However, the dispatch of solar and wind renewable energy has increased the need to enhance the flexibility of power system management and operation due to the inherent uncertainty and variability of these sources. To efficiently harness renewable energy, various technologies in generation, transmission, and demand have been deployed to address operations focused on resolving events of uncertainty and variability. This work reviews the technological solutions being developed for flexible operation in generation, storage, transmission, and demand. Furthermore, it examines the different flexibility options within the system and how they influence system operation and planning, highlighting the importance of flexible operation to achieve a sustainable energy transition.