Explains what a digital twin of the electricity grid actually is — not just a simulation model, but a virtual representation that stays continuously linked to the physical asset through live data and supports decisions across its life cycle (ISO/IEC 30173). Frames the policy context (EU 'Digitalising the energy system' action plan, ENTSO-E RDI Roadmap 2024–2034) and then argues that there will be no single monolithic 'twin of the grid'; instead Europe needs federation. Walks through three federation patterns — horizontal (across departments of a single operator), vertical (asset → substation → whole grid), and distributed modular (across TSOs, DSOs and member states, as in the TwinEU project and the OneNet Connector).
Covers core use cases (operational control and pattern recognition, resilient planning, prosumer and flexibility services, market operations) and uses the 28 April 2025 Iberian blackout to illustrate where twins would have helped.
Closes with the practical agenda: data standards (CIM, SAREF, IEC 61850/61970), 'connect, don't collect', breaking data silos, and a migration path from single use cases to interoperable, federated twins.
