Heuristic-Exact Hybrid Approach to the Thermal Unit Commitment Problem

Brazil's power matrix is marked by a high share of renewable sources, especially hydropower. However, climate variability poses risks to energy security, requiring complementary use of thermal plants, which have higher operating costs and environmental impacts. In recent years, thermal generation has gained importance in Brazil, increasing the need for efficient planning of its operation. In this context, the Thermal Unit Commitment (TUC) problem arises as a complex combinatorial optimization challenge aimed at determining the set of thermal units to be operated at each time period while satisfying technical constraints and minimizing the total generation cost. This paper proposes an approach based on priority lists combined with the Branch and Bound method to reduce the search space and accelerate the identification of high-quality feasible solutions. The methodology is tested on two different systems and proves effective in reducing computational effort without compromising solution quality.