Co-optimization in the operation of hydroelectric and solar generation in the province of San Juan: Methodology

This paper presents a mathematical non-linear programming model applied to the operational optimization of a regional hydroelectric power production system with multiple reservoirs that also includes renewable (solar) generation.The regional system is linked to a larger system (national interconnected system) through one or more tie-power lines. The hourly nodal market prices at the buses ends of the tie-lines are used to value power exchanges (exports or imports). These prices (or marginal costs) are parameters for the optimization procedure and their estimation is based on the mid-term operational planning published by the national system operator.The model considers cascaded hydro systems with head-sensitive plants and a DC power flow to represents the transmission network and its constraints. Optimal hourly scheduling of each plant is obtained within a medium-short term horizon ranging from one day up to eight weeks.The model is applied to the interconnected system of the San Juan province, Argentina, including the cascade hydroelectric exploitation on San Juan river composed by three reservoirs and four hydroelectric plants. The results show the optimal scheduling to maximize the revenues of the generation company that operates hydroelectric plants. The impact of non-linear production functions of hydroelectric power plants on the results are analyzed by comparison with a simplified linear modeling.