Proceedings of the International scientific and practical conference ―Multidisciplinary approaches in science, technology and culture‖ (September 5-7, 2025) / Publisher website: www.naukainfo.com. – Oxford, United Kingdom, 2025. - 124 p.

112 POWER ENGINEERING AND POWER MACHINE ENGINEERING UDC 620.91:621.311:681.5 Matushkin Dmytro PhD (Engin.) Zgurovets Oleksandr PhD (Engin.), senior researcher General Energy Institute of NAS of Ukraine Kyiv, Ukraine POWER BACKUP AND RENEWABLE ENERGY PRIORITIZATION SCENARIOS Abstract. Hybrid energy systems combining renewable sources, battery energy storage, and backup generators ensure uninterrupted power supply through real-time source prioritization and scenario-based energy management systems control. This work aims to synthesize a multi-layer reserve logic and show how a decision hierarchy reduces fuel consumption and equipment wear while increasing the share of renewables. The proposed sequence is: cover the load first with solar and wind; charge the Battery Energy Storage System when surplus is available; compensate deficits using the BESS; automatically start the diesel generator at a state of charge of 20–25%; use the external grid as the last resort or for economically justified charging. The baseline operating scenarios are distinguished as follows: renewables-dominant; night/calm conditions with Battery Energy Storage System dominance; peak periods with joint operation of sources; and emergency islanded operation for critical loads. It