The paper explores the prospects of implementing energy storage systems to scale the development of renewable energy in Ukraine, focusing on the electricity sector. The integration of energy storage systems and renewable energy technologies is considered through the lens of energy security indicators that are most relevant to the context of the study (energy import dependence, energy availability, energy system flexibility, energy system interconnectivity, energy system sustainability, and energy policy and regulation). Within each indicator, the challenges to achieving Ukraine’s energy security and the ways to mitigate them by integrating renewable energy with energy storage systems are analysed. The results obtained can be used as a scientific basis for developing strategies to strengthen energy security and the post-war reconstruction of Ukraine’s energy sector based on sustainable and resilient energy solutions.