On the hydropower short-term scheduling of large basins, considering nonlinear programming, stochastic inflows and heavy ecological restrictions

Large hydro basins are difficult to optimally operate, due to extended water travel times, numerous tributaries to the same reservoir, uncertainties in the water inflows and different characteristics and efficiencies of the hydro plants. Also, optimal management must consider ecological restrictions, guarantying legal and social requirements. This paper proposes an advanced optimization tool, improving economic profits while meeting European and local regulations. Nonlinear relationships between efficiency, height and stored water are represented through piecewise linear functions, without requiring integer variables. Uncertainties in the water inflow and large travel times are considered by using stochastic scenarios. The Guadalquivir Basin, in southern Spain, with 18 reservoirs, a minimum of 50 h between head and mouth of the considered section and strong flow restrictions is analyzed in the study. Results show the robustness of the model and the validity of statistical studies for short-term studies, given a large chain of reservoirs, dry circumstances and strong operation constraints.