A Multidimensional Analysis of Existing Limitations for TSO-DSO Coordination

The growing penetration of distributed energy resources (DERs) has motivated a large body of literature on transmission system operator (TSO) and distribution system operator (DSO) coordination. Yet despite this research activity, pilot projects and commercial deployments remain much more limited. Existing reviews classify coordination schemes by architecture or market design, but provide limited insight into the practical barriers affecting deployment readiness. This paper introduces a multidimensional scoring framework that evaluates TSO-DSO coordination approaches across five dimensions: modeling assumptions, operational dynamics, validation at scale, communication requirements, and regulatory constraints. The framework is applied to 47 selected studies, divided into pilot and non-pilot works. Our analysis shows that pilot and non‑pilot studies are similarly developed in modeling and operation, but diverge on validation, communication, and regulatory alignment. These results suggest that the primary bottleneck for deployment is not necessarily algorithmic complexity, but rather the lack of integration of non-technical and systemic constraints. The proposed framework highlights key research gaps and proposes directions for developing coordination methods better suited to commercial deployments.