Spaces, Energy and Shared Resources: New Technologies for Promoting More Inclusive and Sustainable Urban Communities

Abstract

Renewable Energy Communities (RECs) are central to Europe’s strategy for reducing greenhouse gas emissions and advancing a sustainable, decentralized energy system. RECs aim to transform consumers into prosumers—individuals who both produce and consume energy—thereby enhancing energy efficiency, local autonomy, and citizen engagement. This study introduces a novel Geographic Information System (GIS)-based methodology that integrates socio-economic and spatial data to support the design of optimal REC configurations. QGIS 3.40.9 “Batislava” tool is used to simulate site-specific energy distribution scenarios, enabling data-driven planning. By combining a Composite Energy Vulnerability Index (CEVI), Rooftop Solar Potential (RSP), and the distribution of urban gardens (UGs), the approach identifies priority urban zones for intervention. Urban gardens offer multifunctional public spaces that can support renewable infrastructures while fostering local resilience and energy equity. Applied to the city of Rome, the methodology provides a replicable framework to guide REC deployment in vulnerable urban contexts. The results demonstrate that 11 of the 18 highest-priority areas already host urban gardens, highlighting their potential as catalysts for collective PV systems and social engagement. The proposed model advances sustainability objectives by integrating environmental, social, and spatial dimensions—positioning RECs and urban agriculture as synergistic tools for inclusive energy transition and climate change mitigation.

1. Introduction

The Italian and European energy systems are currently undergoing a profound transformation, driven by multiple converging factors [1]. Chief among these is the need to meet the ambitious decarbonization targets outlined in the European Green Deal [2], alongside the repercussions of recent geopolitical instability—particularly the conflict in Ukraine—which has intensified dependence on fossil fuels and triggered a sharp rise in energy prices [3,4]. These developments have exposed the vulnerabilities of centralized energy systems and underscored the urgent need to diversify energy sources to enhance security and resilience [5,6]. Additionally, the trend of growing global energy demand, which, according to a recent report by the International Energy Agency, is expected to continue rising at an average annual rate of 3.4% until 2026 [7], further complicates the scenario. The increasing energy demand in urban areas results from population growth, the concentration of economic activities, and changes in consumption patterns related to industry, transport, and buildings [8]. It is estimated that approximately 70% of global CO₂ emissions originate from urban environments, with the transport and building sectors representing two of the most significant sources [9]. These dynamics underscore the urgency of transitioning to energy sources that generate substantially lower emissions, such as renewables.

The concept of “transitioning away from fossil fuels” was formally acknowledged in the final declaration of COP28 in Dubai [10], marking a global commitment to the gradual phase-out of fossil energy sources. This transition entails replacing coal, oil, and gas with low-carbon energy alternatives such as hydroelectric, solar, wind, and nuclear power, which emit approximately 99% to 99.5% less CO₂ [11].

Previous energy policies, while promoting the adoption of renewable technologies, have often focused primarily on economic aspects, favoring initiatives and projects centered on financial sustainability and neglecting the concrete involvement of local communities [12]. It is therefore crucial to accelerate the implementation of renewable energy sources at the local level to increase the resilience of the energy system, not only in terms of supply security but also with regard to political autonomy [13]. Sustainable energy is increasingly acknowledged as a fundamental human right and a critical enabler for the achievement of the United Nations Sustainable Development Goals, particularly SDG 7 and SDG 11. These goals emphasize the essential connection between energy provision and urban development, aiming to guarantee universal access to affordable, reliable, and modern energy services [14,15]. Moreover, they highlight the importance of fostering urban well-being, mitigating social inequalities, protecting the environment, and addressing climate change through integrated energy and city planning [16].

Within this framework, the concept of energy poverty emerges as a critical issue. According to the definition provided by the European Commission, energy poverty refers to a condition in which “energy bills represent a high percentage of consumers’ income, or when they must reduce their household’s energy consumption to a degree that negatively impacts their health and well-being” [17,18]. Three primary drivers contributing to the increasing vulnerability of households to (often hidden) energy poverty are limited household income, inadequate energy efficiency of residential buildings, and the persistent rise in energy costs.

In this context, decentralized energy systems have gained traction as a viable alternative to traditional centralized models [19,20]. These systems distribute energy generation and management across local communities, allowing for greater autonomy and efficiency. The integration of renewable sources—such as solar, wind, and biomass—enhances community resilience and reduces transmission losses, addressing both environmental and socio-economic challenges.

Urban environments face growing pressures in balancing spatial efficiency, environmental sustainability, and equitable resource distribution. Within this context, Renewable Energy Communities (RECs) have emerged as a key model for promoting decentralized energy generation, citizen engagement, and equitable access to clean energy [21,22,23,24]. Recent advances in urban design emphasize a transition toward integrated models that combine spatial equity, energy efficiency, and multifunctional infrastructures. Mobaraki et al. [25] argue that sustainable urban design should move beyond aesthetic or functional considerations, adopting a systemic approach that integrates energy resilience, ecological regeneration, and community engagement to shape adaptive and inclusive cities. These paradigms align with the REC model by promoting decentralized infrastructures that respond to both environmental and social priorities.

RECs promote cooperation among members to generate, share, and consume energy locally, enhancing self-sufficiency and reducing reliance on centralized grids. In addition to facilitating the transition towards a more sustainable and low-carbon energy system, RECs contribute to strengthening the local economy and enhancing community resilience. Generating energy close to consumers not only reduces losses but also increases system reliability, making communities more independent and less vulnerable to supply interruptions [26]. Thus, RECs not only support the energy transition but also serve as a fundamental tool to achieve the ambitious carbon neutrality targets by 2050, as established by the European Union [27].

Energy communities consist of aggregations of private individuals, businesses, third sector entities, and local administrations collaborating for the joint development of renewable energy production plants, aiming to meet internal demand and feed surplus energy into the grid [28]. This model, introduced by Alvin Toffler in 1980 [29], finds application in modern socio-economic practices, supported by the increasing diffusion of information and communication technologies. Beyond their technical and infrastructural aspects, energy communities are also social constructs shaped by the interactions and roles of diverse actors. A substantial body of research has examined the involvement of citizens as key actors within renewable energy communities. Musolino et al. [30], for example, explored how local contextual factors influence the composition and characteristics of actor networks associated with energy communities, emphasizing regional disparities between northern and southern Italy. In a complementary line of inquiry, De Vidovich et al. [31] investigated the organizational structures adopted by these communities. Berrou and Soulier [32] contributed a methodological approach based on Actor-Network Theory to better understand the social dynamics driving the emergence of energy communities. Other studies have addressed the broader social impacts of such initiatives within the European context [33], and examined how the social, economic, and technical configurations of energy communities evolve in response to updates in European energy-sharing directives.

RECs are defined as “sets of renewable energy technologies used or shared by a group of individuals within a specific geographic area,” positively influencing the economic, environmental, social, and political dimensions of communities [34]. In this context, the possibility of being simultaneously producers and consumers of energy (prosumers) enables the adoption of hybrid organizational forms that integrate production, consumption, and energy sharing. The interaction among members of energy communities, facilitated by digital systems, allows for the optimization of self-consumption, reducing energy costs and contributing to more efficient resource management [35].

RECs, including cooperatives and energy clusters, represent some of the most promising solutions to ensure self-sufficient and sustainable supply, while simultaneously reducing social inequalities and promoting active citizen participation [36]. The Renewable Energy Directive (RED II) promotes active consumer participation and encourages member states to implement support schemes for RECs. The European directives on renewable energy (2018/2001/EU, RED II) and the energy market (2019/944/EU, IEM) establish guidelines for the involvement of individuals and communities in the production, consumption, and sharing of renewable energy, creating a regulatory framework that facilitates the transition towards a decentralized and more inclusive energy system [37].

In Italy, Law No. 8 of 2020 has transposed these directives and introduced incentives for the creation of RECs, improving the national regulatory framework and facilitating community participation [38].

Several studies have undertaken comparative analyses of the financial instruments available to support the establishment of renewable energy communities, particularly in light of recent legislative developments. These investigations often serve as a foundation for assessing the economic feasibility of such communities by calculating key economic performance indicators, including Net Present Value, Internal Rate of Return, and Payback Period. This financial dimension complements the technical and social aspects of REC implementation, offering a comprehensive basis for decision-making and policy design [39].

Numerous applications of RECs are emerging across sectors. A. Buonomano et al. [40] propose RECs in maritime ports to enhance local energy self-sufficiency and environmental performance. These communities enable ports to locally generate, consume, and manage renewable energy, thereby reducing dependence on external sources and improving environmental sustainability.

In the agricultural sector, RECs offer opportunities to integrate renewable energy production with traditional farming activities [41]. In the industrial context, RECs can contribute to lowering energy expenses and facilitating the transition toward more sustainable practices. Recent studies highlight that the implementation of RECs within industrial districts can lead to significant energy savings and improved operational performance [42].

Barbaro et al. [43] explore rooftop photovoltaic systems on schools as key infrastructure for Solidarity Renewable Energy Communities (SRECs), using surplus energy for social purposes. They analyze how to meet the energy demand of schools while simultaneously sharing excess energy with the surrounding community, thus promoting energy self-sufficiency and sustainability. Schools, with their large rooftops, represent an ideal surface for the installation of photovoltaic systems. These systems can generate clean energy during daylight hours, covering part of the schools’ energy consumption and reducing operational costs. The excess energy produced can be shared by accessing government incentives that allow the generation of cash flows which, depending on the statutes adopted by the RECs, can be redistributed for solidarity activities.

In this regard, the Municipality of Rome has approved regulations that allow both the establishment of RECs with systems installed on buildings of Rome Capital undergoing redevelopment, and the use of rooftops of schools and municipal buildings to install photovoltaic systems serving energy communities promoted by third sector entities [44].

RECs are used as tools to raise awareness among students and communities about the importance of new energy consumption patterns and self-consumption. Schools become catalysts for spreading energy awareness through projects involving renewable infrastructures, laboratories, and collaborations with public and private entities.

RECs and urban gardens (UG) are increasingly seen as complementary strategies that transform urban spaces into hubs for sustainable resource management. While RECs decentralize energy production through collective ownership, urban gardens reclaim underutilized land for food security, social cohesion, and ecological balance. Their integration forms a novel paradigm where space, energy, and community intersect to advance urban sustainability.

Schmid et al. [45] highlight the multifunctionality of PV systems and their synergy with green infrastructure.

Di Nucci et al. [46] examine the transfer and implementation of multifunctional energy gardens, focusing on their capacity to integrate renewable energy production with communal green spaces. Their analysis emphasizes the role of participatory governance and the spatial integration of energy infrastructures within urban environments. Social Farms & Gardens present an overview and case studies of renewable energy installations in community gardens, emphasizing the environmental, economic, and social benefits of integrating clean energy with shared urban green resources. In his thesis, Bolsi R. [47] examines the real-world implementation of energy communities and their collaboration with local stakeholders for shared resource management and spatial optimization in urban areas.

These initiatives underscore the transformative potential of integrated approaches that merge renewable energy systems with community-driven green spaces, fostering resilient, inclusive, and sustainable urban environments.

Emerging Technologies to Enhance the Strategic Planning and Implementation of Renewable Energy Communities

RECs hold significant potential to address barriers to participation in the ongoing energy transition, particularly among disadvantaged and low-income populations—often referred to as energy-poor communities. Despite their inclusive promise, ensuring equitable access to community energy initiatives remains a critical challenge.

New technologies play a pivotal role in fostering more inclusive and sustainable urban communities, enabling innovative approaches to energy production, spatial planning, and social engagement.

Digital tools such as Geographic Information Systems (GIS), Internet of Things (IoT), Digital Twins (DTs), energy management platforms and smart meters, facilitate the integration of renewable energy at the local scale, allowing for data-driven decisions tailored to specific urban needs [48].

In particular, GIS have long served as a strategic tool in supporting urban and energy system planning, and have been widely used in renewable energy identification, building footprint generation, and energy management [49,50].

GIS transcends traditional mapping by enabling multi-criteria decision analysis, dynamic resource modeling, and participatory planning. This approach permits the identification of optimal locations for renewable installations (e.g., solar PV on urban gardens or rooftops) by overlaying solar irradiance, land use, building density, and grid connectivity data.

One of the most significant applications of GIS in the context of Renewable Energy Communities lies in identifying optimal areas for renewable energy generation. Through the analysis of spatial data, it is possible to examine various environmental factors—such as solar irradiance and wind speed—in order to locate zones with the highest potential for energy production. This capability proves particularly valuable for determining the most suitable sites for the installation of photovoltaic or wind energy systems, thereby enhancing the overall efficiency of renewable energy deployment. In addition, GIS plays a critical role in the mapping and management of local electricity distribution networks [51]. Given that RECs rely on the effective integration of renewable sources into the grid, GIS enables the visualization and analysis of the existing network infrastructure and energy flows, supporting strategic planning for interventions aimed at optimizing energy distribution.

A notable example is the Community Solar Opportunities Map (CSOM), a GIS-based tool developed to identify and prioritize sites for community solar projects in Los Angeles County, illustrating how spatial analysis can guide the equitable and efficient siting of renewable energy infrastructure in complex urban environments [52]. The tool presents key attributes related to technical and administrative constraints for the siting of community solar projects; however, it does not prioritize sites based on socio-economic criteria, nor does it take urban gardens into account.

Research by F. Vecchi et al. [53] and F. Santana-Sarmiento et al. [54] explores how GIS can be used to define optimal locations that guarantee the highest energy yield from renewable energy production plants. However, most existing studies, such as the one conducted by A. Buonomano et al. [55], focus primarily on the technical and spatial aspects of renewable resource distribution and energy demand, while overlooking a comprehensive assessment of the socio-economic impacts associated with the spread of RECs. In particular, the role of local communities in accessing the economic benefits generated by such initiatives, as well as the territorial inequalities linked to the energy transition, remains largely underexplored.

Within this framework, the European project SUN4U [56], in which the authors’ institution—the Interdepartmental Research Center on Territory, Building, Restoration and Environment (CITERA)—is actively involved, has developed an open-source digital platform aimed at promoting RECs in the urban context of Rome. The platform integrates advanced spatial analysis tools in a GIS environment and includes a georeferenced database encompassing both RECs and urban gardens at the national scale.

By calculating the Roof Solar Potential (RSP) of over 200,000 buildings in Rome—categorized into large roofs (with an area exceeding 500 m²) and public roofs managed by the Municipality of Rome or other public bodies—SUN4U provides an operational tool for the analysis and strategic planning of RECs. This platform enables the generation of flexible energy scenarios that can be tailored to local needs in real time, thus fostering more efficient and resilient energy production and consumption strategies.

In this context, urban gardens emerge as strategic assets, not only for urban regeneration and social cohesion but also for the development of multifunctional urban ecosystems. Originally rooted in grassroots movements as a response to unchecked urban sprawl, these initiatives have progressively been incorporated into public policies for urban planning and regeneration. Beyond their environmental role, urban gardens address multiple community needs, including food security, social inclusion, recreational and educational opportunities, psychological well-being, and, more recently, local energy planning.

In Rome, the first attempt at officially mapping these spaces dates to the “Census of Spontaneous Gardens within the Municipality of Rome and inside the G.R.A.” (2003–2006), which identified 67 sites comprising over 2300 informal gardens across approximately 89 hectares, albeit through a partial survey. This initiative was followed in 2010 by the Zappata Romana project, which developed an interactive Google Maps platform dedicated to shared community gardens [57].

Building on this trajectory, the SUN4U project has initiated a comprehensive mapping of all urban gardens across Italy, with data currently being analyzed within the Horticer project, coordinated by CITERA.

Based on these premises, this study proposes an innovative methodology that integrates GIS-based tools for the overlay and combined analysis of socio-economic and spatial datasets, to identify optimal configurations for REC development. Specifically, the proposed approach identifies socio-economically vulnerable areas located near urban gardens, considering these sites as potential energy hubs for shared photovoltaic production.

This study addresses a significant gap in the existing literature by integrating technical, spatial, and socio-economic dimensions into a single decision-support framework for the planning of RECs. While prior research has often examined these factors in isolation, our approach combines the Combined Energy Vulnerability Index (CEVI), RSP, and the distribution of UGs—three indicators rarely considered in conjunction. This triangulated integration enables the identification of urban areas that are simultaneously characterized by high levels of energy poverty, high technical potential for solar energy generation, and spatial proximity to underutilized green infrastructure. Such a combination constitutes the core innovation of the study, offering a multidimensional lens through which to assess REC feasibility and priority areas for intervention. By explicitly linking social equity, technical viability, and spatial opportunity, the proposed framework allows for a more targeted and inclusive strategy for REC deployment—one that is responsive to both infrastructural and socio-environmental needs.

The methodology, applied to a specific case study, demonstrates how the integration of RECs and urban gardens can optimize the use of natural resources, promote local energy self-sufficiency, and enhance urban resilience. This perspective contributes to advancing sustainability goals by fostering environmental awareness and encouraging active community participation in the energy transition, positioning RECs as pivotal instruments for climate change mitigation and inclusive urban development.

Therefore, the paper is organized as follows: Section 2 presents the proposed methodology; Section 3 details the application to the case study; Section 4 reports the results; Section 5 discusses the findings; and finally, Section 6 provides the conclusions and outlines future developments.

2. Materials and Methods

The methodological approach adopted in this study aims to integrate socio-economic vulnerability data with electricity consumption datasets and the spatial distribution of urban gardens, to identify optimal sites for the development of RECs. This multi-phase approach employs advanced digital tools, with a particular emphasis on Geographic Information Systems (GIS), to support data integration, spatial analysis, and visualization.

GIS technologies provide a robust platform for the analysis and interpretation of geospatial data, enabling the identification of vulnerable urban areas and informing the design of context-sensitive, sustainable energy interventions. By aligning areas of high energy demand and socio-economic vulnerability with renewable energy production potential, this method seeks to spatially optimize the deployment of RECs.

The proposed methodology is structured into the following main phases (Table 1):

• Socio-economic data collection. The first phase involved the systematic collection of socio-economic data at the urban area level. Key variables included household income, energy consumption, and the distribution of energy bonus recipients, sourced from ISTAT (the Italian National Institute of Statistics) census data, ARETI electricity consumption records, and the CAF Network. These datasets provided the foundation for constructing the CEVI, a synthetic indicator designed to assess energy poverty across urban areas.
• Socio-economic vulnerability mapping. In the second phase, socio-economic indicators were georeferenced and analyzed through GIS tools to produce thematic maps of spatial vulnerability. The CEVI—based on normalized indicators of income, consumption, and bonus recipients—enabled the identification of urban zones characterized by heightened energy-related and socio-economic disadvantage. This mapping phase provided a spatial basis for prioritizing zones in need of targeted interventions.
• Rooftop solar potential and urban gardens mapping. The third phase focused on assessing the potential for renewable energy production by mapping the solar potential of rooftops and the distribution of urban gardens. Data from the SUN4U project and municipal sources were used to evaluate the suitability of over 198,000 rooftops and more than 80 urban gardens for hosting photovoltaic installations. This mapping identified areas where the integration of RECs and urban gardens could maximize local energy production and foster community engagement [58].
• Integration and spatial overlay analysis. The final phase integrated the datasets generated in the previous steps through GIS-based spatial overlay techniques. By superimposing maps of socio-economic vulnerability, rooftop solar potential, and urban garden locations, high-priority zones for REC implementation were identified. This integrated spatial analysis allowed for the strategic localization of interventions aimed at simultaneously addressing energy poverty, enhancing community resilience, and promoting socially equitable energy transitions.

Table 1. Adopted phases and related description, objectives and data for the paper methodology.

Phase	Description	Objective	Tools/Data	References
Socio-Economic Data Collection	Collected socio-economic, income, energy use, and bonus recipient data for Rome’s urban areas	Build the CEVI to assess energy poverty	ISTAT census, ARETI electricity data, CAF Network, SUN4U data	[59]
Socio-economic vulnerability mapping	Used GIS to georeference and map indicators of energy poverty and vulnerability across neighborhoods	Spatially represent energy poverty and correlate with REC initiative distribution	GIS software, Map Algebra, CEVI indicators (V1, V2, V3)	[60,61]
Rooftop solar potential and urban gardens mapping	Assessed photovoltaic potential of 198,000 rooftops, focusing on high-density inner-city areas	Evaluate REC development potential based on available rooftop solar energy	SUN4U project data, solar irradiation, rooftop/energy data	[62,63,64]
	Mapped 80+ urban gardens, evaluating their suitability for hosting or promoting REC initiatives	Identify gardens as catalysts for social aggregation and REC growth in vulnerable locations	Geolocation, SUN4U assessments, socio-economic vulnerability maps, urban garden data
Integration and spatial overlay analysis	Combined maps of socio-economic vulnerability, rooftop solar potential, and urban garden locations	Identify high-priority areas for REC development	GIS software, socio-economic vulnerability maps, rooftop/energy data, urban garden data	[65,66]

Table 1. Adopted phases and related description, objectives and data for the paper methodology.

Phase	Description	Objective	Tools/Data	References
Socio-Economic Data Collection	Collected socio-economic, income, energy use, and bonus recipient data for Rome’s urban areas	Build the CEVI to assess energy poverty	ISTAT census, ARETI electricity data, CAF Network, SUN4U data	[59]
Socio-economic vulnerability mapping	Used GIS to georeference and map indicators of energy poverty and vulnerability across neighborhoods	Spatially represent energy poverty and correlate with REC initiative distribution	GIS software, Map Algebra, CEVI indicators (V1, V2, V3)	[60,61]
Rooftop solar potential and urban gardens mapping	Assessed photovoltaic potential of 198,000 rooftops, focusing on high-density inner-city areas	Evaluate REC development potential based on available rooftop solar energy	SUN4U project data, solar irradiation, rooftop/energy data	[62,63,64]
	Mapped 80+ urban gardens, evaluating their suitability for hosting or promoting REC initiatives	Identify gardens as catalysts for social aggregation and REC growth in vulnerable locations	Geolocation, SUN4U assessments, socio-economic vulnerability maps, urban garden data
Integration and spatial overlay analysis	Combined maps of socio-economic vulnerability, rooftop solar potential, and urban garden locations	Identify high-priority areas for REC development	GIS software, socio-economic vulnerability maps, rooftop/energy data, urban garden data	[65,66]

3. Case Study

The methodological approach adopted to cross-reference data on socio-economic vulnerability—an indicator constructed from the distribution of energy subsidies, electricity consumption, and income levels—with the presence of urban gardens and RECs initiatives was implemented in the city of Rome.

The objective was to assess the spatial correlation among these three phenomena and to identify priority areas for the establishment of Renewable and Solidarity Energy Communities. This process involved the use of advanced digital tools, particularly GIS, to visualize, analyze, and integrate relevant geospatial data.

The integration of these datasets enabled a comprehensive spatial analysis, supporting the identification of neighborhoods where socio-economic vulnerability, urban agriculture, and REC initiatives converge, thus facilitating targeted strategies for the development of Solidarity RECs.

3.1. Socio-Economic Data Collection

In the initial phase, socio-economic data relating to the resident population in the various municipalities and urban areas (UA) of Rome were collected. The main sources for constructing the spatial indicator of energy vulnerability (CEVI) were:

• ISTAT data from the 2021 population census;
• Income data (ISTAT);
• Household electricity consumption data (source: ARETI Rome DSO);
• Data on Roman citizens receiving the energy bonus (source: Roma Capitale—CAF Network).

The Energy Bonus is a discount applied directly to electricity and natural gas bills for families in conditions of economic or physical hardship [59].

The sources for mapping communities, specifically Urban Gardens and RECs initiatives, were:

• The catalogue of Roman Urban Gardens conducted in collaboration with Replay Network (2025);
• The cataloguing of REC initiatives at various stages of development, carried out nationally within the SUN4U project (April 2025);
• The distribution of users in the Rome area registered on the SUN4U platform;
• Users registered on the SUN4U platform are potential consumers or prosumers of REC initiatives currently under development.

3.2. Socio-Economic Vulnerability Mapping

Using GIS, the collected data were georeferenced to produce thematic maps that illustrate various dimensions of socio-economic vulnerability across different neighborhoods in Rome, all in relation to the phenomenon of energy poverty.

Several factors contribute to the definition of energy poverty according to the EPAH (European Energy Poverty Advisory Hub) [60]:

• Excessively low energy consumption;
• A disproportionately high share of household income dedicated to energy expenses;
• Delays in paying utility bills;
• Inability to keep the home adequately warm in winter or cool in summer.

Due to the lack of sufficiently granular mapping to describe phenomena 2, 3, and 4, the analysis relied on the distribution of energy bonus recipients (2021) and average household income (2021), while for energy consumption (factor 1), the data were available. As a result, a new spatial indicator of energy vulnerability was defined: the CEVI. This indicator is constructed by appropriately weighting three normalized indicators:

• V₁ Recipients of the Energy Bonus (Rate of Perceivers/Residents calculated for each UZ—Urban Zone);
• V₂ Average annual household income (UZ below the mean);
• V₃ Average annual household electricity consumption (kWh/year in each UZ).

For each UZ, the CEVI is calculated using a map algebra methodology [61], represented as:

p₁ V₁ + p₂ V₂ + p₃ V₃

where pn denotes the specific weight assigned to each indicator, making it possible to weight the three distributions V₁, V₂, and V₃ with a vector whose components sum to 1 (p₁ + p₂ + p₃ = 1).

These three indicators were selected in this study because, when combined, they offer a robust representation of energy poverty in an urban context and are well-suited for GIS-based mapping. The following sections first present the three distributions individually, followed by the spatial analysis of their combined indicator.

3.2.1. V1. Mapping the Rate Bonus Energia Perceivers/Residents

Figure 1 presents the results of an overlay analysis of two datasets from 2021:

• The point distribution of Roman households receiving the energy bonus;
• The distribution of residents across the 154 UZ that subdivide the municipality of Rome.

This analysis allowed for the identification and classification of the V1 Bonus/Residents (B/R) index, which measures the density of energy bonuses relative to the resident population in each UZ. The index ranges from a minimum value of 0.002 to a maximum of 0.0277, represented by a gradient from black to red.

3.2.2. V2. Mapping the Medium Yearly Income of the Families

The distribution of average annual household income closely mirrors that of energy bonus recipients, confirming, in the geography of poverty, all neighborhoods of the eastern wedge as well as the areas of Corviale, Acilia, Labaro-Prima Porta, and Boccea, which are highlighted in red in Figure 2. The income data, initially calculated for the postal code (CAP) areas of Rome, were subsequently mapped into the UZ with only a limited loss of granularity in the distribution.

3.2.3. V3. Mapping the Medium Yearly Power Consumptions of the Families

The data provided by the local electricity distribution company ARETI for the UZ of Rome refer to the year 2021 and include both domestic and non-domestic consumption and users, regardless of the energy supplier with whom the contract was signed. The layer used consists exclusively of domestic consumption, which reflects inequalities in household energy use and can therefore be related to the risk of energy poverty. The analysis revealed a significant concentration of low energy consumption in specific high-density residential areas, depicted in black and grey in Figure 3, particularly within large peripheral urban agglomerations. In contrast, high levels of energy consumption are concentrated in the historic city center and in certain affluent peripheral areas, characterized by housing typologies such as villas or generally larger dwellings, represented by orange and red colors. This indicator also confirms a higher incidence of energy poverty in the eastern sectors of the city, as well as in areas such as Corviale, Acilia, Labaro, and Boccea.

For each UZ area, the CEVI is calculated using a map algebra approach, expressed as:

0.50 × V₁ + 0.25 × V₂ + 0.25 × V₃

This weighting scheme assigns double the weight to the Bonus/Residents (V₁) index relative to the other two indices (V₂ and V₃). V1 is considered the most robust, direct, and policy-grounded indicator for identifying energy poverty, as it is based on official data concerning recipients of the Energy Bonus—a form of financial support established by Italian legislation for households in economic hardship. Unlike V2 and V3, which rely on indirect variables and may be affected by settlement density or demographic composition, V1 enables a more precise detection of vulnerable households. For this reason, it was assigned a 50% weight, providing a solid empirical basis for the overall CEVI calculation. In contrast, V₂ and V₃ are influenced in certain areas by diverse settlement patterns and may underestimate vulnerability, particularly in the western periphery of the city, where socio-economic hardship remains prevalent. In the composite CEVI map, the point layers representing potential or existing RECs initiatives have been overlaid, allowing for the analysis of spatial correlations between these community-based initiatives and areas affected by energy poverty (Figure 4).

The measurement of the spatial correlation between REC initiatives and energy vulnerability was conducted in a straightforward manner, by synthesizing a single value for each UZ area that sums the SUN4U users and the actual and potential members of the mapped REC initiatives. This new index, representing the level of participation in REC initiatives, was then overlaid onto the vulnerability map. It should be noted that, according to Italian regulations, the development of REC initiatives is expected to occur within a perimeter known as the Conventional Area (CA or PCP), where the REC configuration must reside both in terms of consumers and prosumers, as well as shared RES (Renewable Energy Sources) installations. These areas correspond to the Perimeters of Primary Substations (PS), that is, the areas served by a high-to-medium voltage electrical transformation station, reflecting the contiguity of users on the electrical grid and the logic of distributed generation. The analysis conducted in this study, however, refers to the UZ areas, which are not very different from the primary substation PS areas, since the data underlying the CEVI specifically pertain to the UZ. Within a Platform for Energy Sharing (PCP) area, multiple RECs can be developed. Ideally, the upper limit for REC memberships in an urban context is determined solely by the number of active users present in the area and by the potential availability of distributed, local renewable energy generation. The first of the two maps presented below (Figure 5) summarizes the potential currently measured in terms of members participating in REC initiatives, as of April 2025, based on the aforementioned data. It should be noted that this representation does not aim to estimate the temporal evolution of the potential for REC membership.

This straightforward overlay enables an analysis of the correlation currently observed in the development phase of RECs in Rome with the geography of energy poverty and, more broadly, socio-economic disadvantages. In most cases, areas with lower vulnerability are the first to be involved in REC initiatives. However, following the promotional and support activities of the pilot projects Sun4All and Sun4U, several areas with a high CEVI are now also hosting REC development initiatives.

The distribution of the 760 users registered on the SUN4U platform, when overlaid with maps of the CEVI, serves—in the absence of other substantial data—as a good indicator of the potential overlap between REC initiatives and vulnerability. The SUN4U platform, in fact, freely welcomes users and user groups interested in establishing a local REC. As with the counting of bonus recipients among SUN4U users, users have been tallied for each urban zone and, consequently, for each conventional area. Examining the map of SUN4U user frequency in urban zones, it is noteworthy that a geography emerge which closely mirrors that of vulnerability, with the highest concentrations of users found in less vulnerable areas. This is because, in this initial phase of REC system development, promoters and so-called “enthusiasts” predominantly come from more affluent social classes, i.e., residents of less vulnerable areas.

When considering the distribution of REC group initiatives recorded by the SUN4U project, the situation improves towards a more equitable distribution. Among these initiatives are the 10 SUN4U pilots, which are evenly distributed: half are in vulnerable areas such as Corviale, Cinecittà, Pigneto, and Quarticciolo, having developed thanks to the specific support provided first by the Sun4All project and subsequently by Sun4U to the respective groups.

As expected, independently developed REC initiatives are more frequent in areas with a low combined energy poverty index (CVI). It can be stated that in 60% of cases, the development area has a low CEVI, while in 40% of cases, the urban zone presents high vulnerability. It would be of interest to verify, using the same methodology, the distribution of more advanced RECs in one or two years, as the success of such development—in terms of installed capacity available to RECs—will strongly depend on the investment capacity of the groups involved.

3.3. Mapping the RSP and Urban Garden for Each Urban Area

The development potential of RECs in a given area is largely determined by the availability of rooftop surfaces suitable for photovoltaic (PV) installations. Through analyses conducted within the SUN4U project, it has been possible to assess the annual production potential (kWh/year) of approximately 198,000 building rooftops within Rome’s inner city. The study therefore focused on the areas located inside the Grande Raccordo Anulare (GRA), characterized by a dense urban fabric and high population density—conditions that may present challenges for the optimal balancing of RECs.

In contrast, in outer or peri-urban areas, rooftop production potential generally exceeds local energy demand, a pattern commonly observed in rural and semi-rural contexts. For each rooftop within the study area, data are available on solar irradiation, total surface area, usable area, installable capacity (kWp), and expected annual energy production (kWh/year). It is important to note that, within the REC model, only 30–40% of the annual PV energy produced (i.e., daytime energy) is typically consumed simultaneously and thus can be virtually exchanged among community members. In the case of prosumer installations, a certain share of production is self-consumed on site, with the percentage varying significantly according to user typology and activity patterns.

Accounting for these efficiency and reduction factors, Figure 6 classifies annual per capita RSP according to a scale representing varying levels of sufficiency—ranging from insufficient to barely sufficient, and up to different degrees of surplus relative to local energy demand. This analysis assumes an ideal REC scenario, in which all residents within a given UZ could benefit from the full rooftop potential of that zone. The findings indicate that peripheral areas with lower population density tend to exhibit substantial energy surpluses, whereas in the compact urban core, rooftop surfaces are often insufficient to meet local energy needs. In the historic city center, despite lower population density—further accentuated by gentrification—and theoretically sufficient rooftop PV potential, two critical limitations emerge: (1) many rooftops are unusable due to heritage and landscape protection regulations, and (2) high daytime energy demand from commercial and service-sector activities reduces the surplus available for residential consumption.

In parallel, a comprehensive mapping of urban gardens within the municipal territory was undertaken. More than 80 active urban gardens were geolocated, including the Garbatella Urban Gardens, Casal Brunori, Tor Fiscale, Tre Fontane Urban Gardens, among others. These sites were assessed—drawing on the work conducted within the Sun4U project—for their potential to host or facilitate the development of REC initiatives, given the presence of active local communities. In many cases, the availability of shared spaces further enables the installation of collective photovoltaic systems. Together, these factors position urban gardens as particularly promising sites for fostering locally driven, citizen-led REC models (ref. cit.).

An analysis of their spatial distribution in relation to the geography of socio-economic vulnerability suggests that urban gardens may serve as key catalysts for community engagement around the REC model, particularly among more vulnerable groups. In this way, they may offer a concrete means of advancing the Just Transition principle that underpins REC initiatives. Furthermore, when their locations are compared with the map of optimal RECs based on annual per capita RSP, it becomes evident that urban gardens are more frequently situated in areas outside the city center.

However, where they are located within UZ characterized by high residential density and large-block building typologies, these gardens can provide valuable spaces for the deployment of collective photovoltaic systems as part of REC projects.

4. Results

The application of the proposed methodology in the city of Rome provided valuable insights into the spatial correlation between socio-economic vulnerability, rooftop solar potential, and the distribution of urban gardens, thereby facilitating the identification of priority areas for the development of RECs.

Through a GIS-based spatial overlay analysis, the study integrated these three dimensions into a set of composite maps, enabling the identification of priority areas for the establishment of RECs.

To systematically assess intervention priorities, the study introduced a synthetic Priority Indicator (IndPrior), calculated using the following weighted formula:

0.5 × I₁ + 0.3 × I₂ + 0.2 × I₃

where:

• I₁ corresponds to the CEVI;
• I₂ represents the RSP;
• I₃ reflects the presence of UG within each urban zone (a value of 0 indicates the absence of urban gardens, 0.5 denotes the presence of one urban garden, and 1 corresponds to the presence of two urban gardens.).

This weighting scheme emphasizes the social dimension of energy transition by assigning greater importance to vulnerability (I₁), while also incorporating technical feasibility (I₂) and the presence of urban gardens (I₃). The weighting scheme adopted for the Priority Indicator maintains the same logic as that used for the CEVI index, giving greater prominence to the social component over the technological aspect represented by the RSP. This prioritization ensures methodological coherence throughout the study by emphasizing social vulnerability as a key factor in the energy transition process. This subjective choice was guided by literature emphasizing the importance of social vulnerability in planning sustainable energy initiatives.

With specific regard to I₃, the choice to use a discrete scale (0, 0.5, 1) was driven by the need to develop a synthetic and replicable proxy indicator, capable of reflecting the presence or absence of urban gardens in a way that is not affected by data inconsistencies or the difficulty of standardizing more complex variables (e.g., precise surface area, accessibility, management type, or level of community engagement).

This simplified representation enabled the identification of spatial patterns across urban zones during the exploratory phase of the analysis, ensuring comparability and consistency within the overall methodological framework. While this approach treats all gardens equally, it facilitates a normalized and transparent assessment of their spatial distribution.

Based on the resulting scores (Supplementary Materials), the urban zones were classified into three priority levels (Figure 7):

• High priority (IndPrior ≥ 0.40): areas with high vulnerability and good infrastructural readiness;
• Medium priority (0.30 ≤ IndPrior < 0.40): areas with a moderate combination of vulnerability and solar/agricultural potential;
• Low priority (IndPrior < 0.30): areas characterized by lower vulnerability and limited resource availability.

The analysis was conducted on UZ located within the Grande Raccordo Anulare (GRA), where urban morphology and socio-economic conditions are relatively homogeneous. These central areas present more critical challenges—and, simultaneously, more opportunities—for the integrated development of RECs and urban agriculture. In contrast, the peripheral zones beyond the GRA, while offering greater availability of space due to lower residential density, display a different configuration of constraints and potentials, requiring context-specific adaptation of the proposed framework.

The GIS-based mapping identified 18 UZ as high priority, 32 as medium priority, and all remaining areas—accounting for over 50% of the analyzed zones—as low priority. Notably, 11 of the 18 high-priority zones were found to already include urban gardens, thereby empirically confirming the validity of the initial hypothesis regarding the spatial co-occurrence of socio-environmental need and resource potential.

These 11 zones, each registering a Priority Indicator score above 0.4, represent areas where both socio-economic vulnerability and resource availability converge. While this spatial overlap reinforces the proposed framework, a detailed analysis of the shared characteristics of these zones—such as building typologies, population density, urban morphology, or the presence of targeted social programs—was not included at this stage. Such an investigation could provide valuable insights into the structural or policy-driven factors facilitating the emergence of urban gardens in vulnerable areas, and will be considered in future research aimed at refining the prioritization model through a more comprehensive socio-spatial lens.

These findings demonstrate that the integration of GIS-based tools, CEVI, and urban gardens enables the precise identification of priority areas for the implementation of RECs, addressing both energy poverty and urban sustainability.

The methodology highlights the potential of urban gardens as catalysts for community-led energy initiatives, particularly in socio-economically disadvantaged neighborhoods, thereby promoting the principles of a just energy transition.

5. Discussion

This study proposes an innovative approach to the development of RECs through the integration of urban gardens and the application of GIS for the spatial analysis of socio-economic vulnerabilities, applied within the urban context of Rome. The developed methodology, grounded in the CEVI and integrated spatial analysis, represents a significant contribution to fostering an equitable and sustainable energy transition. RECs serve as an effective model for energy production and sharing, enabling collaboration among citizens, businesses, and local authorities to generate electricity from renewable sources and distribute it within localized networks [62]. This approach not only promotes collective self-consumption and reduces reliance on fossil fuels but also addresses socio-economic vulnerabilities by enhancing equitable access to energy and reducing costs for disadvantaged populations.

The proposed methodology introduces several innovations that advance the theoretical and practical framework for REC development in urban settings. Firstly, the integration of socio-economic and spatial datasets through the CEVI marks a significant departure from traditional approaches, which often prioritize technical aspects of renewable energy production over social considerations.

By combining normalized indicators of energy bonus recipients, average household income, and electricity consumption, the CEVI enables a holistic assessment of energy poverty at the UZ level. This facilitates the precise identification of areas with heightened socio-economic vulnerability, ensuring that RECs are strategically implemented to address energy inequalities and promote energy justice. Secondly, the integration of urban gardens as multifunctional hubs for RECs represents a novel paradigm. Unlike prior studies focusing primarily on infrastructures such as public or educational building rooftops, this study positions urban gardens as spaces that synergize energy production, social cohesion, and urban regeneration. The mapping of over 80 urban gardens in Rome, conducted within the SUN4U project, highlights their potential as sites for collective photovoltaic installations and as catalysts for community engagement, particularly in vulnerable areas. This catalytic role is not limited to the provision of physical space. Insights from the SUN4all and SUN4U projects—coordinated since 2022 by the CITERA research group—demonstrate that urban gardens often host pre-existing networks of trust, collaboration, and shared values, especially when supported by third-sector organizations. Engagement activities carried out in these contexts have successfully involved both vulnerable and non-vulnerable residents, showing that community gardens can serve as platforms for inclusive participation and co-learning. In this setting, communities already active in sustainability, food self-production, and social exchange find themselves empowered—particularly when supported by clear regulatory frameworks for RECs and enabling tools such as the SUN4U platform—to extend their commitment into the domain of collective energy generation. This convergence of social capital and technological infrastructure creates fertile ground for the emergence of trust-based, citizen-led energy communities.

Photovoltaic technology emerges as a reference solution due to its scalability, declining costs, and adaptability to urban environments. By integrating PV systems with urban gardens, RECs optimize spatial efficiency in dense cities, combining clean energy generation with benefits such as enhanced food security, reduced urban heat island effects, and improved air quality. This approach aligns with the principle of a just transition, ensuring that disadvantaged communities gain access to the social and economic benefits of renewable energy initiatives. Thirdly, the use of advanced GIS tools provides a flexible and scalable operational framework for REC planning. The SUN4U platform, incorporating a georeferenced database of over 198,000 buildings and urban gardens, enables real-time generation of tailored energy scenarios based on local needs. By cross-referencing socio-economic data with urban garden locations and rooftop solar potential, GIS facilitates the precise identification of areas that would benefit most from REC development.

However, the study is currently limited by its exclusive focus on rooftop solar potential and urban gardens, neglecting other renewable sources such as wind or biomass. While photovoltaic systems are particularly suited to Rome’s urban context, exploring alternative sources could diversify REC configurations, especially in peri-urban areas with greater spatial availability. Nevertheless, this methodological focus is the result of a deliberate choice grounded in both technical feasibility and contextual suitability. An important justification for the prioritization of PV technology lies in its superior compatibility with dense urban environments, where spatial constraints, regulatory limitations, and building typologies significantly shape the viability of energy infrastructure. While wind energy systems may offer higher theoretical efficiency, their effective deployment in built-up areas is far more complex and less predictable. Urban settings are typically characterized by turbulent airflows, irregular morphologies, and numerous physical obstructions—such as buildings, vegetation, and infrastructure—that reduce wind speed and disrupt consistency at the height of small-scale turbines.

By contrast, solar energy is far more accessible in urban contexts, particularly through rooftop PV installations that benefit from widespread availability, modular design, and decreasing implementation costs. Importantly, micro-wind turbines generally require a minimum average wind speed of approximately 3.5 m/s to operate efficiently—a condition that is rarely met with reliability in most city environments. Additional technical constraints—such as wind direction variability, atmospheric instability, and crosswind losses—further limit their performance. Moreover, installing wind energy systems on buildings entails stricter compliance with national structural design codes concerning load-bearing capacity, vibration control, and noise emissions, posing additional barriers to widespread adoption [63].

Given these challenges, the decision to center the methodology on PV systems represents a strategic and context-sensitive approach, aimed at ensuring technical feasibility, replicability, and scalability—especially in the early phases of REC implementation. Nonetheless, the inclusion of other renewable energy sources, such as wind and biomass, remains a promising avenue for future research. Their integration could enhance the resilience and diversification of RECs, particularly in low-density or peri-urban areas where spatial conditions and land use patterns differ substantially. Adapting the proposed framework to incorporate these technologies—supported by tailored spatial and regulatory analyses—would significantly extend its applicability across varied territorial contexts.

Notably, the proposed methodological approach enables the rapid identification of priority intervention zones suitable for establishing RECs at urban gardens, without the immediate integration of detailed behavioral consumption data. While such data are vital for optimizing energy sharing, ensuring sustained community engagement, and maximizing socio-environmental impacts, they were intentionally omitted to favor a swift spatial analysis based on socio-economic proxies [64]. However, the importance of user behavior in REC models is underscored in the literature: consumer load profiles, prosumer engagement levels, and flexibility services all significantly influence community performance and acceptance [65].

Consequently, the current model relies on static socio-economic indicators, without capturing the dynamic and seasonal variability of real energy practices. These behavioral dimensions could be analyzed and incorporated in future research by leveraging digital technologies, such as IoT-enabled smart meters and user interaction platforms. For example, the study of Giordano et al. [66] on IoT-aware energy exchange demonstrates how sensor networks and prosumer clustering can enable real-time load balancing and peer-to-peer energy sharing within energy communities.

Furthermore, although the CEVI represents an innovative tool for mapping energy poverty, it is based on indirect measures (energy bonus recipients, income, average consumption) and does not account for direct indicators such as thermal comfort, building energy efficiency, or utility payment arrears—all of which would greatly enrich the vulnerability analysis.

An additional limitation concerns the spatial transformation of income data. Originally available at the postal code (CAP) level, these data were aggregated and mapped onto Urban Zones (UZs) to ensure alignment with the spatial units used for solar potential and urban garden mapping. While this procedure enabled methodological coherence across the integrated analysis, it inevitably resulted in a partial loss of spatial granularity. In particular, the use of averaged values across UZs may have attenuated intra-zonal socio-economic heterogeneity, potentially introducing a risk of ecological fallacy—that is, inferring individual or localized conditions from aggregated data. Although this transformation was necessary to enable spatial integration within the proposed framework, it should be considered when interpreting the results related to vulnerability. Future studies could mitigate this limitation by employing higher-resolution socio-economic data (e.g., at the census tract level), which would allow for more precise identification of vulnerable groups and a more nuanced understanding of energy poverty dynamics.

6. Conclusions and Future Developments

This study has presented a methodological framework for the spatial identification of priority areas for the implementation of RECs, integrating socio-economic indicators with geospatial analysis. Applied to the urban context of Rome, the model leverages the CEVI and the spatial distribution of urban gardens to identify zones where RECs can effectively address both energy poverty and socio-environmental inequalities. The results demonstrate the potential of this approach to support equitable and site-sensitive energy transition strategies, particularly in densely built environments where traditional infrastructure-led solutions may be less feasible.

By focusing on rooftop PV systems and the strategic use of urban gardens, the methodology enables a scalable and replicable model tailored to cities with complex urban morphologies. The findings confirm that integrating green infrastructure with decentralized energy generation can produce synergies between environmental sustainability, social inclusion, and spatial justice.

The context of Rome, in particular, offers unique opportunities to transform community urban gardens into hubs where sustainability can be pursued through both healthy food production and clean energy generation. This study draws inspiration from the availability of two municipal regulations closely aligned with its objectives: the regulation issued in October 2024 concerning the establishment and management of Community Urban Gardens (CUGs) within green areas of Roma Capitale, and the regulation on the allocation of areas and photovoltaic systems to support Solidary Renewable Energy Communities. Research activities related to both topics have been carried out within the Sun4U pilot project, particularly in the Roman neighborhood of Casal Brunori. In addition to providing access to a georeferenced RSP database of nearly 200,000 buildings, the Sun4U project enabled the creation of the first REC in Rome utilizing CUGs spaces.

Importantly, the upscaling of Sun4U over the next three years foresees the provision of RSP data for the entire territory of Roma Capitale and its 15 constituent municipalities. In accordance with the municipal regulation on the use of public rooftops and PV systems, each district has received the technical and administrative competencies necessary to support the development of RECs. Furthermore, the Sun4U digital platform is currently being tested as a one-stop-shop for urban energy efficiency, with potential applications in other Italian and European urban contexts—extending the scalability and transferability of the proposed methodology.

Despite these favorable institutional and technological developments, significant barriers persist that may hinder the practical implementation of RECs in high-priority zones. Chief among these are administrative and bureaucratic constraints, particularly related to the timely allocation of publicly owned rooftops for energy projects. Additionally, there is a widespread shortage of qualified technical and administrative personnel across the 15 municipal districts, which may delay planning procedures and limit the capacity to coordinate and manage community energy initiatives effectively. These obstacles underscore the need for targeted policy interventions to strengthen local administrative capacities and streamline procedural frameworks.

Future research developments should focus on several directions. First, incorporating longitudinal and behavioral data—enabled through smart metering, IoT devices, and user engagement platforms—could enhance the responsiveness and accuracy of REC planning. Second, the integration of DTs would allow for real-time simulation and monitoring of energy flows, system performance, and user interaction, supporting predictive maintenance and adaptive management [67,68]. Third, expanding the energy model to include multi-vector solutions (e.g., combining PV with small-scale wind, storage, or biomass where appropriate) would improve system resilience and flexibility.

The study also highlights the critical role of urban policy and governance in supporting the implementation of RECs. Recognizing urban gardens as energy-relevant infrastructure in planning tools could promote multifunctional land uses that advance environmental, social, and energy-related goals simultaneously. Furthermore, the deployment of RECs will require targeted public policies, including fiscal incentives, streamlined administrative procedures, and capacity-building programs—particularly to ensure inclusion of vulnerable populations. The methodology proposed in this study contributes a robust and operational tool for supporting inclusive, sustainable RECs. It frames RECs not only as technical infrastructures for decentralized energy production but also as strategic instruments for promoting social equity, participatory governance, and climate resilience in urban settings.