LOW-CARBON ENERGY MODERNIZATION OF CRITICAL INFRASTRUCTURE IN THE DIGITAL ECONOMY: TRANSITIONING WATER UTILITIES TO INDUSTRY 4.0/5.0 IN WARTIME

The article substantiates strategic priorities, organizational-economic, and financial mechanisms for the low-carbon energy modernization of water utilities as critical infrastructure assets in Ukraine. It is demonstrated that, under wartime conditions, power grid capacity shortages, and persistent blackout risks, improving internal energy efficiency and enhancing utility autonomy are key drivers of national security, community viability, and achieving national decarbonization targets. Based on an analysis of cost structures and load profiles, it is identified that the primary share of energy consumption in water utilities is concentrated at the water intake and distribution stages, justifying prioritizing investment in the energy modernization of these operational steps. Key technical-economic inefficiencies and energy-related economic risks facing water utilities during wartime are systematized. It is identified that legacy Industry 3.0 operational approaches (relying on mechanical valve throttling) lead to excessive electricity expenditures, whereas the deployment of Industry 4.0 and 5.0 digital tools (VSDs, SCADA systems, and IoT sensors) yields a 15–30% reduction in operating costs. A roadmap for deploying solar photovoltaic power plants at water utility sites integrated into internal energy management systems is proposed. Relying exclusively on municipal budgets for funding such projects is shown to be impractical; instead, financial models are formulated that combine municipal co-financing (10–15% of CAPEX), green loans from international financial institutions (EBRD, EIB, NEFCO), non-repayable grants, and PPAs with private investors. A conceptual framework for the organizational-economic support mechanism for energy modernization is developed to optimize capital costs and build green resilience within the municipal sector. It is proven that decarbonization, energy security, and operational resilience of water utilities represent mutually reinforcing objectives. The practical value of the findings lies in establishing a decision-support system for municipalities. Future research may focus on leveraging Industry 5.0 tools, artificial intelligence, and industrial energy storage systems to further support the energy modernization of water utilities.