Abstract: The research investigates the use of fuzzy logic models to make informed

investment decisions on material assets at thermal power plants (TPPs) in Ukraine. Given the complexity and dynamic nature of the countryʼs energy system, as well as the necessity to replace outdated equipment, investment planning for capital repairs and modernization has become an essential component of management operations. In this regard, traditional planning methods are not always effective due to the presence of multiple unpredictable or ambiguous aspects influencing decision-making, such as economic fluctuations, legislative changes, environmental restrictions, and technology developments.One option to tackling this issue is to use fuzzy logic models, which allow for the processing of unclear and partial information that arises during times of instability. Fuzzy logic allows

for the assessment of risks, costs, and benefits of investment decisions when precise data is unavailable or inadequate. This strategy enables flexible management of capital repairs, modernization, and equipment replacement while accounting for unanticipated changes in the external environment.

The article also examines specific features of TPP operation in Ukraine, specifically the role of movable generation and its impact on the energy supply-demand balance. TPPsʼability to quickly modify output makes their participation in regulating the energy grid critical for ensuring the energy systemʼs stability. The application of fuzzy logic models in investment planning not only reduces risk levels but also optimizes modernization costs for TPPs, which is an essential step in ensuring stable energy supply in Ukraine. The recommendations developed can be used to improve the management of energy enterprises and make more informed decisions in the field of capital repairs