## 6 Conclusions and Outlook
In addition, the digital twin creates new economic opportunities by supporting the development of flexibility markets, stimulating innovation in energy software, and offering a competitive export platform for Europe's digital energy technologies. The broader significance of the grid twin is not just operational, but systemic. It exemplifies the kind of transnational, cross-sectoral digital infrastructure that will underpin Europe's future energy and climate policy. As it matures, the grid twin could interconnect with other digital twins in climate, urban planning, and mobility, thereby laying the foundation for truly integrated modeling of Europe's complex socio-technical systems. This positions Europe not only as a pioneer in digitalizing its own energy transition, but as a global leader in the governance and deployment of energy system digital twins. For European citizens and businesses, the digital twin's presence may be invisible, but its effects will be palpable. It will enable faster integration of clean energy, more reliable power supply, quicker grid connections, and more cost-effective investment decisions. It will also reduce Europe's exposure to fossil fuel volatility and support the creation of a digitally enabled energy workforce. Importantly, the digital twin encapsulates the EU's ethos: leveraging shared knowledge and technical cooperation to build public goods that transcend national borders. To enhance the accessibility of key insights, Table 4 provides a conceptual mapping of the main regulatory, technological, and economic barriers identified in this review, alongside the proposed policy and technical solutions. This conceptual mapping aims to support readers in navigating the complex interdependencies shaping the development of a federated EU-wide grid digital twin. Currently, the European grid digital twin is moving from aspiration to reality. Policy frameworks have been defined, pilot projects are demonstrating feasibility, and institutional momentum is building. The years ahead will determine how effectively this vision is scaled, regulated, and integrated. Success will depend not only on technical excellence but on continued collaboration between regulators, network operators, industry, and researchers. If that collaboration continues and expands, the digital twin will become a foundational layer of Europe's future electricity infrastructure; a living, adaptive digital system that enhances the physical grid's performance, resilience, and sustainability. This \begin{table}
\begin{tabular}{c c c} \hline
**Dimension** & **Identified Barrier** & **Proposed Solution** \\ \hline Regulatory & Fragmented data governance & CEEDS, GDPR alignment, and Data Act \\ \hline Regulatory & Lack of interoperability mandates & Binding Implementing Acts and updated \\  & & grid codes \\ \hline Technological & System interoperability and data integration & Common Information Model (CIM) and open APIs \\ \hline Technological & ICT infrastructure and cybersecurity gaps & Cloud–edge hybrid architecture and \\  & & NIS2 compliance \\ \hline Economic & CAPEX–OPEX misalignment & TOTEX models and innovation allowances \\ \hline Economic & No cross-border cost allocation mechanism & Harmonized EU-wide cost-sharing frameworks \\ \hline \end{tabular}
\end{table} 
Table 4: Conceptual mapping of regulatory, technological, and economic barriers to proposed solutions for the EU grid digital twin. transformation, grounded in a combination of political will, technological innovation, and collective governance, stands to deliver profound long-term benefits for Europe's energy system and society. Conceptualization, B.N.J. ; methodology, Z.G.M. ; validation, Z.G.M. and B.N.J. ; formal analysis, Z.G.M. and B.N.J. ; investigation, Z.G.M. and B.N.J. ; resources, B.N.J. ; data curation, Z.G.M. ; writing--original draft preparation, B.N.J. ; writing--review and editing, Z.G.M. and B.N.J. ; visualization, B.N.J. All authors have read and agreed to the published version of the manuscript. This research received no external funding.