Assessment of energy availability in hydro systems under different operational policies

This paper is concerned with the assessment of energy availability in hydro systems under different operational policies. Optimization and simulation models representing the detail operating characteristics of hydro plants, including the consideration of the influence of forebay and tailrace elevation on hydro conversion efficiency were considered. The assessment of energy availability was based on the calculation of duration curves for hydro generation and the identification of firm energy, guaranteed energy, and secondary energy, as well as average and standard deviation values of energy availability. Various operational policies have been evaluated to determine their influence on the energy availability of the system. Twenty of the most important hydro plants from the Brazilian system were used in the numerical tests, with case studies performed to highlight the relation between energy availability and operational policies. The economic profiting of secondary energy was also addressed.