STRUCTURAL AND FUNCTIONAL MODEL OF "BIOMETHANE" TRANSFORMATION OF THE ENERGY SECTOR OF UKRAINE

The aim of the article is to theoretically substantiate and develop a comprehensive structural and functional model of biomethane transformation of the energy sector of Ukraine. The research is aimed at overcoming the existing fragmentation of scientific approaches by forming a holistic concept that ensures systematicity, sectoral coherence and adaptability of transformation processes within the framework of the global decarbonization strategy. Methodology. The study is based on a systems approach and tools of structural-functional analysis, which allowed interpreting the energy transformation as a complex socio-technical-economic system. To visualize synergistic effects, conceptual and spatial modeling methods were used, which provide a reflection of the interaction between key subsystems. The methodological basis was expanded by a comparative analysis of traditional and modern energy models, taking into account the transition to renewable energy sources. Special attention was paid to nonlinear relationships between subsystems, which allowed adapting the logic of the inter-sectoral model "input-output" by W. Leontief to explain the dynamic structural exchange of resources, capital and knowledge within the energy cluster. Results. A three-vector structural-functional model of biomethane transformation has been developed, which is based on the hierarchical interaction of institutional (regulatory "rules of the game"), economic (motivational and financial levers) and technological (production and infrastructure contour) components. It has been proven that the efficiency of transformation is nonlinear: any asymmetry in the development of subsystems – for example, technological renewal without institutional stability or financial incentives – levels the systemic result. It has been established that the critical condition for maximizing the integral effect is the spatial and temporal synchronization of the above factors, which allows for the formation of a sustainable energy ecosystem. At the same time, it is shown that the introduction of innovative technologies for cleaning and enriching biogas to the level of biomethane, as well as its integration into the existing gas transportation infrastructure, provide a multiplicative effect, which is manifested in increasing energy efficiency, diversifying energy sources and stimulating the development of related industries, primarily the agricultural sector of the economy. Practical implications. The proposed model forms a reliable conceptual basis for the development of effective state policies, investment programs and strategies for the post-war restoration of the energy sector of Ukraine. The practical application of the model will allow optimizing the regulatory environment, reducing investment risks and increasing the predictability of the functioning of the biomethane market. An important aspect is the possibility of using the model as a decision-making support tool for the development of public-private partnerships, which will contribute to the activation of investment activities and the acceleration of the implementation of innovative technologies. Value/Originality. The originality of the research lies in the departure from the fragmentary study of the «biomethane» transformation and the formation of a single concept that combines institutional, economic and technological aspects within a holistic model. The proposed approach expands the theoretical foundations of the study of energy transformations, substantiating them as a process of forming a new system of sustainable and renewable value creation. This allows us to consider biomethane not only as an alternative energy source, but also as a strategic resource for the structural modernization of the Ukrainian economy in the face of global climate challenges.