Digital Twin Modelling for a Renewable Energy Community: A Case Study of the Culatra Island’s Smart Grid

Abstract

This study develops and tests a Digital Twin (DT) of the Culatra Island’s distribution grid to enable the evaluation of demand side management strategies, in the scope of Renewable Energy Communities. Built in MATLAB/Simulink and structured across five functional layers, the DT integrates real-world data from five photovoltaic (PV) production units, monitored and fixed electrical loads, and realistic network parameters derived from the island’s infrastructure. Three steady-state test scenarios were simulated to assess voltage stability, and power flow under: (1) baseline grid operation without PV generation, (2) distributed PV integration under normal load conditions, and (3) high-demand operation near generation-load equilibrium. Results show that PV integration improves voltage regulation and reduces losses through localized energy injection and bidirectional power flow. However, under peak load conditions, the system exhibits significant undervoltage, revealing the need for advanced control strategies and infrastructure reinforcement. Overall, the DT proves to be an effective analytical and decision-support tool for optimising distributed energy systems. This work provides a replicable application-oriented framework for data-driven planning in emerging Renewable Energy Communities and supports Culatra Island’s transition toward full energy self-sufficiency. Unlike prior studies that report generalized benefits of PV integration, this work explicitly identifies voltage instability thresholds under high-demand conditions in a real REC configuration, providing actionable insight into when passive operation becomes insufficient.