Optimization of Fuel Contract Management and Maintenance Scheduling for Thermal Plants in Hydro-based Power Systems

Abstract

The objective of this work is to present a decision support system to determine the optimal dispatch strategy of thermal power plants taking into account the particular specifications of fuel supply agreements, such as take-or-pay and make-up clauses. Opportunities for energy purchase and selling at the spot market as well as a detailed modeling of the power plant (maintenance cycles, influence of temperature, etc) are also considered in the optimization. In an integrated way, the model also determines the plants' optimal schedule for maintenance. Since decisions in one stage impact the future stages, the problem is time-coupled in a multi-stage framework. Moreover, the main driver for the decision-making is the energy spot price, which is unknown in the future and is modeled here through scenarios. Therefore, the optimal dispatch strategy is a decision under uncertainty problem, where at each stage the objective is to determine the optimal operation strategy that maximizes the total revenues taking into account constraints and characteristics of the fuel supply contract. The methodology applied is the Stochastic Dual Dynamic Programming (SDDP). Examples and case studies will be shown with the Brazilian system.