Jóni Buchinho Santos

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.

Digital Twin (DT) technologies are increasingly central to the decarbonisation of energy systems, enabling close coupling between physical infrastructures and continuously updated virtual models. Through real-time data exchange, simulation, and predictive analytics, DTs support advanced monitoring, optimisation, and control of distributed renewable resources. This paper reviews the evolution of DT applications in the energy domain, tracing their development from asset-level simulations and supervisory control systems to hybrid, community-scale architectures that integrate multiple energy vectors, stakeholders, and governance layers. Drawing on recent literature published between 2022 and 2025, the review identifies key conceptual, computational, and institutional shifts underpinning this transition, including hybrid physics–data modelling, edge–cloud orchestration, co-simulation, and artificial-intelligence-assisted forecasting, alongside growing attention to interoperability, privacy, and social legitimacy. The analysis is anchored in the SMART (SMart transition to renewAble eneRgy communiTies) project, implemented within the Culatra2030 Sustainable Energy Community in southern Portugal. SMART is presented as an application-oriented DT framework that addresses persistent gaps in the literature, notably the limited long-term validation of DTs, the weak integration of participatory governance, and the misalignment between technical optimisation and community values. The proposed architecture conceptually couples distributed photovoltaics, energy storage, and electrified mobility with cooperative governance mechanisms. It integrates interoperable individual energy management systems, a central smart monitoring and control platform, and a web-based user interface that enables both operational coordination and citizen engagement. The paper argues that DTs are evolving into socio-technical infrastructures mediating technical performance, institutional design, and human behaviour, positioning renewable energy communities as living laboratories for energy transitions.

Electrical grids are undergoing a transformation driven by the increasing integration of renewable energy sources on the consumer side. This shift, alongside the electrification of consumption—particularly in areas such as electric mobility—has the potential to significantly reduce CO₂ emissions. However, it is also contributing to a rise in electricity prices due to growing demand and infrastructure costs. Paradoxically, these higher prices serve as a catalyst for further investment in renewable energy technologies by reducing the payback periods of such systems. Recent European legislation has accelerated this transformation by mandating the liberalization of energy markets. This regulatory shift enables the emergence of prosumers—consumers who are also producers of energy—by granting them the right to generate, store, and trade electricity using the existing distribution grid. In this new landscape, photovoltaic systems represent a viable and increasingly attractive investment option for both households and businesses. This study presents an economic evaluation of photovoltaic system investments across different European countries, focusing on key indicators such as payback periods and the impact of local solar irradiation on the resulting electricity price. The analysis provides insight into the varying economic feasibility of distributed solar energy deployment, offering a comparative perspective that supports both policymakers and potential investors in making informed decisions about renewable energy adoption.

There is currently exponential growth in the electric vehicle market, which will require an increase in the electrical grid capacity to meet the associated charging demand. If, on the one hand, the introduction of energy generation from renewable energy sources can be used to meet that requirement, the intermittent nature of some of these sources will challenge the mandatory real-time equilibrium between generation and consumption. In order to use most of the energy generated via these sources, mechanisms are required to manage the charging of batteries in electric vehicles, according to the levels of generation. An effective smart charging process requires communication and/or control mechanisms between the supply equipment and the electric vehicle, enabling the adjustment of the energy transfer according to the generation levels. At this level, the ISO 15118 standard supports high-level communication mechanisms, far beyond the basic control solutions offered through the IEC 61851-1 specification. It is, thus, relevant to evaluate it in smart charging scenarios. In this context, this paper presents the development of a charge emulation system using the ISO 15118 communication protocol, and it discusses its application for demand response purposes. The system comprises several modules developed at both ends, supply equipment and electric vehicles, and allows the exchange of data during an emulated charging process. The system also includes human interfaces to facilitate interactions with users at both ends. Tests performed using the implemented system have shown that it supports a demand response when integrated with a photovoltaic renewable energy source. The dynamic adjustment to charging parameters, based on real-time energy availability, ensures efficient and sustainable charging processes, reducing the reliance on the grid and promoting the use of renewable energy.

There is currently an exponential growth in the electric vehicle market, which will require an increase in the electrical grid capacity to meet the demand of charging. If, on the one hand, the introduction of energy generation from renewable sources can be used to meet that requirement, the intermittent nature of some of these sources poses challenges to the required real time equilibrium between generation and consumption. The impossibility of controlling generation from some of these sources leads to the attempt of controlling and manage the consumption of electricity, according with the levels of generation. In this context, the emergence of smart grids has introduced mechanisms that guarantee a balance between consumption and generation of electricity. One of these mechanisms is the smart charging of electric vehicles. Effective smart charging relies on communication between the supply equipment and the electric vehicle, en-abling the adjustment of the energy transfer according with the generation levels. Thus, there is a necessity for a standardised system that guarantees this communication. In this context, the ISO 15118 standard, allows high level communication mechanisms, much beyond the basic control solutions offered by the IEC 61851-1 specification. In this context, this paper presents the development of a charge emulation system, based on the ISO 15118 communication protocol and discusses its application for demand response purposes.