Determinants of Renewable Energy Technology Deployment: A Systematic Review

Abstract

Accelerating the diffusion of renewable energy requires clear evidence on which determinants enable or hinder deployment across contexts. This study aims to identify the most frequently discussed contemporary determinants of renewable energy deployment. To this end, we conduct a PRISMA-guided systematic review within the SALSA framework, complemented by VOSviewer bibliometric mapping, synthesizing 110 peer-reviewed studies published between 2013 and 2025. We group the most frequently examined determinants into eight domains (economic, environmental, energy, political, regulatory, regional, technological, and social) and summarize the prevalent direction of effect reported in the literature. Economic conditions (e.g., economic growth, financial development, green finance, and trade) and policy/regulation (e.g., institutional quality, instrument stringency, and feed-in and net-billing schemes) emerge as pivotal. Environmental co-benefits (emissions reduction and air quality improvements) and energy system factors (security and energy poverty) are influential, with context-dependent roles for fossil fuel prices and consumption. Regional context (e.g., geopolitical risk) and technological progress (eco-innovation, storage, and grid integration) shape outcomes, while public acceptance, awareness, perceived benefits/costs, and demographics condition uptake. We also document contradictory findings (e.g., foreign direct investment and oil price effects) and gaps (especially social/demographic determinants and causal evaluation of specific policies). Overall, the review offers a coherent synthesis of evidence and an actionable framework of determinants to inform policy design and investment targeting for large-scale diffusion of renewable energy technologies.

1. Introduction

Renewable energy technology (RET) has become one of the key solutions to global energy challenges, offering renewable-based alternatives to traditional fossil fuels. The deployment of renewable energy (RE) sources has drawn considerable interest with regard to climate change mitigation, environmental protection, and energy security.

Renewable technologies like wind, solar, hydropower, and geothermal energy significantly reduce ecological harm and lower greenhouse gas emissions, helping to mitigate global warming and its effects on ecosystems [1]. Moreover, renewable energy should be prioritized for more than one reason: renewable energy is first and foremost a means of meeting the Sustainable Development Goals; renewable energy is a key driver of long-term economic growth by fostering job creation and market stability [2,3]; renewable energy has significant social benefits, including improved public health, energy security and greater access to electricity in underserved communities [4]; and, last but not least, it opens the way to more efficient and resilient energy systems [5,6]. Governments have played a crucial role in promoting renewable energy, starting with the 1997 Kyoto Protocol. Since then, policy efforts have been made to decarbonize the energy sector by 2050, but policy alone is not enough to drive global adaptation in the energy sector [7].

At the same time, while renewable energy can advance multiple sustainability goals, it is not inherently sustainable. Deployment outcomes depend on siting, technology choice, governance, and distributional effects. Empirical work documents socio-environmental trade-offs and distributional tensions (e.g., land-use change, biodiversity impacts, visual/noise externalities, and uneven benefit sharing) that can produce forms of “renewable-energy injustice.” These concerns underscore that deployment determinants (institutions, policy design, financing, technology, and social acceptance) condition whether projects deliver net sustainability gains and community support. Accordingly, this review focuses on those determinants rather than presuming sustainability as an automatic outcome.

Determinants promoting renewable energy technologies (RETs), referred to as drivers, are defined as processes that shape trends and impact the achievement of set targets [8]. With this perspective, many researchers are trying to analyze the underlying processes of RET development in order to identify the factors that facilitate or hinder their progress. The literature on the determinants of renewable energy deployment has been reviewed in several major studies. Sadorsky [9,10] and Chang et al. [11] were among the first to examine the economic factors driving renewable energy adoption, emphasizing income, fossil fuel prices, and CO₂ emissions. Expanding on this, Marques et al. [12,13] analyzed energy-related and political influences in Europe, concluding that policy interventions, rather than market forces, primarily drive renewables, though economic burdens limit short-term benefits. However, the European focus of the study reduces the generalizability of the results. Darmani et al. [8] reviewed determinants of renewable energy technology development and proposed a typology; however, the scope was limited to eight European countries and specific RES. While the research provides valuable insights into RETs, its typology requires further conceptual development to be fully comprehensive [8]. Based on qualitative and quantitative research, Sener et al. [14] provide a broad categorization of determinants of RE. However, in their work, the period from 1991 to 2007 is well represented, while studies after 2010 are scarce, probably due to data availability issues [14]. This gap can be addressed by updating the data. Building on previous studies, Bourcet [15] conducted a systematic literature review focusing on the empirical determinants of renewable energy deployment at the country level. This study analyzed quantitative research to identify key factors influencing renewable energy deployment. However, certain aspects of renewable energy deployment, such as socio-demographic factors, including population characteristics and attitudes towards renewable energy technologies, have been largely ignored, but can have a significant impact on renewable energy deployment at a national level [15]. Further research on these aspects could provide valuable insights into the renewable energy deployment process. Against this background, a systematic literature review is needed to identify key patterns. To address this research gap, this article aims to better understand the factors influencing RET deployment. This study systematically reviews the literature on the determinants of renewable energy deployment, classifies the main determinants, and synthesizes an integrated set of factors that shape deployment.

Given the current goal of accelerating RET development, this knowledge is crucial to create a foundation that leverages key determinants and assesses their effectiveness across contexts. The reviewed studies examined the determinants of renewable energy technologies to identify key patterns and influences. This systematic study will help researchers identify gaps, prioritize RET deployment, and update findings through a reproducible methodology. Additionally, it contributes to and updates the existing energy economics literature by exploring the relationship between renewable energy and macroeconomic, environmental, and other energy-related determinants.

The aim of this study is to identify the most frequently discussed contemporary determinants of renewable energy deployment. This study is not limited to specific renewable energy sources or countries. The research methodology comprised two main stages: (1) searching, selecting, and preprocessing of relevant scholarly articles related to the research topic, as well as (2) applying bibliometric techniques, including the SALSA, PRISMA methods, and VOSviewer, to systematically analyze and visually map the research landscape. The findings highlight important patterns in the field, demonstrating the effectiveness of bibliometric analysis tools, particularly VOSviewer, for conducting systematic literature reviews and synthesizing knowledge.

2. Materials and Methods

This study has a two-step methodology: first, we performed a systematic literature review according to the SALSA method, providing a methodical and reproducible approach to searching, appraisal, synthesis, and analysis of relevant sources; second, using the software tool VOSviewer, a bibliometric analysis was completed to visualize co-occurrence networks, author collaboration and thematic clusters among the literature that were included in this analysis.

2.1. SALSA Framework

The SALSA method (Search, Appraisal, Synthesis, and Analysis) is used for the literature research and analysis [16,17]. This approach, often used in research [18], is based on the SALSA framework, which, according to Grant et al. [16], combines a comprehensive search process and critical review to achieve a “best evidence synthesis” [16,17]. The framework contains a “snowballing” method between the Appraisal and Synthesis steps to enable a comprehensive exploration of the literature and to reduce potential bias [17]. The PRISMA statement was also followed, ensuring consistency and comprehensiveness throughout the investigation (see Supplementary Material Table S1). The PRISMA framework is used to enhance the validity and completeness of the study [19,20].

2.2. The First Step in the SALSA System—Search

Articles for this review were identified via a systematic search of a landmark academic database, and the search was restricted to high-quality, relevant studies. Due to its early adoption, rigorous selection process, broad multidisciplinary coverage, and robust citation analysis capabilities, Web of Science (WoS) was selected as the primary database. The Web of Science (WoS) is widely acknowledged as the oldest and frequently used database of research publications and citations; with it including high-impact, peer-reviewed journals from around the globe and across all fields, it is well known to have provided reliable and quality-retrieved publications [21]. A comparative analysis by Singh et al. [22] reveals that while WoS is more selective in its journal inclusion compared to other databases, it emphasizes ensuring high-quality content. According to their findings, around 99.11% of journals indexed in WoS are also included in Scopus, highlighting WoS’s goal of having a selective list of high-quality journals. Furthermore, research on citation matching algorithms indicates that WoS performs reasonably well in tracking citation networks, supporting trend identification and research impact analysis, although it has limitations in handling inaccurate references [23]. Given these strengths, Web of Science was chosen to ensure that the study would include relevant, peer-reviewed research, while providing a comprehensive analysis of the evolution of knowledge on the deployment of renewable energy. To capture the most recent literature, at this SALSA stage, we restricted the window to 2013–2025 to reflect the contemporary era of renewable energy deployment, in which policy instruments, rapid technology cost declines, system-integration challenges, and evolving social/regulatory contexts shaped study designs and findings. Searches were executed in 2025 (March). Earlier periods featured different technologies, costs, and regulatory regimes, reducing cross-study comparability. Limiting the window, therefore, improves the relevance of conclusions to today’s policy and market conditions and to the determinant groups analyzed. The following search keywords were identified: “renewable energy,” “deployment,” “determinants,” “factors,” and “drivers,” resulting in the Boolean search string TS = (“renewable energy” AND deployment AND (determinants OR factors OR driv*)).

2.3. Appraisal—The Second Step in the SALSA System

We retrieved 1668 records from Web of Science using the Boolean string described above. At this stage, titles and abstracts were screened against predefined inclusion and exclusion criteria. We included peer-reviewed journal articles in English published in academic journals, focused on renewable energy that contained the search terms in the title, abstract, or author keywords. We excluded editorials, books and chapters, conference proceedings, meeting abstracts, and studies not related to renewable energy. After screening, 1461 records were excluded, and 207 advanced to full-text review. Backward/forward snowballing identified 14 additional records, yielding 221 full texts assessed for eligibility. Following full-text review, 111 articles were excluded (outside scope, non-empirical, no deployment outcomes, or insufficient data/reporting). In total, 110 studies met all criteria and were synthesized. A PRISMA-style flow diagram (Figure 1) summarizes the screening flow.

2.4. Extra Step: The Snowballing Technique

An extension to the SALSA system was incorporated using an additional snowballing approach to make the search more comprehensive. The snowballing technique is the process through which relevant publications are identified by reviewing the reference lists of the selected articles. This approach was especially helpful for identifying quality sources that may not have been discovered in the first search [18]. Fourteen additional publications were identified and incorporated into the dataset using this approach (Figure 1).

2.5. General Characteristics of Included Studies

Based on the content analysis, a total of 110 publications were selected. To understand the disciplinary focus, we used Clarivate’s Web of Science “Citation Topics” taxonomy (Analyze Results → Citation Topics; Micro/Meso) applied to our included-record set. At the micro level, the majority (74.5%) of publications were classified under the Environmental Kuznets Curve (EKC) topic, while 14.5% were categorized under Renewable Energy, which indicates that research on renewable energy deployment tends to be placed in a broader economic–environmental framework rather than treated as a distinct topic. At the meso level, the dominant thematic classification was Sustainability Science, which accounted for 89.1% of the publications and represented the overarching environmental and socio-economic context of the reviewed literature. Moreover, an indexation evaluation indicated that 79.1% of the publications were indexed in the Social Sciences Citation Index (SSCI), and 72.7% in the Science Citation Index Expanded (SCI-EXPANDED), thus confirming the academic quality and interdisciplinary aspects of the literature under review. Further analysis of the research areas related to the publications confirmed that the sample is made up of areas closely related to renewable energy research. Almost half of these (48.2%) were in the field of Energy Fuels, 44.5% in the field of Environmental Sciences Ecology, and 26.4% in the field of Business Economics. Other important research areas were Science Technology Other Topics (36.4%) and Thermodynamics (6.4%).

2.6. Synthesize: The Third Step of the SALSA System

During the synthesis stage, the findings of selected publications were structured and summarized into thematic groups to identify the key determinants influencing renewable energy technology implementation. Since deployment is not shaped by a single type of factor but by a complex interplay of economic viability, environmental benefits, energy system characteristics, political priorities, regulatory frameworks, regional contexts, technological maturity, and social acceptance, the studies reviewed were grouped into the following categories: economic, environmental, energy, political, regulatory, regional, technological, and social factors. The eight categories capture the main domains most frequently highlighted in the literature, ranging from economic viability and technological maturity to social acceptance and regulatory frameworks, and are consistent with established classifications used in previous systematic reviews and policy reports. These categories reflect the holistic and interdisciplinary drivers of renewable energy deployment and provide a systematic framework for integrating diverse findings rather than leaving them fragmented. The aim of this phase was to synthesize the evidence and provide a structured overview of the drivers of renewable energy deployment, which would provide a clear basis for the next phase of analysis.

2.7. Analysis: The Fourth Step of the SALSA System

In the analysis phase, the determinants identified in the synthesis phase were examined to clarify their relationships, differences, and interactions in various economic, political, and regional contexts. The analysis summarizes the determinants’ reported direction of effects in the literature and discusses contradictions and contextual nuances. This step was aimed at clarifying how these factors cumulatively determine the use of renewable energy and was based on the interpretation of the results presented in the following sections.

2.8. VOSviewer

VOSviewer co-occurrence mapping (all keywords; full counting; min-occurrence = 2) was applied. Of 577 keywords, 188 met the threshold and were retained (selection by total link strength, TLS). A sensitivity run at min-occurrence = 3 preserved the cluster structure and the leading high-TLS terms. Pre-processing: No custom synonym consolidation or stemming, with VOSviewer default stop-word handling only. Normalization: Association strength (default). Clustering: VOS clustering (default resolution). Layout: Default VOSviewer layout (visualization only; does not affect cluster membership). Maps were generated in VOSviewer v1.6.20 from a Web of Science export (Full Record and Cited References). Cluster-level results are reported in the Section 3.

VOSviewer is a commonly used software tool for constructing and visualizing bibliometric networks. It enables the construction of networks (co-authorship, citation, and keyword co-occurrence) that reveal the structure and evolution of research fields. Its effectiveness has been recognized in numerous academic studies. Kirby [24] highlights its role in exploratory bibliometrics, showing how open source tools improve preliminary literature analysis and point to directions for future research. Similarly, Van Eck and Waltman [25] discuss the use of VOSviewer to cluster scientific publications, which helps to better understand research areas. In addition, another of their studies highlights the ability to process and visualize detailed bibliometric data using text mining techniques, as well as to improve understanding of academic trends [26]. This analysis provides a comprehensive bibliometric evaluation of the drivers of renewable energy uptake deploying VOSviewer. Adding this analytical framework strengthens the research in two major respects:

(1)

Enhancing literature analysis with bibliometric mapping. Traditional review methodologies often rely on qualitative synthesis, which can lead to macro-level trends being missed. Using VOSviewer, this study takes a systematic approach to map out research trends, contributions, and emerging themes in the field of renewable energy deployment. This visualization step allows for a structured analysis of the academic discourse and a more detailed identification of knowledge clusters and research frontiers.

(2)

Integrating quantitative and qualitative approaches. Combining bibliometric analysis with traditional review methods increases the comprehensiveness and acceptability of results. The network visualization developed by VOSviewer allows for an intuitive exploration of the interrelationships between economic, environmental, energy, technological, political, regulatory, regional, and social factors influencing the deployment of renewable energy. This interdisciplinary perspective provides a clearer picture of the evolving landscape in this field.

Within this framework, the study contributes to existing literature in several ways: (1) the bibliometric analysis informs readers, using data, about the evolution of renewable energy adoption studies; (2) a comprehensive synthesis of key determinants, including economic, environmental, energy, technological, policy, regulatory, regional, and social factors, provides a multidimensional perspective and addresses key gaps in previous research; and (3) as the field of renewable energy technology deployment continues to expand, a bibliometric review at this stage enables scholars to better understand dominant themes and to identify underexplored areas for further investigation.

We classify key determinants into a conceptual framework and, using bibliometric visualization, map the field to highlight research priorities for accelerating renewable energy uptake.

3. Results

Our analysis draws on a broad empirical literature across regions and economic contexts. Using keyword co-occurrence, citation networks, and clustering, we provide a data-driven, multidimensional view of how determinants shape the renewable energy transition. A SALSA-guided review synthesizes 110 peer-reviewed articles (2013–2025). Each study focuses on different historical periods, starting in 1970 and ending with projections up to 2045. The number of countries analyzed in the studies ranges from 1 (single-country studies) to 175 (broad global studies), including OECD countries, EU countries, MENA countries, South Asian countries, Sub-Saharan African countries, and ASEAN countries (Figure 2). Global coverage was applied in 25% of studies (n = 27) between 1970 and 2021. Other studies focus specifically on OECD countries (n = 11, 10% of studies) and cover a long period of time, from 1970 to 2022. In addition, some studies cover a longer period of time, such as more than 40 years, and show an interest in long-term energy transitions in developed economies. Further studies cover EU countries (n = 11, 10% of studies) between 1980 and 2021. Most of the studies cover the 1990s and 2000s, reflecting the interest in EU policies at the start of the Kyoto Protocol and the Paris Agreement. China is the next largest group (n = 9, 8% of studies), with studies mostly covering the period 1994–2022, reflecting the increasing focus on China’s transition to renewable energy and its role as a key player in global energy markets. Studies of developing regions (MENA countries (n = 3, 3% of studies, between 1984 and 2020)), South Asian countries (n = 3, 3% of studies, between 1990 and 2021), Sub-Saharan African countries (n = 3, 3% of studies, between 1995 and 2020), and ASEAN countries (n = 2, 2% of studies, between 1975 and 2022) show an increasing, but still limited, focus on renewable energies. Other (n = 41) studies cover individual countries, including Pakistan, Malaysia, Japan, Greece, India, Kenya, Poland, Thailand, Tunisia, Ghana, France, Finland, Argentina, South Korea, and Uzbekistan.

According to research by Darmani et al. [8], Sener et al. [14], and Bourcet [15], different categories of potential determinants of renewable deployment can be identified. Based on the framework of categories and sub-categories of determinants of renewable energy deployment collected in their studies [8,14,15], we have categorized the determinants explaining renewable energy deployment into economic, environmental, energy, political, regulatory, regional, technological, and social. We have divided the main categories into 262 subcategories.

Table 1. Determinants explaining the deployment of renewable energy.

Economic Determinants	Frequency	Environmental Determinants	Frequency	Regulatory Determinants	Frequency
Economic Growth	33	CO2 Emissions	23	Kyoto Protocol	2
Fossil Fuel Prices	2	Environmental Degradation	2	Environmental Policy Stringency	2
Energy Prices	1	Environmental Quality	1	Net-Metering/Net-Billing Programs	1
Real Oil Prices	7	Mitigation of Air and Other Pollutants	2	Feed-In Tariffs	1
Financial Development	10	Energy Determinants	Frequency	Environmental Taxes	2
Foreign Direct Investment	6	Energy Consumption	3	Energy Taxes	1
Domestic Investment	1	Energy Productivity	1	Natural Resource Rents	1
Green Finance	5	Fossil Fuel Consumption	2	Carbon Tax Policy	1
Trade Openness	6	Energy Poverty	4	Regional Determinants	Frequency
Climate-Resilient Economy	2	Energy Security	4	Geopolitical Risk	7
Economic Complexity	2	Fossil Fuel Industry Lobbying	1	Natural Resources	3
Economic Globalization	3	Traditional Energy Sources	1	Spatial Spillovers	1
Shadow Economy	1	Political Determinants	Frequency	Geographical Factors	1
Employment and Job Creation	4	Institutional Quality	4	Technological Determinants	Frequency
Social Equity	1	Governance Quality	2	Eco-Innovation	2
Human Capital	2	Political Stability	2	Technological Progress and Innovations	5
Human Development	2	Democratic Institutions	2
Income Inequality	2	Policy Effectiveness	1
		Political Risk	1
Social Determinants
	Frequency		Frequency		Frequency
Environmental Concern	8	High Costs of RE	2	Non-involvement in Decision-Making	2
Environmentally Responsible Behaviors	2	Initial Costs of RE	1	Subjective Well-Being	1
Value Orientation	1	Financial Incentives of RE	2	Life Expectancy	3
Impact on Biodiversity	1	Ease of Use of RE	2	Public Health	4
Renewable Energy Awareness	5	Risk/Trust for RE	3	Health Expenditures	2
Environmental Awareness	1	Employment and Job Creation	1	Education and Highly Educated Individuals	4
Lack of RE Awareness	1	Ownership (public vs. private)	1	Individual Income Level	4
Preferences for RE	3	Distance and Visibility	1	Age-related Attitudinal Differences	2
Perceived Benefits of RE	6	Perception of Neighbors’ Participation	2	Gender	2
Utilitarian Benefits of RE	1	Collectivism	1	Marital Status	1
Relative Advantage of RE	2	Trust in Institutions	1	Urbanization	3
Renewable Energy Costs	2	Mistrust of the Central Government	1	Urban Population	1
Low Cost of RE	1	Perceived Self-Efficacy	4	Population Growth	1

summarizes how frequently each subcategory is emphasized in the main manuscripts.

Within the category of economic determinants, the sub-categories most frequently mentioned in research papers are the following: economic growth (33 mentions), financial development (10 mentions), and real oil prices (7 mentions). Regarding environmental determinants, the most frequently mentioned sub-category is CO₂ emissions (23 mentions). Within the energy determinants category, the most frequently mentioned sub-categories are as follows: energy security (four mentions), energy poverty (four mentions), and energy consumption (three mentions). In the category of political and regulatory determinants, the most frequently mentioned sub-categories are as follows: institutional quality (four mentions), the Kyoto Protocol (two mentions), policy stringency (two mentions), and environmental taxes (two mentions). Regarding regional determinants, the most frequently mentioned sub-category is geopolitical risk (seven mentions). Regarding technological determinants, the most frequently mentioned sub-category is technological progress and innovation (five mentions). Finally, for social determinants, the following sub-categories are frequently mentioned: concern for the environment (eight mentions), perceived benefits of renewable energy (six mentions), awareness of renewable energy (five mentions), perceived self-efficacy (four mentions), health of the public (four mentions), education (four mentions), and income level of the individual (four mentions).

Additional work has also been carried out with a bibliometric analysis conducted using VOSviewer to explore knowledge structures within this field. The keyword co-occurrence analysis confirmed that topics related to the deployment of renewable energy include economic (e.g., investment and energy costs), environmental (e.g., emissions and sustainability), energy (e.g., energy insecurity and poverty), political (e.g., government stability), regulatory (e.g., incentives), regional (e.g., natural resources and geopolitical risk), technological (e.g., innovation and efficiency), and social factors (public acceptance and social behavior) were also very prominent. The themes that co-occurred portray the multifaceted scope of renewable energy deployment research, which is affected by financial, environmental, technical, social, political, as well as regulatory factors. Below, we examine in more detail the sub-categories of determinants presented in Table 1, considering the papers that take them into account and their estimated impact on renewable energy deployment.

3.1. Economic Determinants

Economic determinants are key to the deployment of renewable energy technologies. The viability and speed of uptake of renewable energy depend directly on financial resources, market conditions, investment incentives, and wider economic structures. Trade policies, energy prices, and financial markets can help or hinder the transition to renewables, and a growing economy can stimulate investment in clean energy infrastructure. Key economic factors, including economic growth, energy and oil prices, financial development, investment, green finance, trade openness, economic dynamics, employment, socio-economic field, human capital, and development, are investigated in this part (Figure 3). The analysis of these elements provides a better understanding of how the economic situation affects the deployment of renewable energy.

3.1.1. Economic Growth

The integration of renewable energy is greatly influenced by economic growth. Research shows that the relationship between economic growth and the consumption of renewable energy is strongly interrelated, suggesting that both variables have a reinforcing effect on each other in the short run and the long run [27,28]. Many studies in different settings from around the world validate the assertion that economic growth is a fundamental driver for the adoption of renewable energy, as it is widely known that a stronger economy not only improves investment opportunities in renewables but also increases the prospects of using sustainable energy [29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50]. Economic growth, indeed, produced 30 positive and 2 negative findings, which only serve to attest to the great effect it has on renewable energy adoption. However, the strength of this relationship varies across country classifications. On the one hand, the deployment of renewable energy in high and middle-income nations is greatly improved by economic growth [51]. On the other hand, in low-income countries, the relationship is often statistically insignificant, likely due to financial constraints and limited access to technology [51]. Additionally, political institutions influence this dynamic. In rich democracies, their economic growth supports renewables, while in poorer, less democratic countries, economic growth is “cheaper” when built on fossil fuels [52,53].

3.1.2. Energy Prices and Oil Prices

Within the context of our research, we found four positive findings concerning real oil prices confirmed by research that increases in oil prices serve as a catalyst for renewable energy deployment [28,47,51,53,54]. Nonetheless, this correlation is rather sensitive to the economic profile of the country. Omri and Nguyen [51] discovered that in middle-income countries, increasing oil prices have a detrimental effect on the consumption of renewable energy owing to the dependency on fossil fuels and high economic sensitivity to other external factors. On the other hand, higher-income countries were found to be insignificantly affected, which could stem from a wider set of available energy options and a stronger economy. In addition, Chen et al. [53] distinguished this relationship in the political context and argued that in less democratic countries, renewable energy consumption increased in response to higher real oil prices, whereas in democratic countries, there was no change. Other research indicates that the costs of fossil fuels greatly determine the utilization of renewable energy sources, but differ from one region to another and one economic situation to another. The works of Apergis and Payne [27] demonstrated how a policy change that took place in Central America in 2002 reinforced the pre-existing relationship between renewable energy and fossil fuel prices, thereby increasing the economic sensitivity of the region to carbon emissions. Yet, contrary to other works, Aguirre and Ibikunle [55] noticed fossil fuel prices did not significantly explain the growth in the consumption of renewables. Li et al. [39] confirmed that energy prices are a prerequisite for renewing energy consumption, supporting the idea that increasing expenditures on conventional energy fuels the movement toward renewable alternatives.

3.1.3. Financial Development

The adoption of renewable energy resources can be facilitated by financial development. Shahbaz et al. [43], Mohamed Yusoff et al. [46], Ngcobo and De Wet [48], Li et al. [49], Anton & Nucu [56], Le et al. [57], and Awijen et al. [58] found that well-developed financial markets in high-income countries support investments into renewable energy resources. Our results align with this perspective, as financial development demonstrates seven distinct positive effects. In regions with sophisticated financial systems, there is a strong institutional support for renewable energy financing through green bonds, capital market instruments, and backing from the banking sector. Unfortunately, less developed financial infrastructures in low- and middle-income countries dampen the impact of financial development [57]. Not all economic relationships with financial development leading to renewable energy adoption are positive. Saadaoui & Chtourou [59] assert that in Tunisia, financial development leads to reduced adoption of renewable energy, which in turn shows an imbalance that needs sustainable financial policies aimed towards curtailing growth in unneeded areas while directing to green energy objectives. Osman et al. [60] also argue that there is a negative impact of financial development on the consumption of renewable energy in Sub-Saharan Africa because of a lack of proper financing structures and green financing instruments.

3.1.4. Foreign Direct Investment (FDI) and Domestic Investment

Foreign direct investment (FDI) presents both opportunities and challenges for renewable energy deployment. In some developing countries, FDI has had a definite impact on harnessing renewable resources [41,42,43,61,62,63]. We have found four positive findings supporting these claims. Opposition research suggests that FDI can lock in fossil fuel dependence in some areas, especially where fossil fuel energy is relatively cheap [40,46]. This explains the two negative findings for FDI in our study. The research of Mohamed Yusoff et al. [46] points out that, unlike FDI, domestic investment does increase the share of renewable energy in Malaysia. This implies that in some areas, domestic investments may be more helpful than FDI in advancing renewables.

3.1.5. Green Finance

The deployment of renewable energy sources was found to be driven by green finance, which was found to have five positive impacts without any negative impacts. Green finance is critical to supporting investments in renewable energy, as well as facilitating economic development in developing countries [64]. In Chen et al.’s [64] research, green bonds, carbon markets, and investments in renewable energy were shown to have integrative impacts, thus defining the scope of green finance. The studies [65,66,67] also confirm that green finance encourages investment in renewable energy technologies where there is developed financial infrastructure. Sampene et al. [50] also note the contribution of green finance to the renewable energy transition in E7 countries, underscoring its importance to the world. This was further reinforced by Du et al. [67], who, in their research, analyzed the influence of governance on the effectiveness of green finance. Such findings consolidate the argument that green finance is only effective when coupled with transparent regulatory environments and strong financial institutions.

3.1.6. Trade Openness

The relationship between trade openness and the adoption of renewable energy is intricate. Its impacts are both positive and negative, showing two and three results, respectively. As Alam and Murad [36] as well as Omri and Nguyen [51] explained, trade openness fosters the growth of renewable energy usage in countries that are economically stable. On the contrary, Chen et al. [53] discovered that trade openness did not have a strong impact on renewable energy consumption in democratic countries, while in less democratic countries, it had a negative impact. This supports the results of Kang et al. [40], along with Mohamed Yusoff et al. [46], who also noted a negative impact of trade openness on renewable energy adoption in South Asian countries and Malaysia, respectively.

3.1.7. Climate-Resilient Economy

Hao and Shao [68] undertook the analysis on the implementation of renewable energy in 118 countries and found that countries suffering from climate change or having low-carbon economies are more likely to adopt renewable energy, especially with strong policy support. This demonstrates the strategic movement toward sustainability. Hao [69] investigated the renewable energy usage of USA states from 1997 to 2019 and discovered that those with low carbon intensity and high climate effects use more renewables. It was noted within the study that the implementation of renewable portfolio standards was beneficial for adoption, underlining the influence of economic structure and policies on sustainable energy shifts.

3.1.8. Economic Complexity and Globalization

Economic complexity had two negative findings, supporting the evidence that complex economies face challenges in transitioning to renewable energy due to established fossil fuel-dependent industries [44,54]. The reverse is true when the renewable energy industry begins to mature; these barriers fade over time. By contrast, the two positive outcomes of economic globalization are contradictory. Globalization is said to stimulate the growth of renewable energy in some contexts [45,70] while in others, it is said to create a volatile market which is detrimental to long-term investments in renewable energy [71].

3.1.9. Shadow Economy

The shadow economy poses new challenges in the adoption of renewable energy by introducing informal energy markets and weakening regulatory control over such activities. Research by Chu et al. [54] asserted that in most high-income and middle-income countries, the existence of sizable shadow economies adversely impacts the deployment of renewable energy by siphoning funds away from genuine investment channels. Furthermore, stringent policies aimed at protecting the environment tend to be counteracted by uncontrolled segments that continue to heavily depend on fossil fuels. While some studies support the notion that strong institutional governance aimed at reducing the shadow economy can increase renewable energy investments, others suggest that informal economies can provide greater energy access in poorer regions. But these informal economies do not provide a sustainable long-term energy model.

3.1.10. Employment and Job Creation

Our findings indicate four positive effects of employment and job creation, which are supported by the evidence that renewable energy industries tend to create more jobs than fossil fuel industries [72,73,74,75]. It is reported that jobs in renewable energy are easier to automate, resulting in better job retention in the long term.

3.1.11. Human Capital and Human Development

The studies [39,76] confirm that human capital is an important factor in the adoption of renewable energy. These researchers established a notable relationship between human capital and the adoption of renewable energy. Sasmaz et al. [77] and Adekoya et al. [78] show that higher levels of human development imply greater consumption of renewable energy, although the effect differs by region.

3.1.12. Improvements in Social Equity

The role of the social equity gap discussed in the context of renewable energy has been well covered, with considerable evidence that an effective approach contributes to the decrease in socioeconomic gaps. Our research gives one positive result related to social equity conversation, which confirms the works of Fraser, Chapman, and Shigetomi [79].

3.1.13. Income Inequality

The link between renewable energy and income inequality is multifaceted, with the literature reporting both adverse and positive impacts. Apergis [80] noted that increased production of renewable energy, especially solar energy, is associated with greater income inequality in OECD countries. In particular, investment activity is concentrated among incentive-receiving groups; therefore, financial renewables’ support structure aids the wealthy. In this scenario, without effective policy actions, the renewable energy transition would likely deepen economic divides. On the other hand, Topcu and Tugcu [81] claim that the adoption of renewables aids in decreasing income disparity by lowering energy expenditure for low-income families and enabling more even wealth distribution.

3.2. Environmental Determinants

The application of renewable energy technology is much shaped by environmental determinants. The switch to renewable energy is mainly driven by the need to slow climate change, reduce greenhouse gas (GHG) emissions, and improve overall environmental quality. Renewable energy sources, including wind, solar, and hydropower, are prominent in global climate plans as they are well known for reducing CO₂ emissions and thus reducing dependence on fossil fuels. This section looks at how environmental issues are affecting the global transition to clean energy, highlighting the links between renewable energy and CO₂ emissions, air quality improvements, and other environmental benefits (Figure 4).

3.2.1. CO₂ Emissions

The correlation of renewable energy consumption and reduced CO₂ emissions has been well documented in the literature. The research studies [27,28,31,32,51,52,55,82,83,84,85] show that there is a strong correlation between consuming renewable energy and reducing CO₂ emissions around the world. Our analysis verifies this with 21 positive findings and only 2 insignificant impacts, confirming that renewables are vital in the combat of carbon emissions. The results above also suggest that this effect is likely to be the greatest in high-income countries [54], where policies and technologies facilitate a more seamless shift towards clean energy. Middle-income countries, on the other hand, do not show any significant relationship between renewable energy consumption and CO₂ emissions, indicating that there are some economic and infrastructural constraints [54]. Regionally, studies confirm that renewable energy sources play a considerable role in the decline of carbon emissions in Central America [27], Argentina [86], Japan [87], South Asia [32,40,53], China [88,89], the EU [82], MENA [49], as well as G7 and OECD countries [28,90,91].

3.2.2. Environmental Quality, Environmental Degradation, and Air Pollution Mitigation

Renewable energy not only reduces emissions but also provides greater environmental benefits. The graph indicates one positive finding for environmental quality, two positive findings for environmental degradation, and two positive findings for the mitigation of air and other pollutants. This is supported by studies highlighting the importance of renewable energy for air quality [49,92,93,94,95]. According to Dogan and Pata [93], the use of renewable energy together with investment in ICT and R&D in the G7 countries results in an appreciable enhancement of environmental quality. Similarly, Ilyas et al. [94] and Sun et al. [95] highlight the role of renewable energy in mitigating environmental degradation in Southeast Asia and G7 nations, respectively. These studies emphasize the dual benefits of renewable energy, demonstrating its ability to improve both environmental and economic sustainability. Koengkan et al. [92] illustrate that the more renewable energy is consumed in the 19 countries in Latin America and the Caribbean, the lesser the pollution and healthier the air would be. Li et al. [49] suggest that if Los Angeles changed to 100 percent renewable electricity by 2045, the city would have a drastic reduction in harmful pollutants such as nitrogen oxides and fine particulate matter.

3.3. Energy Determinants

Energy-related determinants also have a major impact on the deployment of renewable energy technologies. At the national and international level, energy transitions are driven by the interplay between energy consumption patterns, energy security issues, dependence on fossil fuels, and the acceptance of renewable energy sources. Some energy factors, such as energy efficiency and energy security, are driving the development of renewables, while others, such as traditional energy sources and the fossil fuel lobby, are major barriers to their development. This section examines the main energy factors affecting the deployment of renewable energy: energy consumption and productivity, energy poverty, energy security, the impact of traditional energy sources, and the fossil fuel lobby (Figure 5). Analyzing these elements helps to understand the complex relationship between conventional and renewable energy systems and the challenges faced in the transition to a sustainable energy future.

3.3.1. Energy Consumption and Energy Productivity

The graph illustrates how energy consumption and productivity influence the adoption of renewables in comparison with other variables, which partially follows the works [39,43,55,63,76]. It is worth noting that the main variables examined had both positive and negative effects. For instance, energy consumption had two positive impacts and one negative impact, while energy productivity had one positive impact. The consumption of fossil fuels resulted in one positive and one negative outcome. Akintande et al. [76] found that energy use and electricity consumption are important determinants of renewable energy deployment in Africa’s most populous countries. Likewise, Hoa et al. [63] found that the consumption of fossil fuels does negatively impact the adoption of renewables; however, in East Asian countries, the consumption of electricity does positively impact the uptake of renewables. On the other hand, Aguirre and Ibikunle [55] observed a negative correlation between increased energy consumption and renewable energy participation, suggesting that countries prioritizing energy security often turn to fossil fuels for economic advantage. Shahbaz et al. [43] concluded that fossil fuel consumption can have a positive impact on the use of renewables, highlighting the complex interactions between conventional and renewable energy sources. This reasoning coincides with that provided by the graph, which simultaneously describes the positive and negative outcomes of the consumption of fossil fuels. The duality expressed in Figure 5 demonstrates the lingering conflict between dependence on fossil fuels and the global desire to undergo an energy shift. To conclude, Li and his colleagues [39] stated that energy productivity is of great importance in determining the consumption of renewables in the member states of OECD, which underlines the role that energy efficiency plays in the use of renewables.

3.3.2. Energy Poverty

Our study shows that there are four positive impacts of renewable energy on energy poverty, which confirms that renewable energy plays a crucial role in reducing energy poverty, as highlighted by Lee et al. [96], Zhao et al. [97], Haldar et al. [98], and Chien et al. [99]. Lee et al. [96] and Wang et al. [71] discussed how renewable energy technology innovation (RETI) decreases energy poverty, especially in China. Zhao et al. [97] have observed the transition from classic non-renewable energy sources to renewable sources and noted how this transition improves and alleviates energy poverty, especially in Europe, where pro-efficiency energy use policies are being adopted. The positive impact of energy poverty shown in Figure 5 also confirms the study by Haldar et al. [98]. They found that renewable energy initially increases poverty and eventually reduces it, particularly in Sub-Saharan Africa, highlighting the role of governance and institutional support. Chien et al.’s [99] notation on the major pillar of renewable energy states that the practice of sustainable energy practices, the utilization of natural resources, and proper waste management in South Asia emphasize that renewables are indeed the solution to energy poverty.

3.3.3. Energy Security

The evidence indicates that ensuring energy security is one of the key motivators for the use of alternative energy resources, which is in agreement with findings from Chu [44], Chu et al. [54], and Wang et al. [88]. In our case, there was one insignificant effect and three positive outcomes. These studies highlight that renewable energy development is driven by concerns about energy independence and geopolitical risks. Energy security receives a high positive impact, which supports Wang et al. [88], who, in their study, noted a strong relationship between energy security and the adoption of renewables in China, stressing the influence of strong policies that perpetuate this shift. According to Chu et al. [54], a country’s energy security always pushes major energy consumers to renewables, which corroborates the evidence presented in Figure 5. Chu [44] also examines the G7 nations and demonstrates that energy insecurity drives the use of renewable technologies, although to different extents depending on the amount of renewable energy already in place. These findings, however, are contested by Aguirre and Ibikunle [55], arguing that there is a lack of evidence suggesting that considerations for energy security significantly determine participation in renewable energy.

3.3.4. Traditional Energy Sources and Fossil Fuel Lobbying

Our analysis reveals a negative correlation between traditional energy sources, fossil fuel lobbying, and renewable energy participation. Renewable energy cannot be adopted while traditional energy sources are relied upon due to the influence of the fossil fuel lobby, as noted by Aguirre and Ibikunle [55]. The enduring lobbies of traditional energy sources are a prominent impediment to the uptake of renewables. Our results also confirm previous findings that fossil fuels both encourage and discourage the use of renewable energy sources. This complexity is in line with Aguirre and Ibikunle [55], who pointed out that the fossil fuel lobby is a major barrier to the growth of renewable energy markets. The strong negative correlation between traditional energy sources and renewable energy participation highlights the entrenched power of the fossil fuel industry and its continued resistance to the clean energy transition.

3.4. Political Determinants

Political factors also play a crucial role in shaping the deployment of renewable energy technologies. Strong institutions, stable governance, and effective policies create a favorable environment for long-term investment in renewable energy. Conversely, political instability, weak institutional frameworks, and ineffective policies can hinder the transition to clean energy by creating uncertainty and discouraging investment. This chapter examines the main policy factors that influence renewable energy deployment, including institutional quality, political risk and policy effectiveness, governance quality, and political stability, and the role of democratic institutions (Figure 6). Understanding these factors is essential for policy makers seeking to establish stable and supportive regulatory frameworks to accelerate the transition to sustainable energy.

3.4.1. Institutional Quality, Political Risk, and Policy Effectiveness

According to Figure 6, institutional quality (four positive findings) has the most favorable influence among political determinants. This is consistent with the results of Bhattacharya et al. [31], Uzar [52], Saadaoui & Chtourou [59], and Wang et al. [71], which note the role of strong institutions in the adoption of renewable energy. The control of corruption, government stability, and the rule of law creates the possibility for sustainable energy policies to be implemented. On the other hand, the negative influence of political risk shown in Figure 6 supports the argument that, in most cases, political instability has a negative impact on the investment of long-term renewable energy projects [71]. Furthermore, the analysis of policy effectiveness measures showed that participation in renewables was lower than expected. This implies that some of the policies most frequently used, especially those which are vague and discontinuous, tend to limit investment in the sector [55].

3.4.2. Governance Quality and Political Stability

The variables of quality of political governance and political stability, as shown in Figure 6, also have a significant positive effect, confirming the studies by Awijen et al. [58] and Berrich et al. [100]. These aspects are fundamental in creating favorable conditions from a political and economic perspective to develop renewable investment. Such findings validate the hypothesis that governance quality leads to the effectiveness of regulation, wherein there is less ambiguity for investors, thus encouraging renewable energy initiatives. On the other hand, inadequate governance systems constitute an obstruction to the efficient energy transition strategy execution.

3.4.3. Democratic Institutions

Figure 6 shows that democratic institutions also have a strong positive impact on the deployment of renewable energy, which confirms the studies of Chen et al. [53] and Aklin [101]. Countries with a functioning democracy usually have clearer and easier-to-implement policies that encourage longer-term investment in clean energy. Democratic accountability results in forced continuity of policies, which lowers the risk for investors facing extreme regulatory shifts. Non-democratic regimes, on the other hand, mostly focus on short-term economic objectives, which leads to a dominance of fossil fuels over renewables.

3.5. Regulatory Determinants

Regulatory frameworks play a key role in shaping the deployment of renewable energy technologies. Well-designed policies and international agreements can accelerate the transition to clean energy. And vice versa, ineffective or poorly implemented regulations can slow progress. The effectiveness of regulatory mechanisms often depends on their design, implementation, and the wider economic and political context in which they operate. This chapter examines the main regulatory factors that influence the deployment of renewable energy, including international agreements such as the Kyoto Protocol, the stringency of environmental policies, and specific policy instruments such as net energy calculation, feed-in tariffs, energy and environmental taxes, Natural Resource Rents, and carbon tax policies (Figure 7). By analyzing these regulatory factors, we can better understand their role in promoting or hindering the global transition to sustainable energy.

3.5.1. Kyoto Protocol

The Kyoto Protocol shows a strong positive impact on renewable energy deployment. This is consistent with Aguirre and Ibikunle [55], who discovered that the Kyoto Protocol signatories’ investment in renewables sharply increased. Similarly, Miyamoto and Takeuchi [102] also confirm that the protocol acted as the impetus for the international spread of renewable energy technologies, reinforcing its role as a major driver of climate policy.

3.5.2. Environmental Policy Stringency

Figure 7 demonstrates a positive effect of highly restrictive environmental policies. This corroborates with Godawska and Wyrobek [103], who observed that environmental policies in Central European countries positively stimulated the production of renewable energy. Likewise, Chu et al. [54] found that G7 countries had a favorable transition to new energy technologies because of the strict environmental policies, which indicates that these nations had effective policy measures in place for such transitions to occur.

3.5.3. Net-Metering/Net-Billing Programs, Feed-In Tariffs, Energy and Environmental Taxes, Natural Resource Rents, and Carbon Tax Policy

According to Kersey et al. [104], effective policies such as net metering and feed-in tariffs have a positive impact, as shown in Figure 7, by contributing to the increase in the deployment of solar PV on 31 Caribbean islands. Energy and Environmental Taxes are more complex as they have both positive and negative effects, as shown by Dogan et al. [47], who found negative impacts within the EU, and Sun et al. [95], who found positive impacts within the G7. This indicates the possibility that environmental tax effectiveness may rely on the respective region’s policies and economic structures. The negative effect of the Natural Resource Rents aligns with Zhao et al. [45], who claimed that states with economies driven by resource extraction struggle to shift towards adopting renewable energy. The Carbon Tax Policy’s effect being insignificant aligns with the ideas of Hao and Shao [68], which state that carbon tax policies had no substantial impact on renewable energy use within 118 countries. This shows that there are other economic and regulatory factors that determine the deployment of renewable energy that are more important.

3.6. Regional Determinants

The deployment of renewable energy technology is much shaped by regional determinants since geographical location, natural resource availability, and geopolitical conditions affect the feasibility and attractiveness of clean energy investments. The interplay between geopolitical risks, natural resource distribution, and spatial spillovers determines how different regions make the transition to renewable energy: some regions have strategic advantages while others face structural barriers. This part investigates the main regional variables of renewable energy adoption, focusing on geopolitical risks and conflicts, natural resource distribution, and geographic and spatial factors (Figure 8). Understanding these regional differences helps to explain why different countries and economic environments are moving towards renewable energy at different rates.

3.6.1. Geopolitical Conflicts and Geopolitical Risk

Our results indicate that geopolitical risk has positive and negative influences on the adoption of renewable energy, which supports the position held by Su et al. [105] that there is an interdependence between these regions. On the one hand, risk impacts the adoption of renewable energy due to the concern over energy security, the competition for scarce metals, and trade wars. But on the other hand, the expansion of renewable energy impacts geopolitical risk in terms of global economic growth, fossil fuels, and technological innovation. Further supporting this conclusion, Sweidan [106] observes a strong positive relationship between renewable energy deployment in the USA and geopolitical risk. Geopolitical risk, having a positive influence, as noted in some areas, is consistent with the works of Chu et al. [54] and Cheikh & Zaied [107], which indicate a positive correlation between high-income nations undergoing energy transition due to geopolitical conflicts. However, this is not the case for middle-income countries, where geopolitical risks hinder the deployment of renewable energy, demonstrating that economic prosperity has an impact on energy transitions [54]. Moreover, the negative impacts observed in other regions are in line with the findings of Sun et al. [95] and Zhao et al. [45], which argue that geopolitical risks hinder the deployment of renewable energy in G7 and OECD countries, most likely due to the increased uncertainty and indecision associated with policy changes.

3.6.2. Natural Resources, Spatial Spillovers, and Geographical Factors

Our results show two positive effects of natural resources on renewable energy deployment in certain contexts, as reported by Ahmadov & Van Der Borg [108] and Han et al. [109]. These studies have noted that developed countries are more willing to invest in renewable energy because of their resources. In contrast, Han et al. [109] argue that while the abundance of natural resources is associated with a delay in fossil fuel divestment, there is some evidence that revenues from these resources can be used to invest in renewable energy, and that economically sustainable growth can be realized in the oil-producing countries. However, this is not uniform across regions. In Sub-Saharan Africa, natural resources tend to negatively impact renewable energy consumption, suggesting that resource wealth does not always translate into sustainable energy investments [60]. This is in line with Ahmadov & Van Der Borg [108], who pointed out that oil and gas wealth tends to undermine renewable investment and thus explained the observed difference in regions with the use of renewable energy. Our results show a positive effect of spatial effects and geographic factors, which confirms research [110] on the impact of regional policies and infrastructure on neighborhoods. This is particularly relevant for solar and wind energy, where natural conditions determine the feasibility of different renewable sources. For example, as geography favors certain energy types, solar energy is predominantly harnessed in the south and wind energy in the north [110]. Olivier & Del Lo [110] argue that there is a need for regional cooperation and policy harmonization to enhance renewable energy use. Income positively impacts the growth of bioenergy and solar energy, but has a less consistent impact on wind energy due to regulatory and land-use constraints.

3.7. Technological Determinants

The implementation and effectiveness of renewable energy solutions are influenced by technological developments. Improvements in energy generation, storage, and grid integration due to eco-innovation, technological developments, and technical advances are making renewable energy more affordable and accessible. These developments increase the competitiveness of clean energy solutions by reducing environmental damage and increasing energy efficiency, thus contributing to the sustainability goals. This section focuses on the impact of changes driven by eco-innovation, technological progress, and innovations, and explores the main technological factors influencing the adoption of renewable energy (Figure 9). By understanding how these elements contribute to energy transition, we will be able to assess the important role of technology in accelerating the change towards a more sustainable energy future.

Eco-Innovation, Technological Innovations, and Technological Progress

Our findings demonstrate two positive outcomes related to eco-innovation, thereby providing support to the works of Li et al. [39] and Wang et al. [111], which were able to recognize eco-innovation as an important variable in the consideration for the adoption of renewable energy. These authors convey that eco-innovation is capable not only of increasing the utilization of clean energy technologies but also of assisting in lowering environmental damages with the help of diverse policies, thereby enabling nations to achieve specific climate goals. Figure 9 demonstrates, as well, five positive influences concerning the progress and innovations of technology, and is in accordance with the conclusions of Awijen et al. [58], which proposed the innovation of renewable energies as a new variable of explanation. Their work illustrates the central importance of innovations in technology in the accomplishment of Sustainable Development Goal Number 7 (Affordable and Clean Energy), a standpoint which our findings robustly endorse. The importance of innovation in technology in the integrated use of renewable energy resources is further stated in the works of Khan et al. [112], which reported the causality between these phenomena in Germany. It was found that technological advancements facilitate the uptake of renewable energy through enhanced energy storage and infrastructure. On the other hand, increased deployment of renewable energy accelerates further innovation by stimulating focused research, system integration, and improving efficiency at a higher order. Similarly, Sampene et al. [50] argue that technological innovation has an impact on the transition to renewable energy in E7 countries. This underlines the importance of these aspects for a sustainable energy transition. This finding is further supported by Alam and Murad [36] and Sun et al. [95], who found that technological advances play an important role in increasing the uptake of renewable energy.

3.8. Social Determinants

Social determinants also have a strong influence on the uptake and deployment of renewable energy technologies. Public attitudes, awareness, financial situation, and demographic characteristics determine consumer behavior and willingness to switch to clean energy solutions. While environmental concerns and perceived benefits drive deployment, factors such as cost, trust, and risk perception can help or hinder renewable energy deployment. This section is divided into four key areas: (1) Attitudes Towards Renewable Energy (Behavioral Beliefs)—Intention to Use, (2) Subjective Norms Towards Renewable Energy (Normative Beliefs and Institutional Trust)—Intention to Use, (3) Perceived Behavioral Control and Public Participation in Intention to Use, and (4) Other Social and Demographic Factors.

3.8.1. Attitudes Towards Renewable Energy (Behavioral Beliefs)—Intention to Use

Public attitudes towards renewable energy are influenced by a range of behavioral beliefs, including environmental concerns, value orientations, and perceptions of benefits and costs. These beliefs influence individuals’ willingness to adopt renewable energy technologies and their overall support for the clean energy transition. Factors such as awareness, trust, financial incentives, and ease of use further determine the level of engagement with renewable energy solutions. This sub-section examines the main behavioral beliefs that encourage or discourage the adoption of renewable energy, focusing on environmental concern and value orientation, awareness of renewable energy, preference for renewable energy types, perceived benefits and costs, financial incentives, ease of use, trust and perception of risk, ownership, visibility, and the impact of employment opportunities (Figure 10).

Environmental Concern, Environmentally Responsible Behaviors, and Value Orientation

Different behavioral beliefs, such as concern for the environment, value orientation, and responsibility, significantly influence the usage of renewable energy sources. Our study of the data shows that public opinions on renewable energy are mostly shaped by environmental concern. Particularly, we found seven positive impacts directly attributable to concern for the environment [113,114,115,116,117,118,119]. However, Irfan et al. [120] reported in another study that there was no significant correlation between concern for the environment and consumers’ willingness to use renewable energy in Pakistan. In addition to environmental concerns, value orientation is another belief related to the use of renewable energy. Asif et al. [121] proved that orientation to values is an important characteristic that determines attitudes and even the motives for using renewable energy. Furthermore, Wall et al. [113] and Lin et al. [122] showed the considerable effect of energy-saving habits on the use of renewable energy technologies. Kosenius and Ollikainen [123] explored further the environmental and societal trade-offs of renewable energy sources in Finland, remarking that public preferences are particularly influenced by concerns about biodiversity loss.

Awareness of Renewable Energy (RE)

Our findings suggest that consumer awareness is vital for the acceptance of renewable energy technologies. We found five positive correlations between consumer awareness of renewable energy and their willingness to utilize it [113,116,118,120,124]. On the other hand, Kontogianni et al. [125] brought attention to the low level of knowledge about the available energy sources in the regional electricity market. This gap constitutes a major shortfall as far as the availability of credible and dependable information is concerned. Such unawareness may obstruct the region’s endeavors to promote renewable energy and sustainability initiative adoption. Additionally, Lin et al. [122] also verified that the level of environmental awareness has a direct impact on adopting sustainable energy options.

Preferences for Renewable Energy Types

The research suggests that distinct individual preferences exist even within renewable energy resources. For instance, Kontogianni et al. [125] observe that certain populations in different regions prefer specific renewable energy sources (RESs) due to the successful local projects that have been implemented. As an illustration, people living in the Eressos region tend to favor the onshore wind energies because of the successful wind farm projects in the area, whereas people in Polychnitos tend to favor geothermal energies due to the high geothermal fields in the region. Similarly, Oluoch et al. [114] observed that the public has preferences for certain types of renewable energy, a finding also supported by Kosenius and Ollikainen [123], who reported that people prefer specific RES technologies.

Renewable Energy Benefits

Our research results suggest that the adoption of renewable energy technologies is significantly shaped by the perceived benefits of engaging with these technologies. In particular, five positive impacts indicate that the perception of the advantages of renewable energy has a great deal to do with the adoption of renewable energy technology. This support is found in multiple studies 113,116–118,126]. Contradicting evidence exists, however. For instance, Irfan et al. [120] claimed that the benefits that accrue from the usage of renewable energy (RE) have no bearing on the probability of its adoption. Asif et al. [121] suggest that utilitarian benefits significantly and positively affect attitudes toward renewable energy. Moreover, Khalid et al. [115] found that the relative superiority of renewable energy technology is an important determinant of its adoption, a finding that Nazir and Tian [124] also confirmed, noting its significant impact on consumers’ attitudes towards renewable energy technology.

Cost of Renewable Energy

Our studies revealed two separate views regarding the impact of costs on renewable energy adoption. Some claim that the expenditure significantly impacts attitude and adoption. In the same finding, Park and Ohm [126] pointed to perceived costs as a notable pointer in attitude formation of the public in regard to the use of renewable energy technologies. Analogously, Lin et al. [122] positively linked low costs with increased deployment rate. Irfan et al. [116] argued to the contrary that high costs imply a low willingness to use renewable energy, a finding that was further supported by another study by Irfan et al. [120], which found that high costs lead to a negative consumer intention to use renewable energy. Other studies, however, claim that costs do not determine deployment at all. Wall et al. [113], for instance, reported that the costs of renewable energy did not have a significant impact on deployment. Similarly, Khalid et al. [115] concluded that initial costs did not significantly influence adoption decisions.

Financial Incentives

The analysis suggests that financial incentives are crucial in encouraging the use of renewable energy. Khalid et al. [115] observe that the greater the financial incentive, the greater the deployment of renewable energy technologies. Similarly, Sardianou and Genoudi [127] pointed out the importance of tax incentives and subsidies to facilitate the shift towards renewable energy sources.

Ease of Use of Renewable Energy

We found two notable outcomes regarding ease of use. Khalid et al. [115] pointed out that ease of use affects adoption rates, such as ease of use’s influence on renewable energy (RE) adoption as discussed by Nazir and Tian [124]. Taken together, these studies highlight the importance of user friendliness in the adoption and deployment of new technologies.

Risk and Trust Perception of Renewable Energy

Trust and risk perceptions of renewable energy play an important role in deployment, which we have revealed. We identified two significant findings in this regard. Park and Ohm [126] tracked shifts in South Korean sentiment for renewables after the Fukushima disaster and found that trust in these technologies increased post-accident. They support the idea that perceived risk and trust are important factors in determining public acceptance. Wall et al. [113] also reported these perceptions being positively correlated to the adoption of renewable energy technologies. Khalid et al. [115], however, reported that those factors do not have an impact on adoption.

Ownership, Visibility, and Employment

Our analysis indicates that employment has a positive impact, whereas ownership, distance, and visibility are not considered primary concerns. This supports the findings by Oluoch et al. [114]. Oluoch et al. [114] set out to assess public attitudes towards a range of renewable energy technologies and found that although ownership, distance, and visibility did not play a significant role, the job creation potential from renewable energy infrastructure was highly appreciated.

3.8.2. Subjective Norms Towards Renewable Energy (Normative Beliefs and Institutional Trust)—Intention to Use

Social norms and institutional trust play a crucial role in shaping public attitudes towards renewable energy. Individuals are influenced by the behavior of those around them, including neighbors and wider societal trends. In addition, trust in public authorities, regulators, and environmental organizations influences the perceived credibility and effectiveness of renewable energy policies. This sub-section explores the role of collectivism and institutional trust in the adoption of renewable energy. It examines how perceptions of neighbor participation, collectivism, and trust in public institutions affect individuals’ willingness to engage in renewable energy decisions (Figure 11). Understanding these factors can help policy makers and stakeholders to develop strategies that build public trust and promote global participation in the clean energy transition.

Our research indicates that perceptions of neighbor participation can have a significant impact on consumer intentions to adopt renewable energy. Irfan et al. [120] found that an individual’s motivation to participate in renewable energy solutions is increased by the involvement of their neighbors. Contradictory data from another study by Irfan et al. [116] indicate that participation by neighbors may not significantly contribute to acceptance of renewable energy. Beyond that, our results suggest that collectivism is very important in attitudes towards renewable energy. According to the statement by Asif et al. [121], positive correlations with favorable attitudes toward RE were stronger in collectivist societies. This supports the argument that combined societal objectives can increase support for sustainability efforts. In addition, our analysis also indicates that confidence in governmental agencies and the public sector profoundly influences social attitudes towards the adoption of renewable energy. Kontogianni et al. [125] underscore that while environmental NGOs and regulatory bodies seem to be trusted, there is a huge lack of faith in the central governments. This seems to be a barrier to effective renewable energy policies, as trust in government is crucial to the successful implementation of these policies.

3.8.3. Perceived Behavioral Control and Public Participation—Intention to Use

Perceived Behavioral Control and Public Participation are also important factors influencing an individual’s willingness and ability to adopt renewable energy technologies. Perceived self-efficacy, or a person’s belief in their ability to use renewable energy solutions, plays an essential role in shaping consumer behavior. When individuals have confidence in their ability to integrate renewable energy into their daily lives, they are more likely to adopt such technologies. Public Participation in energy policy decisions is also key to fostering community support and acceptance of renewable energy projects. Insufficient community participation can lead to resistance, which reduces the effectiveness of energy transitions. This sub-section explores the impact of perceived self-efficacy and Public Participation on renewable energy deployment (Figure 12).

Perceived Self-Efficacy

We established that self-efficacy, defined as one’s belief in their capacity to acquire and utilize renewable energy (RE) technologies, affects both acceptance and behavioral intentions to a large degree. Our analysis finds four main results related to the role of self-perception of efficacy concerning public acceptance and intended behavior toward renewable energy adoption. As noted by Irfan et al. [116], self-perceptions of effectiveness positively influence an individual’s acceptance of renewable energy (RE) resources. This means that individuals who feel they can assimilate RE solutions into their daily routines are more inclined to endorse and adopt them. In a related study, Irfan et al. [120] suggest self-efficacy as a vital factor predicting consumers’ intentions to adopt renewable energy, thereby supporting the contention that an individual’s belief in their ability to shift towards renewable energy serves as a major motivational factor. Supporting these findings, Fazal et al. [117] illustrate that self-efficacy beliefs affect household intentions toward RE consumption. Their study shows that individuals who perceive themselves as knowledgeable and capable of managing renewable energy systems are more likely to incorporate such solutions in their energy consumption choices. Similarly, Wall et al. [113] found a positive relationship between perceived self-efficacy and willingness to use renewable energy technologies (Figure 12).

Public Participation

In energy policy, aside from individual perception, the impact of community involvement is yet another very important consideration. As Kontogianni et al. [125] point out, many people are frustrated by issues related to their lack of participation in decision-making related to renewable energy projects. Similarly, Lennon et al. [128] reveal that such exclusion often has unintended social and economic consequences, often displacing local communities. Together, these studies point to a much deeper problem: a problem where citizens are often relegated to passive consumer roles with minimal influence over energy policies. This lack of participation can undermine the development and acceptance of renewable energy projects, as community support is crucial for the implementation of these projects.

3.8.4. Other Social and Demographic Factors

Factors such as subjective well-being, public health, education, income levels, urbanization, and population growth influence individual and societal preferences for renewable energy technologies. In addition, demographic differences such as age, gender, and income influence attitudes towards clean energy solutions and willingness to move away from fossil fuels. This subsection examines the influence of subjective well-being, life expectancy, public health, education, and various demographic factors on renewable energy deployment (Figure 13).

Subjective Well-Being

Subjective well-being is found to positively correlate with renewable energy consumption. Kumari et al. [129] studied the G20 members and concluded that, with the use of renewables, the quality of the environment (e.g., reduction of CO₂ emissions) and subjective well-being using the Cantril life ladder index can be achieved. Conversely, the use of non-renewables is associated with a decrease in well-being. The results reaffirm that the promotion of renewable energy can promote both environmental sustainability and shared prosperity, thus reinforcing its role in sustainable development.

Life Expectancy

We discovered another interesting result related to the deployment of renewable energy technologies. We observed three positive correlations relating life expectancy to the consumption of renewable energy sources. A study by Vatamanu et al. [130] found that renewable energy consumption significantly increases life expectancy in 27 European countries between 2000 and 2020: a 1% increase in renewable energy consumption increases life expectancy by a factor of 0.331. Also, the impact of renewables on life expectancy is largely dependent on their potential to lower air pollution levels. Rodriguez-Alvarez [131] examined 29 European countries and found that air pollutants such as NOx, PM10, and PM2.5 significantly decrease life expectancy at birth, with fine particulate matter (PM2.5) posing severe health risks. The study shows that, indeed, pollution is one of the main reasons for the low life expectancy, and therefore, greater investment in renewable energy is required to decrease the number of deaths associated with pollution and, in turn, raise the quality and length of life. Similarly, Wang et al. [132] found a positive correlation between renewable energy consumption and life expectancy, highlighting the double threshold effect of GDP per capita. The benefits of renewables on life expectancy are more pronounced after certain levels of economic advancement, especially in developed countries. The study adds to the argument that health and energy policies should be integrated to reap the maximum benefits.

Public Health and Health Expenditures

Our results suggest that the use of renewable energy improves public health and lowers health expenditures. This has been shown by a number of studies across different regions. Li et al. [49] stated that fully switching to renewable electricity in Los Angeles by 2045 would result in considerable decreases in harmful pollutants’ emissions, major improvements in public health from lowered mortality rates, and economic gains. Koengkan et al. [92] noted that in the Latin America and the Caribbean region, higher consumption of RE translates to lower mortality rates due to air pollution. Additionally, the study also highlights the indirect health benefits, as increased use of renewable energy reduces the consumption of fossil fuels, which further improves air quality and public health. Apergis et al. [133] stated that in 42 Sub-Saharan African countries, the consumption of renewable energy (RE) leads to a decrease in CO₂ emissions, thus alleviating expenditures on health in the long run. Researchers point out the dual advantages for environmental sustainability as well as public health [133]. Ullah et al. [134] pointed out that in Pakistan’s health expenditures are negatively impacted by trade-induced CO₂ emissions, while RE helps in controlling both emissions and health expenditures. This improves the quality of the environment and lessens the burden of healthcare. Alharthi et al. [135] discussed the improvement in public health outcomes resulting from the shift from fossil fuels to RE in the MENA region.

Education

It has come to our attention that there is a correlation between renewable energy consumption and higher levels of education. Sart et al. [42] stated that in emerging market economies, both educational attainment and economic growth have a renewable energy adoption favorable impact. The analysis of causality proves that improved education is associated with increased use of RE. Education enhances the adoption of RE in South Asian countries [136].

Demographic Factors

The analysis shows that those with higher education and income are more likely to use renewable energy technologies [118,123,125,127]. Furthermore, different age groups seem to respond differently in attitudinal terms. Middle-aged and younger people are more likely to choose renewable energy technologies, but the willingness to pay for green energy decreases with age [123,127]. Some studies show that men prefer renewable energy (RE) [123]. However, other studies have not found a significant impact of gender or marital status on the decision to adopt renewable energy technologies, suggesting that these demographic factors may not be universally predictive [127]. Renewable energy adoption is also influenced by urban development and population growth. Mohamed Yusoff et al. [46] showed that urbanization has a positive impact on the use of renewable energy. Meanwhile, Kang et al. [40] indicated that there is a significant relationship between urban population growth and the use of renewable energy. Likewise, Akintande et al. [76] verified that renewable energy usage in particular regions of the world is based on urbanization and population expansion. However, Sampene [50] takes the opposite view, finding that urbanization hinders the transition to renewable energy sources (RESs), arguing that rapid urban expansion can increase energy demand and slow down the transition to renewables.

3.9. VOSviewer

The study applies a bibliometric analysis using VOSviewer, revealing interrelated themes covering economic, environmental, energy, political, regulatory, regional, technological, and social factors. Keyword co-occurrence analysis and citation network analysis further map the academic landscape of renewable energy research by highlighting influential studies and research clusters (Figure 14). With min-occurrence = 2, the map retains 188 of 577 keywords and resolves into five clusters. These clusters align with the systematic literature review themes, as detailed in the paragraph below describing the color meanings. The map supplements, rather than changes, the systematic literature review by quantifying term prominence (occurrences and total link strength (TLS)) and highlights cross-cluster bridges (e.g., energy poverty, institutional quality, and green finance), thereby clarifying linkages across determinant groups. The red cluster, associated with public acceptance and behavior, illustrates the significance of social determinants, including societal attitudes, community acceptance, and financial readiness, which can support or hinder the realization of renewable energy projects. The green cluster, associated with sustainability and policy, highlights the impact of policy and regulatory frameworks, such as energy governance, equity, and energy poverty, thereby underlining the necessity for stable policies and equal access. The blue cluster, representing emissions and economic growth, emphasizes environmental and economic dimensions, prioritizing the relationship between carbon emissions, pollution, and economic growth—essential drivers in the shift towards renewable energy resources. The yellow cluster, associated with trade and financial development, mentions economic and financial dimensions, echoing the importance of trade, foreign direct investment (FDI), and energy prices in driving investments in renewable energy. Finally, the purple cluster, which addresses health and human development, emphasizes the socioeconomic factors, illustrating the broad influence of access to energy on health and overall well-being. These clusters intersect since they recognize the interdisciplinary nature of research in renewable energy, where technological innovation (such as efficiency improvement and integration into the grid) and geographic variation in resource availability and infrastructure also have significant parts to play. The network, therefore, offers a visual integration of the many economic, environmental, energy, technological, policy, regulatory, regional, and social factors that cumulatively influence the implementation of renewable energy technologies.

4. Discussion and Conclusions

This study provides a systematic and comprehensive analysis of the key determinants influencing the deployment of renewable energy technologies. Relative to earlier syntheses, this study (i) covers the period 2013–2025, (ii) integrates bibliometric mapping (VOSviewer) with a SALSA/PRISMA workflow, (iii) systematizes eight determinant groups into an extensive set of sub-determinants, and (iv) foregrounds social and regional determinants alongside established economic and policy drivers. This analysis contributes to the discussion on the determinants that are important for understanding the different trends in renewable energy deployment in different countries.

The citation topic analysis highlights an important trend in the literature: renewable energy deployment is mainly addressed in economic–environmental discourse, rather than as a distinct research focus. Despite the targeted search strategy, 74.5% of the selected publications were assigned to the Environmental Kuznets Curve (EKC), and only 14.5% of the publications were explicitly attributed to the topic of renewable energy. In addition, almost half (48.2%) of the publications were related to energy fuels, while 44.5% were related to the ecology of environmental sciences. While this distribution shows that the literature is multidisciplinary and suggests that renewable energy is an important issue in these fields, an analysis of citation themes reveals that research specifically addressing the determinants and processes underlying renewable energy deployment remains a relatively limited part of the literature.

Using the SALSA approach and bibliometric analysis with VOSviewer, we systematically identify and categorize the main economic, environmental, energy, political, regulatory, regional, technological, and social determinants of renewable energy deployment. In addition, we highlight the contradictory results, ensuring that our findings reflect the complexity and nuances of the actual deployment of renewable energy.

Our analysis reveals that economic determinants play a crucial role in shaping renewable energy deployment. Across income groups, economic growth generally supports renewable energy (RE) deployment, with the strongest effects in high- and middle-income countries; in low-income settings, weak financial and technological capacity dampen this link [51]. Energy price effects are context-dependent: higher fossil prices can stimulate RE, yet fossil-dependent economies may double down on incumbents [28,51,53,54]. Financial development and green finance (e.g., green bonds and carbon markets) consistently enable deployment by lowering capital costs and risk. The effects of FDI, trade openness, economic complexity, and globalization are mixed and contingent on economic structure. Shadow economy activity undermines enforcement and investment. At scale, RE deployment contributes to jobs and human capital and can be designed to narrow socio-economic disparities.

The findings underline that environmental determinants have a significant impact on the deployment of renewable energy. Evidence converges on a positive association between higher RE use and lower CO₂ emissions, with co-benefits for air quality and environmental degradation; effects are largest where technology readiness and stable support instruments are in place [27,28,32,40,53,82,86,87,88,89,90,91,92,93,94,95].

Energy determinants highlight the interplay between energy security, energy poverty, and renewable energy deployment. Energy security concerns, especially under geopolitical risk, push systems toward domestic RE alternatives, while incumbent fossil fuel lobbies remain a major barrier [44,54,55,88]. Energy poverty can motivate decentralized RE solutions where access to modern energy is limited [96,97,98,99]. The fossil–RE relationship captures the core transition tension: security needs versus decarbonization goals.

Political determinants reveal that political stability, institutional quality, and governance effectiveness are important factors in promoting renewable energy [31,52,58,59,71,100]. Strong political institutions and democratic governance structures create a favorable environment for renewable energy policies, while political risks and policy inefficiencies discourage investment.

Regulatory determinants such as the Kyoto Protocol and the stringency of environmental policy have a significant positive impact. Incentive mechanisms such as feed-in tariffs and net metering stimulate the growth of renewable energy [54,55,95,103,104]. However, the effectiveness of energy pricing and carbon pricing is different and requires context-specific regulatory approaches. The negative impact of Natural Resource Rents shows that resource-rich countries may not invest enough in renewable energy sources, which calls for policies to channel resource revenues towards sustainable energy development.

Regional determinants underscore the dual role of geopolitical risks. Geopolitical risks have both a positive and a negative impact on the deployment of renewable energy. While energy security concerns encourage investment in renewable energy in high-income countries, geopolitical instability hampers its deployment in middle-income regions [54,95,106,107]. Natural resources and geographical factors also shape the deployment of renewable energy, as resource-rich countries in some cases generate revenues for investment in renewable energy, while others remain dependent on fossil fuels. Spatial spillovers demonstrate the role of regional policy coordination in optimizing the use of renewable energy [108,109,110].

Technological determinants, particularly technological progress and eco-innovation, contribute significantly to the use of renewable energy by increasing efficiency and reducing costs [36,39,50,58,95,111,112]. The bidirectional relationship between technological advancements and renewable energy deployment underlines the importance of continuous investment in research and development. Countries with strong innovation ecosystems are better placed to accelerate the transition to renewable energy, which requires targeted policy support to foster technological innovation.

Our analysis reveals the significant role of social determinants in shaping the deployment of renewable energy technologies. Environmental concern, pro-sustainability values, routine energy-saving habits, and focused awareness all support RE acceptance and adoption, though effect sizes vary by culture and context. Preferences are shaped by local experience with specific technologies. Financial incentives mitigate upfront-cost salience. Ease of use, risk perception, and trust (in government and suppliers) condition acceptance; participatory processes and community benefits (jobs and ownership) raise support. Perceived self-efficacy predicts adoption intention. Education, income, and (often) urbanization increase uptake, albeit with context-specific exceptions [40,42,46,118,123,125,127,136]. Beyond energy outcomes, higher RE use is associated with better well-being, longer life expectancy, and improved public health via pollution reductions [49,92,93,94,95].

A comprehensive conceptual and empirical literature analysis has identified a set of determinants influencing renewable energy deployment. Based on this set of determinants, it is possible to empirically analyze the determinants of renewable energy deployment and apply them to a specific region or another context. Overall, these identified conceptual and comprehensive factors influencing the implementation of renewable energy can be further developed conceptually to create a fully comprehensive set of determinants. This study extends previous research by going beyond country-specific sampling and single renewable energy sources, updating the evidence base for 2013–2025, and incorporating socio-demographic dimensions (e.g., population characteristics and attitudes toward renewable energy technologies). Earlier studies emphasized macroeconomic drivers (income and fossil fuel prices) and CO₂ outcomes; our broader 2013–2025 window confirms these signals but shows greater heterogeneity by income group and policy design [9,10,11]. Europe-focused syntheses that elevated policy over market forces are largely corroborated, while our global scope shows policy effectiveness is instrument and capacity dependent (e.g., FIT/net-metering > broad carbon pricing in low-capacity settings) [12,13]. Compared to pre-2010 mappings, we surface newer levers, green finance, energy poverty, and geopolitical risk, and add a clearer social/behavioral layer [14]. Finally, we expand country-level determinant catalogs through bibliometric clustering and an integrated eight-pillar framework that links determinants to actionable policy levers [15]. The insights from this analysis not only contribute to academic research but also provide valuable policy implications for governments, investors, and industry stakeholders. Despite its comprehensive analysis, the study has several limitations.

Regional differences in the economic and political situation limit the generalizability of the results and therefore affect the application of some factors in other countries. In addition, the study does not fully explore the relationship between several factors, such as the interaction between political stability and technological progress in the deployment of renewables. Furthermore, measuring subjective factors like public attitudes, institutional quality, and geopolitical risks remains difficult due to a lack of consistency in data collection and interpretation. Finally, because our initial search relied on Web of Science as the primary database, a residual risk of omission remains; although we mitigated this via backward/forward citation chasing and manual journal checks, some studies indexed elsewhere may not have been captured.

To address these limitations, several future research directions are recommended. Comparative analysis between developed and developing countries offers more tailored policy recommendations and provides a better understanding of how local economic, political, and environmental factors influence renewable energy deployment through regional and country-specific studies. Additionally, a causal analysis should be carried out to assess the impact and effectiveness of specific renewable energy policies to ensure a clearer understanding of their impact on deployment outcomes. Furthermore, future research should examine the role of social acceptance and behavioral economics in renewable energy deployment, exploring how psychological, cultural, and economic factors shape public attitudes to help policy makers design more effective interventions. Moreover, geopolitical risks and international energy trade policies should be further explored to understand how global energy crises, trade disputes, and political conflicts impact renewable energy investments. Finally, future research should focus on ensuring a just transition by assessing the socio-economic impacts of renewable energy deployment on marginalized communities, job creation, and income distribution.

In conclusion, the deployment of renewable energy is driven by a complex interplay of economic, environmental, energy, political, regulatory, regional, technological, and social elements. While changes in political systems, financial systems, and technological innovations are accelerating the acceptance of renewable energy, even in these areas, the challenges of fossil fuel dependency, regulatory uncertainty, and regional disparities remain to be addressed. Ensuring a successful and sustainable global transition to renewable energy will depend on a holistic and integrated approach that includes strong governance, financial incentives, technological innovation, and Public Participation.