Citation: Postolov, B.; Hinov, N.; Iliev, A.; Dimitrov, D. Short-Term Hydro-Thermal-Solar Scheduling with CCGT Based on Self-Adaptive Genetic Algorithm. Energies 2022, 15, 5989. https://doi.org/10.3390/ en15165989 Academic Editor: Javier Contreras Received: 20 July 2022 Accepted: 14 August 2022 Published: 18 August 2022 Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affil- iations. Copyright: © 2022 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). energies Article Short-Term Hydro-Thermal-Solar Scheduling with CCGT Based on Self-Adaptive Genetic Algorithm Borche Postolov 1, *, Nikolay Hinov 2, * , Atanas Iliev 1 and Dimitar Dimitrov 1 1 Faculty of Electrical Engineering and Information Technologies, Ss. Cyril and Methodius University, Ruger Boshkovikj 18, P.O. Box 574 Skopje, North Macedonia 2 Faculty of Electronic Engineering and Technologies, Technical University of Sofia, 8 Kl. Ohridski Blvd, 1000 Sofia, Bulgaria * Correspondence: borce.postolov@hotmail.com (B.P.); hinov@tu-sofia.bg (N.H.) Abstract: This paper presents a new metaheuristic approach based on a self-adaptive genetic al- gorithm (SAGA) for solving the short-term hydro-thermal-solar scheduling with combined-cycle (CCGT) units. First of all, the proposed approach is applied to a test system with different character- istics, considering the valve-point effect. The simulation results obtained from the new SAGA are compared with the results obtained from some other metaheuristic methods, such as AIS, DE, and EP to reveal the validity and verify the feasibility of the proposed approach. The test results show that the proposed metaheuristic approach proves the effectiveness and superiority of the SAGA algorithm for solving the short-term hydro-thermal-solar scheduling (SHTSS) problem. Keywords: hydrothermal scheduling; genetic algorithm; self-adaptive penalty; Laplace crossover; MPTM mutation 1. Introduction In the recent period, the electric power demand has increased and fossil fuel prices have risen, which has led to growing the world energy crisis. Therefore, the world has tended to reduce the use of TPP by using renewable energy sources to reduce the emissions and harmful gases that are released from TPP. These harmful gases harm the environment, and this leads to an increase in the temperature of the planet, which causes global warming. Accordingly, the European Union has introduced stricter directives, which provide for the decommitment of TPP, and a gradual increase in the renewable penetrations in the system [1–3]. Therefore, the incorporation of the short-term hydrothermal generation scheduling (STHS) problem and new renewable energy integration has great importance in the power system operation [4]. The STHS problem is one of the most important optimization prob- lems in power system planning. The primary goal of the STHS problem is to determine the optimal power-generation schedule of the TPP and HPP to minimize the total operation cost of the system. On other hand, the total operating costs and flexibility of the TPP’s oper- ation can be favorably influenced by committing combined cycle gas turbines (CCGT) into the system and the appropriate decommitment of existing conventional TPPs, especially in the transition period, which has already begun. However, in SHTSS, one of the basic features of solar power plants (SPP) is the extreme variability and unpredictability of the output power, primarily due to the dependence on weather conditions [5]. These two attributes are especially evident in modern power systems, in which solar power plants have an increasing penetration. In addition to this, modern PV modules use bifacial technology [5], so their orientation significantly affects the output power of the solar power plant and, thus, all the parameters of the system (including costs). According to what has been said so far, it can be said that this paper deals with the impact of the orientation of Energies 2022, 15, 5989. https://doi.org/10.3390/en15165989 https://www.mdpi.com/journal/energies