Introduction 
Since the Industrial Revolution in recent centuries, urban areas have experienced rapid population growth, leading to the unsustainable consumption of fossil fuels to meet energy demands. The unprecedented global increase in energy consumption, coupled with dependency on fossil resources, has contributed to the rise in greenhouse gas concentrations in the atmosphere (Abdelaziz et al., 2011). As a result, the acceleration of global warming poses significant risks to living conditions, with substantial potential economic and social repercussions (Wąs et al., 2021). In this regard, sustainable energy systems balance energy production and consumption, ensuring that their negative environmental impacts remain within acceptable thresholds while simultaneously contributing to enhancing urban quality of life (Arasteh Talashmaki, 2020). On a global scale, considerable actions have been undertaken to address these challenges. For instance, at the 2015 United Nations Sustainable Development Summit, in support of the Paris Agreement, countries collectively underscored the importance of achieving carbon neutrality and the transition to clean energy systems (News, 2015). However, in the 21st century, large urban centers continue to confront escalating challenges, such as securing energy supplies and mitigating pollution, particularly in nations heavily reliant on fossil fuels. While renewable energy sources such as solar and wind have been proposed as sustainable alternatives, barriers such as high initial capital costs and a lack of public awareness impede widespread adoption (Torkaman & Jalilisadrabad, 2024). A literature review reveals that renewable energy has long been regarded as a crucial tool for preserving intergenerational equity in resource utilization (WCED, 1987). Studies such as those by TB et al. (1993) have focused on reducing pollution through solar and wind energy, but these studies often fail to address the social and economic dimensions of energy systems. Goldemberg (1998), with an emphasis on developing nations, highlighted the role of renewable energy in both economic and environmental development. However, the interplay among the various dimensions of sustainable development has been insufficiently explored. Drake et al. (2005) focused on technical and economic challenges but did not provide an integrated framework for understanding these issues holistically. Panwar et al. (2011) also acknowledged the role of renewable energy in mitigating greenhouse gas emissions, yet the social aspects remained largely underexplored. Karbach and Kabza (2019) underscored institutional misalignment and the weaknesses in policy frameworks. Furthermore, recent comparative studies emphasize that the successful implementation of sustainable energy policies requires the active participation of governments, communities, and the private sector (Čeryová et al., 2020; Surya et al., 2021). This crucial multi-stakeholder involvement is also reflected in the conceptual model proposed in the present study. Upon synthesizing the findings of prior research, it becomes clear that, despite significant attention to the technical, economic, and environmental aspects of renewable energy, there has been a lack of comprehensive investigation into the integration and interaction of these dimensions within a unified model. It can be concluded that most previous studies have concentrated narrowly on specific dimensions of sustainable development, neglecting the development of a cohesive and integrated model. This study aims to construct a comprehensive conceptual model for the utilization of renewable energy in urban sustainable development, employing a qualitative content analysis approach and a systematic review of the existing literature. In this context, the key research questions are as follows:
1.    What are the key dimensions and components that influence the role of renewable energy in urban sustainable development?
2.    How can the interactions between the environmental, economic, social, and institutional dimensions enhance the effective utilization of renewable energy?
3.    What conceptual model can be proposed to integrate these dimensions into sustainable energy policymaking at the urban level?
Materials and Methods
This study, aiming to elucidate the relationship between renewable energy and urban sustainable development, adopts a mixed-methods approach, which includes a systematic literature review, qualitative content analysis, and Grounded Theory. Data were collected through structured searches in domestic and international scientific databases from 2002 to 2023. Forty-two articles were selected for final analysis based on scientific and analytical criteria. The selected texts were analyzed using MAXQDA software through a three-stage coding process (open, axial, and selective), and the concepts were organized into five main dimensions (economic, social, environmental, institutional, and technological). Subsequently, by analyzing the co-occurrence and strength of the relationships between the codes, a conceptual network of indicators was extracted, and the final model of the study was designed. This model explains the causal and indirect relationships between renewable energy and urban sustainable development by identifying both strengthening and weakening factors. To validate the qualitative analysis, methods such as simultaneous coding by a second researcher, matching concepts with theoretical literature, and review by a third researcher were employed. Thus, the conceptual model derived from this study, unlike purely descriptive frameworks, has a structure based on causal analysis and has successfully illustrated, relying on documented evidence from credible articles, a meaningful network of relationships between renewable energy and various dimensions of sustainable development in urban areas.
Findings
In the first stage, the extraction and organization of indicators related to sustainable development, including “energy security,” “energy justice,” “environmental impacts,” “economic growth,” and “energy governance,” was carried out using the Grounded Theory approach. For this purpose, the texts of 48 selected articles from 2002 to 2023 were carefully analyzed, and through the use of MAXQDA, a specialized qualitative data analysis software, open coding was performed. As a result, 72 initial codes were identified as reflections of key concepts in the field of renewable energy and sustainable development. The findings of this stage are presented in Table 1 in a matrix format, which shows the presence of each code in the selected articles. In the second stage, based on the principles of axial coding, the identified codes were categorized into four main themes according to their conceptual and semantic proximities: environmental, institutional, social, and economic. Two other researchers reviewed this clustering to enhance its structural validity. Additionally, the frequency of each indicator in the examined articles and the results were presented in Table 2 to indicate the degree of attention given to each indicator. In the third stage, an analysis of the internal relationships between the indicators was conducted. Using MAXQDA software, meaningful relationships between the indicators were extracted. In Table 3, analytical propositions and the conceptual relationships between the indicators are explained, and in Figure 2, the graphical structure of these relationships is displayed. In this figure, colors and the thickness of the lines represent the type, origin, and intensity of the relationship between the indicators, respectively. In the fourth stage, the final conceptual model for the utilization of renewable energy with a sustainable development approach for urban areas was designed and presented. This model is a combination of the theoretical and empirical findings of the study and precisely illustrates the bi-directional interactions between renewable energy and the various dimensions of sustainable development. The final conceptual model is displayed in Figure 4. In this model, the indicators are divided into two categories: those that promote the increased use of renewable energy (such as energy security, pollution reduction, job creation, and access justice), which are highlighted in orange, and those that hinder the development of these energies (such as initial costs, construction time, and policy complexities), which are indicated in red. This conceptual model, while illustrating causal pathways between the environmental, social, economic, and institutional dimensions, shows that increasing the utilization of renewable energy can directly and indirectly enhance the indicators of sustainable development in metropolitan areas. In addition to its analytical value, this model serves as a tool for precise policymaking and the design of comprehensive energy development programs at both urban and trans-regional levels.
Conclusion
This study aims to fill this gap by employing a mixed-content analysis approach (qualitative and quantitative) and proposing a conceptual model based on which the indicators affecting the utilization of renewable energy and their impact on urban sustainable development have been identified and classified. The research findings reveal that these indicators can be categorized into two main groups: the first group includes indicators that contribute to the enhancement of sustainable development, such as access to energy resources, energy security, reduced consumption of fossil fuels, reduction of pollutants, job creation, social equality, energy diversity, environmental protection, economic growth, and improved quality of life. In contrast, the second group includes indicators that hinder the development of renewable energy and, consequently, reduce sustainable development, with the most significant being high initial costs, long construction times for power plants, and policy challenges. The conducted reviews show that the high initial investment costs are the primary obstacle to developing renewable energy, particularly in developing countries. Nevertheless, the analysis results indicate that the long-term benefits of utilizing renewable energy, both from an economic and environmental perspective, far outweigh its initial costs. These benefits include reducing dependence on fossil resources, improving energy security, reducing pollution-related costs, and creating opportunities for investment and entrepreneurship in underdeveloped areas. Another crucial point in the findings is the prominence of the social dimensions of renewable energy development. Unlike many previous studies, which mainly focused on economic or environmental considerations, this study shows that the equitable development of these energies can lead to an improvement in quality of life, reduce regional inequalities, and increase social participation in underprivileged areas. Examples of this include transforming remote villages into energy producers and enhancing their economic status. On the other hand, the research results emphasize that the development of renewable energy will not be possible without the involvement of governments and policymaking institutions. Financial incentives, formulating supportive laws, and facilitating investment processes are among the actions that can make the development of such energy sources smoother. The experience of developed countries has also shown that effective policies in the field of clean energy, such as preferential tariffs for small producers or public awareness programs, have been effective in increasing the social and economic acceptance of these energy sources. This study, by outlining an integrated conceptual model, demonstrates that the development of renewable energy in urban areas is influenced by a complex set of interrelated technical, economic, social, and environmental indicators. Based on this model, the most significant positive indicator is the reduction of greenhouse gas emissions and the enhancement of energy security, while the most significant barrier is the initial cost of energy production. Therefore, achieving sustainable development requires a comprehensive, interdisciplinary, and policy-oriented approach.