, three sites having different flow duration curves were analysed.