The climate crisis requires significant changes across society. While reducing emissions remains crucial, the intermittent nature of renewables like wind and solar poses challenges. Innovative energy storage solutions are needed to enhance the reliability, stability, and accessibility of renewable energy. The adoption of Battery Energy Storage Systems (BESS) is decisive in addressing the criticalities of transitioning to a sustainable energy system more rapidly. This thesis examines the regulatory, technological, and economic context that influences the diffusion of Battery Energy Storage Systems (BESS), with a focus on the European and Italian situations. It covers the initial developments of energy storage technologies, including mechanical, chemical, electrochemical, and electrical storage.