Guest Editorial Special Section on Real-World Challenges of TSO-DSO Coordination

The papers in this special section focus on the coordination of transmission system operators (TSO)-distributed system operators (DSO). Policy directives and technological innovations have fostered the emergence of a hierarchical market structure, which consists of centralized and decentralized markets. It is envisioned that energy resources will be free to participate in all market structures at the same time to extract the maximum value to the grid and monetize their services. Under this market architecture, grid operators can procure energy services from assets connected both at transmission and at distribution level in a coordinated way. This structure requires an efficient network management and optimization, also for the benefit of Distributed Energy Resources (DERs) in the transition to a decarbonized economy. The same pool of resources may be used by TSOs and DSOs, so actions by both can mutually affect each other.