Non-Technical Barriers and Transition Pathways for Vehicle-to-Grid: A Systematic Review of 974 Studies and a Socio-Technical Framework

Abstract

Vehicle-to-grid (V2G) can provide flexibility and storage for low-carbon power systems while supporting sustainable mobility, yet real-world deployment remains largely confined to pilots despite substantial technical progress. This article presents a PRISMA-guided systematic review of 974 V2G/V2X studies published between 2009 and 2025 to explain why implementation lags and how it can be accelerated. Within this corpus, a total of 162 implementation-critical articles are identified and, within these, 95 studies that primarily address non-technical dimensions such as policy, markets, user behavior, and ecosystem coordination. Drawing on full-text coding, a four-domain socio-technical framework is developed that clusters recurring non-technical barriers and enablers into business–economic, governance–policy, social, and infrastructure and ecosystem domains. The analysis reveals (i) a temporal shift from technical dominance to multidisciplinary acceleration after 2021; (ii) distinct regional priorities in which Europe emphasizes regulation and business models, Asia focuses on infrastructure scaling, and the Americas on frequency services and resilience; and (iii) persistent revenue uncertainty, regulatory gaps, user resistance, and grid unreadiness as cross-cutting obstacles. For each domain, concrete transition levers and indicative deployment key performance indicators (KPIs) are derived, such as multi-actor revenue-sharing mechanisms, aggregator recognition in market rules, privacy-by-design user participation models, and targeted bidirectional charging deployment in constrained grids. Synthesizing these insights, three archetypal V2G transition pathways are proposed—regulation-led, infrastructure-first, and service-driven—that reflect regional conditions and offer alternative routes to large-scale adoption. The framework and roadmap provide researchers, policymakers, system operators, and mobility providers with an integrated basis for designing, monitoring, and evaluating V2G policies, business models, and pilots in line with energy system decarbonization goals.

1. Introduction

Vehicle-to-grid (V2G) technology can accelerate the energy transition by enabling electric vehicles (EVs) to decarbonize transport while providing flexibility and storage to electricity networks with rising shares of renewable generation [1,2]. Yet despite considerable technical progress in bidirectional charging and battery management, the translation from demonstration projects to large-scale deployment remains constrained by business feasibility, regulatory readiness, consumer behavior, and ecosystem integration [3,4].

A total of 974 V2G/V2X studies were published between 2009 and 2025, indicating that technical solutions abound, but deployment still lags due to overlooked non-technical barriers. Europe has commercialized V2G mainly through pilots, several Asian countries focus on infrastructure scaling, and global standards are maturing—revealing implementation gaps that this paper addresses. By systematically identifying and categorizing these gaps, this review contributes to SDG 7 (Affordable and Clean Energy) and SDG 13 (Climate Action). Existing reviews have catalogued barriers and enablers across technical, economic, policy, and social dimensions, but they rarely translate these insights into explicit transition pathways or measurable indicators that can guide implementation. Most studies remain rooted in single disciplines or sectors, resulting in siloed understandings of V2G that are difficult to apply in real projects. There is therefore a need for an integrated, empirically grounded framework that diagnoses these silos and specifies how combinations of policies, business models, infrastructures, and user practices can move V2G from niche pilots to mainstream system integration.

This systematic review analyzes 974 publications (2009–2025) to derive a four-domain framework—Business/Economic, Governance/Policy, Social, and Infrastructure and Ecosystem—that explains why V2G scaling remains fragmented despite technical maturity. Within this corpus, 164 high-relevance papers reveal distinct regional priorities: Europe emphasizes regulatory design and business models, Asia infrastructure scaling, and the Americas frequency services and resilience. Temporal trends show multidisciplinary acceleration after 2021, confirming non-technical factors as the primary deployment bottleneck.

Building on this baseline, the analysis translates empirically derived barriers into actionable requirements for regulators, energy companies, and researchers, including revenue-sharing mechanisms, regulatory harmonization, user trust architectures, and interoperable infrastructure. By identifying 95 non-technical papers as a dedicated technology-transfer knowledge base, the framework provides a roadmap for V2G commercialization across global contexts and helps to prioritize policy and investment decisions. At the same time, it offers a basis for designing and later validating interventions in concrete pilots, including urban demonstrators such as the MOBILITIES for EU project [5].

The paper proceeds as follows. Section 2 details the Web of Science search strategy and PRISMA-guided screening protocol. Section 3 presents regional, temporal, and keyword-based analyses of the 974-article corpus. Section 4 formalizes the four-domain framework. Section 5 derives domain-specific transition levers, Section 6 outlines archetypal V2G pathways and indicative KPIs, Section 7 discusses implications and future research, and Section 8 concludes.

Against this backdrop, Energies has hosted a growing body of work on the integration of EVs into power systems, including reviews on EV charging, smart grids, and V2G services [6,7]. Building on and extending this literature, this article makes three main contributions. First, it provides an empirically grounded framework for V2G implementation derived from 974 V2G/V2X publications (2009–2025), with a specific focus on non-technical barriers, transition levers, and deployment indicators. Second, it systematically maps business–economic, governance–policy, social, and infrastructure and ecosystem domains across regions and over time, complementing predominantly technical reviews with an integrated implementation perspective. Third, it offers a roadmap that links V2G research to concrete regulatory, market design, and infrastructure planning decisions for regulators, system operators, aggregators, and mobility providers, which aligns with the applied energy systems focus of the readership of Energies. Several recent reviews provide valuable overviews of V2G technology, grid impacts, and implementation barriers across technical, economic, and policy dimensions [1,4,7]. However, these studies primarily catalogue challenges and opportunities at a high level and do not derive an empirically grounded, non-technical implementation framework, nor do they translate barriers into concrete transition levers with indicative KPIs or regionally differentiated pathways. In contrast, our review systematically maps 974 studies, isolates 162 implementation-critical and 95 non-technical or mixed articles, and uses this corpus to develop a four-domain socio-technical framework, domain-specific levers and KPIs, and three archetypal V2G transition pathways reflecting regional conditions.

In parallel to these non-technical debates, a growing body of work tackles secure and resource-aware V2G operation, for example bandwidth-conscious event-based secondary frequency control schemes and resilient joint monitoring of battery state-of-charge (SoC) and state-of-health (SoH) under cyber-attacks and communication constraints [4,8,9]. These studies are coded as predominantly technical in our corpus and therefore lie outside the main focus of this review, but they help delineate the boundary between control-oriented V2G research and the non-technical implementation challenges addressed here. Our contribution is thus complementary: the review concentrates on business, governance, social, and infrastructural conditions under which such secure and resource-efficient V2G solutions can be scaled in practice. Unlike prior reviews that list barriers without operational indicators, we extract and generalize explicit non-technical KPIs (e.g., share of markets with recognized aggregators, penetration of bidirectional chargers) that can be used for ex-post evaluation of pilots and policies.

2. Methodology

This PRISMA-guided systematic review [10] synthesizes 974 V2G publications from the Web of Science Core Collection (2009–2025), of which 162 implementation-critical articles were identified through structured screening (Figure 1). The review followed a pre-specified protocol comprising: (i) database and time-window definition, (ii) eligibility criteria, (iii) two-stage screening (title–abstract, then full text) with an abstract scoring threshold, (iv) full-text coding into technical/non-technical/mixed categories and four domains, and (v) a second-stage synthesis of non-technical and mixed papers into transition levers, KPIs, and pathways (Section 4, Section 5 and Section 6). The full search strings, scoring rubric, and screening flow are documented in Appendix A. This section summarizes the key elements and outlines the second-stage analysis that derives transition levers and indicative key performance indicators (KPIs). The 162 implementation-critical studies are listed in Appendix B with unique IDs and summary metadata, and all appear in the combined reference list generated from main.bib and included_studies.bib. The PRISMA 2020 Checklist is included in the Supplementary Materials.

Three foundational research questions guided the analysis: (RQ1) What are the barriers and enablers to V2G technology transfer across contexts? (RQ2) Does research disproportionately emphasize technical over governance, market, behavioral, or policy challenges? (RQ3) Which non-technical obstacles—such as policy gaps, business model uncertainty, user resistance, regulation, and stakeholder misalignment—remain most overlooked?

2.1. Search Strategy and Screening

The literature search was conducted in Web of Science for 2009–2025 to capture V2G’s evolution from niche pilots to grid-scale ambition. Only peer-reviewed journal articles written in English were included, while conference proceedings, reports, and theses were excluded. V2G concepts were combined with implementation- and barrier-related terms, for example:

“V2G” OR “bidirectional charging” AND “barrier” OR “policy” OR “market” OR “adoption” (see Appendix A for full queries).

In total, 1026 records were identified. After removing 52 duplicate records, 974 unique V2G/V2X articles remained and advanced to title–abstract screening.

Screening proceeded in two phases. In Phase 1, titles and abstracts were scanned for implementation signals (e.g., “pilot”, “demo”, “implementation”, “regulation”, “stakeholder”), reducing the set to 788 records. In Phase 2, a simple 0–3 abstract-relevance score was applied based on the density of barrier- and implementation-related terms (e.g., “barrier”, “challenge”, “policy”, “market”, “adoption”), and retained all studies with scores $\ge 3$, yielding 164 deployment-relevant papers for full-text eligibility review (Figure 1). This threshold (score $\ge 3$) was chosen to balance recall and precision: it excludes clearly peripheral mentions of V2G while preserving studies that engage with deployment, policy, markets, user behavior, or ecosystem integration in more than a cursory way. After full-text assessment, 162 were retained as implementation-critical V2G/V2X studies.

In summary, the PRISMA process yields 974 unique V2G/V2X papers after duplicate removal, of which 788 advance to title–abstract screening. Abstract scoring then identifies 164 deployment-relevant papers for full-text review, from which 162 are retained as implementation-critical V2G/V2X studies (Figure 1; Appendix A). Within these 162, 67 are classified as technical, 44 as non-technical, and 51 as mixed, and a subset of 95 studies (all 44 non-technical and 51 mixed where non-technical aspects dominate) form the deep-dive corpus for deriving transition levers and KPIs.

2.2. Boundary Setting

Included studies are peer-reviewed V2G/V2X articles that confront real-world friction—pilots, field trials, empirical case studies, or modeling grounded in specific regulatory, market, or infrastructural contexts. Excluded are non-peer-reviewed items (e.g., reports, theses), generic EV charging or storage studies without explicit V2G/V2X focus, and purely theoretical or simulation-only work that does not connect assumptions to deployment realities.

2.3. Socio-Technical Mapping

Full-text coding assigned each of the 162 implementation-critical papers to one of three categories: technical (67 articles), focusing primarily on engineering aspects and control; non-technical (44), analyzing policy, markets, user behavior, or institutional arrangements; and mixed (51), engaging both technical and non-technical dimensions substantively. Non-technical and mixed studies were further mapped into four recurrent domains—Business/Economic, Governance/Policy, Social, and Infrastructure and Ecosystem—forming the socio-technical framework used in subsequent analysis (

Table 1. Classification summary.

Category	Count
Technical	67
Non-Technical	44
Mixed	51

). During coding, decision rules were applied to assign multi-faceted issues such as interoperability, trust, data governance, or coordination to the domain that best reflected the primary lever involved (infrastructure standards, governance rules, social acceptance, or business models), and this convention was used consistently across all studies. For example, OCPP-related cyber-security concerns were coded under Infrastructure and Ecosystem when discussed as charger and network architecture issues, under Governance/Policy when linked to protocol mandates and market roles, and under Social when framed primarily in terms of user trust in data handling.

Classification into technical, non-technical, and mixed categories followed a simple but explicit rubric. Articles were labeled as technical when the problem framing, methods, and conclusions focused predominantly on engineering, control, optimization, or hardware/software reliability (e.g., charging and discharging protocols, grid stability, power electronics, communication architectures), with only incidental reference to policy, users, or institutions. They were labelled as non-technical when the primary emphasis lay on policy, markets, governance, business models, finance, stakeholder engagement, or social acceptance, and any technical modeling played a clearly supporting role. Studies were coded as mixed when they substantively engaged both sides, for example by combining detailed control or optimization models with explicit analysis of regulatory design, economic feasibility, or user behavior.

The first author conducted the initial coding of all 162 implementation-critical studies. A co-author independently reviewed all category and domain assignments, with particular attention to borderline and multi-domain cases. Disagreements were discussed until consensus was reached, and the codebook was iteratively refined to reduce overlap between categories and to clarify how multi-domain concepts were handled. The two authors verified that the final labels were applied consistently across the 162 implementation-critical studies. For transparency, Appendix B reports all 162 classified studies with their IDs, reference labels, years, and problem-type assignments (technical, non-technical, mixed), while the main reference list provides full bibliographic details; Appendix C offers coding examples for a subset of studies, including multi-domain issues.

Figure 1 summarizes the PRISMA flow from initial identification to final classification. These categories and domains provide the basis for the regional and temporal analyses in Section 3 and for the framework formalized in Section 4.

2.4. Second-Stage Analysis: Transition Levers and KPIs

From the 162 implementation-critical papers, 95 studies were identified that treat non-technical dimensions as their primary concern (all 44 non-technical papers and 51 mixed papers in which non-technical aspects dominate the problem framing or conclusions). These 95 papers form a dedicated knowledge base for technology-transfer analysis.

For each of the four domains, the coding captured (i) the dominant barrier and enabler types, (ii) the actors and institutional arrangements involved (e.g., regulators, DSOs/TSOs, aggregators, mobility providers, users), and (iii) any quantitative or qualitative indicators used to judge V2G implementation progress (e.g., penetration of bidirectional chargers, existence of an aggregator role, user retention in pilots, or presence of V2G clauses in grid codes). These indicators were then grouped by domain and by emerging transition levers, and generalized into a small set of 2–4 indicative KPIs per lever. Only metrics that (i) can be observed or measured in real systems, (ii) are comparable across jurisdictions and project types, and (iii) appear with sufficient frequency or emphasis in the reviewed studies to suggest wider relevance were retained. The resulting KPIs are thus not arbitrary proposals, but abstractions of measurement practices already present in the implementation-focused V2G literature.

For each of the four domains, the coding captured: (i) the dominant barrier and enabler types; (ii) the actors and institutional arrangements involved (e.g., regulators, DSOs/TSOs, aggregators, mobility providers, users); and (iii) any explicitly stated or implicit quantitative and qualitative indicators used to assess deployment progress (e.g., penetration of bidirectional chargers, existence of aggregator roles, user acceptance metrics, tariff or taxation schemes).

This coding was subsequently used to (1) derive domain-specific transition levers (e.g., revenue-sharing mechanisms, aggregator recognition, privacy-by-design architectures, infrastructure planning instruments); (2) propose indicative non-technical KPIs that can be used to monitor V2G progress across contexts, with illustrative formulas, units, and example use cases provided for a subset of KPIs in Table 6; and (3) synthesize three archetypal V2G transition pathways (regulation-led, infrastructure-first, and service-driven), each characterized by distinct combinations of domains, actors, and levers. These steps provide the basis for the transition pathways and roadmap presented in Section 4 and Section 6, and are designed to support both comparative analysis across regions and future ex-post evaluation of concrete pilots.

Full search strings, journal filters, the abstract scoring rubric, and examples of borderline decisions are provided in Appendix A for reproducibility.

3. Results Regional and Thematic Patterns

This systematic literature review covers 974 articles published between 2009 and 2025, demonstrating sustained global interest in V2G implementation. Drawing on the coding procedure described in Section 2, the results are organized by regional scope and thematic trends.

3.1. Scope, Regional Distribution, and Key Barriers

Together, these studies span engineering, economics, policy, and social science perspectives, but with marked imbalances across regions and time.

The studies span diverse geographic contexts with region-specific emphases:

Europe (Denmark, Finland, France, Germany, Greece, Italy, Netherlands, Norway, Poland, Spain, Sweden, Turkey, UK): Germany leads research on business model and regulatory hurdles. Notably, Sabadini and Madlener (2025) provide critical empirical evidence that challenges the common industry belief that “double taxation” kills the V2G business case, finding it largely untrue in the German context [11]. In the UK, early industry perspectives from Weiller and Neely (2014) were influential in predicting the slow roll-out of grid-scale V2G due to the lack of joint investment models [12]. Dutch research is characterized by its use of “living labs”; for instance, Huang et al. (2021) utilized real transaction data from Amsterdam to model EV driver willingness to participate in V2G contracts [13]. Nordic studies leverage high EV penetration to explore social factors, with Kester et al. identifying expert-driven policy mechanisms and public perceptions that shape adoption [14]. Additional contexts include regulatory reforms in Poland [15] and grid integration studies in Greece, Italy, Turkey, and Spain [16,17]. Further illustrative cases are summarized in Table 2, which highlights representative studies and their main contributions by region.

Asia/Middle East (Bangladesh, China, India, Iran, Japan, Jordan, Malaysia, Pakistan, Singapore, South Korea, UAE): China dominates research aligned with national carbon-neutrality goals. Zhang et al. (2024) present Shanghai as a global archetype for urban planning that integrates V2G into dense distribution networks and mobility hubs [18]. In India, Kumar et al. (2024) highlight the strategic choice between charging standards, noting that while CCS is popular, CHAdeMO currently offers superior support for practical V2G operation [1]. Japan leverages its long-standing CHAdeMO ecosystem to study the decarbonization potential of combining rooftop solar with EV batteries at scale [19,20]. Beyond these national cases, South Korean studies explore gamified participation mechanisms [21], work in the UAE and neighbouring countries investigates user perceptions via large-scale surveys [22,23], and a broader regional literature examines the pricing, market design, and techno-economics of V2G integration [24,25,26,27,28,29,30]. Further illustrative cases are summarized in Table 2.

Americas (Brazil, Canada, US): Research in this region focuses on grid impacts, frequency services, and resilience. In the US, Gehbauer et al. (2023) provide a critical economic case by demonstrating that active battery health management in military PEV fleets can increase ROI to 106.0%, helping to justify the high initial costs of bidirectional hardware [31]. Freeman and Agar (2025) are notable for analyzing the interplay between adoption and grid electrification in New England, positioning V2G as a primary tool for outage management and emergency resilience [32]. In Canada, Quddus et al. (2019) utilize real data from Ontario’s market to analyze the economics of frequency regulation [33]. Meanwhile, Brazilian studies such as Ruoso and Ribeiro (2022) identify cost and policy as the primary barriers in emerging markets through qualitative interviews with supply chain agents [34].

Australia: Framed as an “EV laggard” market, Australian research emphasizes consumer psychology and geographic hurdles. Philip et al. (2023) is particularly influential as one of the first studies to quantify the monetary value potential buyers place on V2G capability, finding a marginal willingness-to-pay between AUD 2319 and AUD 5346 [35]. Sommer and Hossain (2025) contribute to the infrastructure domain by using AI to optimize en-route charging selection, specifically tailored to Australia’s unique geography and high share of rooftop solar generation [36]. Additionally, Lucas-Healey et al. (2024) provide social insights into fleet trials, identifying how “organizational sensemaking” affects participation in V2G programs [37].

Africa (Egypt, South Africa): African studies address unique grid constraints, particularly in South Africa, where “load shedding” is a dominant concern. Ahjum and Lawrence (2023) provide a unique exploratory analysis of V2G for the minibus taxi industry, proposing this fleet as a short-term workaround for limited charging access due to their fixed, short-range routes [38]. Chapman and Madhoo (2025) examine the national utility Eskom, concluding that managed charging and V2G offer essential flexibility for mitigating supply shortages [39]. Further, Oni and Longe (2024) highlight the necessity of renewable-powered EV footprints to bypass local infrastructure limitations and high ownership costs [40].

Global Reviews and Others: A small set of worldwide syntheses benchmark V2G/V2X feasibility and barriers, including Mojumder et al. (2022), Biswas et al. (2025), and Eltohamy et al. (2025), which are particularly influential for our baseline mapping [41,42,43]. Additional case studies from Malaysia, Brazil, Greece, Italy, and the UAE cover islands, high-EV grids, and business models [44,45,46].

Taken together, these regional snapshots show how national contexts shape the framing of V2G as a business, regulatory, social, or infrastructural problem. To complement the narrative, Figure 2 and Table 2 summarize where V2G research has been conducted, typical case study locations, and characteristic non-technical barriers.

Table 2. Regional trends, case studies, and barriers in V2G research (2009–2025).

Region	Primary Research Focus	Notable Case Studies	Prevalent Barriers
Europe	Business models; taxation schemes; stakeholder engagement; pilot evaluations; smart charging tariffs	Berlin, Hamburg (Germany); London (UK); Amsterdam (Netherlands); Bornholm (Denmark)	Complex market regulation; double taxation; interoperability; pilot scalability; user trust [13,16]
Asia/Middle East	Infrastructure planning; V2G business ecosystems; market trading; CHAdeMO; PV + V2G	Shanghai, Beijing (China); Delhi (India); Tokyo (Japan); Seoul (South Korea)	Fragmented standards; uneven grid modernization; uncertain revenue; policy delays [47,48]
Americas	Frequency regulation; resilience; fleet electrification; techno-economic evaluations	Texas (ERCOT); California (US); Ontario (Canada)	Interconnection constraints; slow market reforms; inconsistent policies [49,50]
Australia	Consumer preference modeling; EV adoption lag; remote grid resilience	Sydney; Melbourne; regional corridors	Low EV penetration; long-distance travel; limited incentives [35]
Africa	Load-shedding resilience; taxi fleet electrification	Cape Town; Johannesburg (South Africa)	Affordability; limited infrastructure; grid instability [51]
Global reviews	Cross-regional benchmarking; techno-economic barriers	Global scope	Lack of unified protocols; insufficient pilots; revenue uncertainty [41]

Table 2. Regional trends, case studies, and barriers in V2G research (2009–2025).

Region	Primary Research Focus	Notable Case Studies	Prevalent Barriers
Europe	Business models; taxation schemes; stakeholder engagement; pilot evaluations; smart charging tariffs	Berlin, Hamburg (Germany); London (UK); Amsterdam (Netherlands); Bornholm (Denmark)	Complex market regulation; double taxation; interoperability; pilot scalability; user trust [13,16]
Asia/Middle East	Infrastructure planning; V2G business ecosystems; market trading; CHAdeMO; PV + V2G	Shanghai, Beijing (China); Delhi (India); Tokyo (Japan); Seoul (South Korea)	Fragmented standards; uneven grid modernization; uncertain revenue; policy delays [47,48]
Americas	Frequency regulation; resilience; fleet electrification; techno-economic evaluations	Texas (ERCOT); California (US); Ontario (Canada)	Interconnection constraints; slow market reforms; inconsistent policies [49,50]
Australia	Consumer preference modeling; EV adoption lag; remote grid resilience	Sydney; Melbourne; regional corridors	Low EV penetration; long-distance travel; limited incentives [35]
Africa	Load-shedding resilience; taxi fleet electrification	Cape Town; Johannesburg (South Africa)	Affordability; limited infrastructure; grid instability [51]
Global reviews	Cross-regional benchmarking; techno-economic barriers	Global scope	Lack of unified protocols; insufficient pilots; revenue uncertainty [41]

The distribution and focus of V2G research by country are visualized in Figure 2, while Table 2 synthesizes regional research foci, emblematic case studies, and characteristic implementation barriers. Together, these overviews highlight the importance of regional policy, infrastructure readiness, and market maturity in shaping the global trajectory of V2G adoption.

3.2. Thematic Trends and Research Evaluation

The evolution of research on V2G and EV integration reveals a clear trajectory: from foundational socio-technical concepts to advanced technical optimization, policy analysis, and AI-enabled system integration. Early work framed V2G as a promising but uncertain socio-technical innovation, while recent studies treat it as a maturing infrastructure and market design problem requiring coordinated engineering, regulatory, and behavioral solutions. The overall publication volume grows steadily from 2009, with a marked surge after 2022, reflecting the shift from conceptual interest to practical deployment and large-scale planning [52,53]. These thematic shifts are also reflected in the yearly article distribution and focus summarized in

Table 3. Early era (2009–2011): foundation and conceptualization. “# Articles” denotes all identified V2G studies.

Year	# Articles	Key Focus/Themes
2009	3	Socio-technical obstacles; RES integration feasibility; PHEV/V2G promise and pitfalls; technical and social barriers [54,55,56]
2010	5	Initial market challenges; immature EV technologies; country-specific context (China) [57,58,59,60,61]
2011	9	Grid interface; load aggregation; V2G control interface standardization (ISO/IEC); distribution grid integration challenges [62,63,64,65,66,67,68,69,70]

,

Table 4. Mid-period growth (2012–2016): technical focus, optimization, and V2X expansion. “# Articles” denotes studies classified under listed themes.

Year	# Articles	Key Focus/Themes
2012	14	System-level integration; demand response; smart grid; intelligent energy management; V2G communication; data mining for DR [71,72]
2013	13	Ancillary services; frequency regulation; V2H/V2V expansion; V2X concept introduction [73,74,75]
2014	30	V2G/RES integration; socio-economic barriers; mobile energy storage; long-term implementation challenges [12,76,77]
2015	31	Hardware modeling; bidirectional converters; stochastic optimization; Volt-VAR optimization; wind integration [78,79,80,81]
2016	25	Privacy; V2G vs. V2H/V2B efficiency; communication standards (WAVE); optimization algorithms [82,83,84,85,86]

Note: Citations are illustrative examples from classified studies.

and

Table 5. Later acceleration and post-2021 explosion (2017–2025): policy, AI, system modeling, hyper-specialization.

Year	# Articles	Key Focus/Themes
2017	38	Economic benefits of V2G; battery SoH/degradation; decentralized RES/EV coordination [87,88,89]
2018	47	Policy mechanisms; ancillary services; bidirectional hardware; power conversion modeling [90,91,92,93]
2019	48	AI/ML optimization; intelligent energy management; wireless charging/shared mobility synergies [94,95,96]
2020	53	Stochastic modeling; V2G/PV self-consumption; gas system/VRES integration [97,98,99]
2021	66	Regulatory barriers; business models; RL charging; distributed computing [25,100,101,102]
2022	117	V2X definition; cybersecurity; smart charging; battery degradation; microgrid resilience [103,104,105,106]
2023	95	Advanced AI (RL/DL); economic incentives; battery wear; microgrid services; V2X alternatives [107,108,109]
2024	207	User acceptance; DRL algorithms; blockchain; non-traditional V2X applications [110,111,112]
2025	183	Digital twin; real-time BMS; disaster recovery; extreme fast charging; AI/cybersecurity [113,114,115]

Note: “# Articles” denotes classified studies per theme; citations illustrative examples.

.

3.2.1. Early Era (2009–2011): Foundation and Conceptualization

During this period, research laid the conceptual groundwork for V2G, exploring the feasibility of using EVs as flexible storage and identifying technical and socio-cultural barriers. Studies addressed the integration of electrified vehicles with variable renewable energy sources. They touched on business, political, and cultural impediments, and Sovacool (2009) is particularly influential here as one of the first socio-technical analyses of V2G barriers [54,55]. Initial market challenges in various countries, such as China, emerged alongside technical goals and immature technologies [57]. Research also focused on grid interface standardization, load aggregation, and the introduction of EVs into distribution networks [62,63].

3.2.2. Mid-Period Growth (2012–2016): Technical Focus and Expanding V2X Scope

As V2G gained acceptance, research expanded toward detailed technical feasibility and system-level modeling. Comprehensive surveys addressed smart grid integration, demand response programs, and communication requirements for coordinated charging [71,72]. The core role of EVs in ancillary services such as frequency regulation was explored, alongside the emergence of V2H and V2V, extending the concept to V2X [76,77]. Non-technical challenges such as privacy, revenue models, and investment barriers were increasingly acknowledged, highlighting the long-term nature of large-scale V2G implementation [12]. Technical work focused on advanced hardware and optimization techniques, including bidirectional converters and Volt-VAR optimization [78,79,80,81], with privacy concerns and communication standards becoming prominent topics [82,83,84,85,86]. To avoid overloading the narrative with long citation lists, Table 4 reports the number of studies per theme and highlights representative examples; the full list of classified articles is available in the underlying dataset.

3.2.3. Later Acceleration (2017–2021): Policy, AI, and Advanced System Modeling

Research shifted toward economic analyses, policy mechanisms, and the application of AI/ML techniques for uncertainty and optimization. Key themes included economic valuation of V2G services, battery degradation impacts, and decentralized control strategies for renewable coordination [87,88,89]. Regulatory frameworks and standardization were critically examined [90], accompanied by modeling of bidirectional charging hardware [92,93]. AI and machine learning were applied for energy management and system synergy, integrating V2G with wireless charging and shared mobility [94,95,96]. Research also extended into stochastic system planning and integration with natural gas systems, focusing on urban district renewable self-consumption [97,98,99]. The importance of addressing regulatory barriers, mature business models, and scalable ICT solutions was underscored [25,100,101,102]. Table 5 complements the text by mapping the yearly growth in articles to key themes and representative studies, allowing readers to trace how technical, policy, and AI-related topics gain prominence over time.

3.2.4. Post-2021 Explosion: Hyper-Specialization and Multidisciplinary Integration

The post-2021 period marks a phase of hyper-specialization with strong multidisciplinary integration. Foundational works consolidated the V2X concept and offered comprehensive barrier classifications [45,103,104,105], while cybersecurity vulnerabilities associated with protocols such as OCPP and broader IoT integration rose to prominence [106,116]. Contributions examined how smart charging can mitigate power quality issues and introduced decentralized optimization approaches to cope with uncertain EV driving patterns [117,118,119,120]. Battery degradation modeling and microgrid resilience strategies also gained focus [121,122]. Together, these studies treat V2G as part of a maturing cyber-physical infrastructure rather than a purely experimental add-on.

In 2023, research efforts concentrated on resolving tensions between economic incentives and battery wear, adopting advanced AI techniques such as deep and reinforcement learning for efficient scheduling and load management [108,123]. Policy and regulatory considerations drove discussions on tariff designs and market mechanisms [109,124,125]. The role of V2G in primary frequency control and microgrid services, as well as the exploration of alternative V2X applications like shared autonomous electric vehicles and battery swapping stations, expanded [126,127,128,129].

In 2024, research shifted toward deepening understanding of user acceptance, exploring specialized hardware solutions such as bidirectional onboard chargers and multi-port smart transformers, and leveraging blockchain for decentralized and secure energy trading [110,111,112,130,131,132]. Novel applications, including integration within airport ground vehicle fleets and repurposing gas stations for fast charging, illustrate the technology’s broadening scope [132,133].

By 2025, emerging work has focused on resilience via mobile power applications for disaster recovery, digital-twin-enabled battery management, and large-scale system planning that incorporates extreme fast charging and high-voltage technologies [113,114,115]. AI and cybersecurity studies continue to address vulnerabilities in protective algorithms and blockchain infrastructures, alongside the socio-technical dimensions of user behavior and perceived cyber risk [134,135,136,137]. The full set of post-2021 studies and themes is summarized in Table 5, which reports yearly article counts and representative examples.

3.2.5. Summary of Changes Throughout the Years

Taken together, the yearly patterns highlight four broad phases in V2G research, evolving from conceptual exploration to questions of commercial deployment. From 2009–2014, work was dominated by conceptual curiosity and technical modeling, establishing basic feasibility and early socio-technical debates. Between 2015 and 2018, research shifted towards multi-system V2X integration, bringing in issues such as cybersecurity, market design, and emerging non-technical concerns. The 2019–2021 period was characterized by an optimization-to-AI transition, with advanced control and forecasting techniques layered onto increasingly complex system models. Since 2022, a growing share of studies has focused on commercial viability, highlighting policy design, consumer behavior, and regulatory frameworks as decisive factors for large-scale deployment.

Table 3, Table 4 and Table 5 summarize themes and studies per year based on the coded corpus. For 2009–2011, all identified V2G implementation articles are shown; from 2012 onward, the column “# Articles” reports the number of studies classified under the indicated themes, while the citations in the third column provide representative examples (the full list is available in the underlying dataset). Regional patterns show Europe prioritizing market design and regulation, with a substantial share of European implementation-critical studies coded with primary levers in the business–economic and governance–policy domains. Several Asian countries focus more strongly on infrastructure gaps and large-scale integration, with many Asian studies emphasizing infrastructure and ecosystem issues. These regional emphases are descriptive of the coded literature rather than exhaustive; they reflect where existing V2G studies concentrate attention rather than a complete ranking of all underlying drivers.

Overall, the trajectory from technical optimization dominance to the recognition of policy, market, and behavioral bottlenecks suggests that non-technical factors are widely perceived as primary constraints on V2G commercialization in the reviewed literature. These descriptive insights motivate the four-domain socio-technical framework introduced in Section 4 and provide the empirical basis for deriving domain-specific transition levers and realistic 2040 targets in Section 5.

4. Four-Category Framework for V2G Implementation

Figure 3 presents the four non-technical domains: business (economic), governance/policy, social, and infrastructure and ecosystem. These domains systematically emerged from coding the 974-article corpus. This section goes beyond previous V2G and EV integration reviews by using the coded implementation literature (95 non-technical and mixed studies) to formalize an explicitly non-technical framework for V2G deployment. Whereas earlier reviews typically list technical, economic, and policy barriers at an aggregate level, the four socio-technical domains are clustered so that they can be directly linked to transition levers and, in Section 5, to indicative KPIs and regional transition pathways.

4.1. Business (Economic)

Economic feasibility is a dominant concern in V2G research, with many studies identifying fragile or incomplete business models that insufficiently engage aggregators, grid operators, and EV users [6,41]. A widely cited example is the work by Sabadini and Madlener, who empirically test the common belief that double taxation destroys the V2G business case and show that, under realistic German conditions, profitable operation for frequency regulation is still possible [11]. Such results challenge received industry wisdom and are directly relevant for regulators designing tariff structures. More broadly, financial incentives such as dynamic pricing often remain too weak or uncertain to motivate participation [13,138], while high bidirectional infrastructure costs can exceed anticipated revenues from grid services [139]. Effective market integration requires mature settlement systems and clearly defined products for V2G services, which are still underdeveloped in most contexts [6,140].

4.2. Governance/Policy

Governance and policy studies highlight fragmented regulatory frameworks and limited recognition of aggregators and flexibility providers as formal market actors [16,141]. Foundational works such as San Román et al. provided some of the earliest systematic treatments of the V2G market structure, introducing the EV aggregator role and clarifying how responsibilities and revenues could be allocated across actors in liberalized electricity markets [69]. Subsequent analyses show that gaps and inconsistencies in standardization—particularly around ISO 15118 [142] OCPP [143], and related specifications—constrain interoperability and create uncertainty for investors [16,144]. Governmental incentives are frequently complicated by taxation structures, including double taxation of V2G power flows, which weaken business cases and slow deployment [11,90].

4.3. Social

On the social side, consumer acceptance is hindered by fears of battery degradation [110,145], range anxiety [16,146], data privacy concerns [147,148], and reluctance to relinquish control over charging to third parties [110,146]. Bakhuis et al. provide one of the clearest quantitative rankings of perceived barriers, showing that loss of flexibility and control over vehicle availability is often a more salient concern than battery wear, even when users are explicitly informed about degradation risks [110]. Several studies therefore emphasize the importance of understandable contracts, transparent communication of risks and benefits, and user-configurable participation options as prerequisites for sustained engagement.

4.4. Infrastructure and Ecosystem

Infrastructure and ecosystem analyses show that V2G deployment depends on the availability and reliability of bidirectional chargers, as well as on grid and ICT infrastructures capable of handling bidirectional power flows and associated data streams [16,144,149]. Early technical work, such as Heuer et al., already identified the critical role of ISO/IEC-compatible interfaces for distribution-grid integration of EVs, highlighting how standardized communication and control are prerequisites for scalable V2G operation [63]. More recent studies confirm that distribution networks must manage the voltage and congestion impacts of V2G operations [150,151], while coordination among OEMs, charge point operators, utilities, municipalities, and other actors remains challenging [12,152]. Misaligned incentives and fragmented responsibilities at the ecosystem level often translate into slow and uneven roll-out.

Some issues, such as interoperability, trust, data governance, or market coordination, span multiple domains. To avoid double-counting, we assigned each coded barrier or enabler to the domain that best reflected the primary lever of change. For example, OCPP-related cyber-security vulnerabilities are mapped to Infrastructure and Ecosystem when they primarily concern charger and network architecture, to Governance/Policy when they relate to formal protocol mandates and roles in market rules, and to Social when they are discussed in terms of user trust in data handling. Market coordination failures and value-chain misalignments without a predominant regulatory or infrastructural component were placed in the Business/Economic domain. Appendix C illustrates this rule for several multi-domain concepts.

In summary, synthesizing 974 articles from 2009 to 2025 across diverse geographies, the coded literature consistently supports these four domains as a comprehensive and practical basis for understanding the multifaceted challenges and opportunities shaping V2G deployment worldwide. The next section moves from describing barriers within each domain to identifying concrete transition levers and indicative 2040 targets.

5. From Barriers to Transition Levers by Domain

The descriptive results above show how V2G research has expanded across regions and themes, and how non-technical issues have become more prominent over time. In this section, the four socio-technical domains are reinterpreted not only as sites of barriers, but as transition levers that can realistically be adjusted by 2040 in support of sustainable V2G deployment. Rather than asking only which obstacles exist, the analysis focuses on what can change in each domain, by whom, and with which indicative KPIs.

5.1. Business/Economic: Revenue Models and Risk Allocation

Building on the barriers summarized in Section 4, business-related studies across Europe, the Americas, and parts of Asia consistently highlight fragile or incomplete V2G value propositions, missing multi-actor revenue models, and uncertain profitability once infrastructure and battery wear are accounted for [6,11,139,153]. Urban V2G pilots further reveal that current metering and settlement systems often cannot allocate revenues transparently across aggregators, DSOs, and EV users, reinforcing these business barriers [6,153,154]. Against this background, three main transition levers emerge that can realistically be adjusted by 2040.

• Multi-actor revenue-sharing mechanisms.

Several empirical and modeling studies show that V2G business cases become more robust when revenues are explicitly shared between aggregators, DSOs/TSOs, retailers, and EV users, for example via stacked services or long-term contracts [6,153]. Sabadini and Madlener (2025) provide a critical reference point here by demonstrating that, even under existing German taxation rules, V2G for frequency regulation can remain profitable when revenue streams are allocated transparently across actors [11]. These findings suggest that the design of multi-actor contracts is at least as important as the absolute level of tariffs. An indicative KPI for this lever is the fraction of V2G pilots or programs that implement explicit multi-actor revenue-sharing contracts.

• Risk-sharing instruments for degradation and price volatility.

Work on user acceptance and techno-economic constraints indicates that perceived downside risks—battery wear, uncertain remuneration, exposure to volatile prices—often dominate willingness to participate [87,110,145]. Bakhuis et al. show, for example, that users are more willing to enroll in V2G schemes when contracts include guarantees on minimum state of charge or explicit compensation for additional degradation [110]. Proposed instruments include guaranteed minimum payments, degradation compensation clauses, and insurance-like products that cap user exposure to extreme events. Relevant KPIs include the proportion of V2G offers that incorporate explicit degradation or risk-compensation terms and measured changes in stated willingness to participate over time.

• Tariff and product design for V2G services.

A third lever concerns how V2G is embedded into wider tariff and market structures. Studies on flexibility markets and capacity mechanisms suggest that treating V2G as a distinct product—rather than as generic consumption—improves both valuation and integration [13,100,155]. Venegas and Petit (2021), for instance, show how active EV participation in distribution-level flexibility markets depends on clearly specified products and settlement rules [100]. By 2040, aligning tariffs with flexibility services (e.g., capacity, ramping, congestion relief) rather than pure energy volumes is a realistic target. Indicative KPIs include the share of electricity markets that list a defined V2G or EV-flexibility product and the number of contracts or tenders explicitly remunerating V2G services.

Taken together, studies such as Sabadini and Madlener (2025) explicitly quantify how taxation, tariff structures, and revenue allocation shape V2G profitability, and we code these findings as evidence for the levers multi-actor revenue sharing and risk-sharing instruments, which are operationalized in KPIs such as the presence of V2G-specific tax and tariff instruments and the share of pilots using explicit revenue-sharing contracts [11,153].

5.2. Governance/Policy: Roles, Rules, and Standardization

Governance and policy studies underline fragmented regulatory frameworks, slow recognition of aggregators, and inconsistent treatment of bidirectional charging across jurisdictions [16,90,100]. Evidence from pilots shows that aggregators frequently operate without clear legal recognition and that DSO/TSO frameworks are not yet configured for multi-role participation, creating uncertainty around responsibilities and revenue allocation [11,16]. Against this background, three related levers can realistically be activated by 2040.

• Formal recognition of aggregators and flexibility providers.

Foundational works such as San Román et al. provide some of the earliest systematic treatments of V2G market structure, introducing the EV aggregator role and clarifying how responsibilities and revenues can be allocated in liberalized electricity markets [69]. Building on this, more recent studies and pilot evaluations show that where aggregators are formally recognized, EV fleets can participate in balancing, capacity, and local flexibility markets on a non-discriminatory basis [11,100]. An indicative KPI for this lever is the number of jurisdictions that define an aggregator or flexibility-provider role in legislation or market rules, together with the share of markets in which such actors are eligible to bid on behalf of EV fleets.

• Protocol and interoperability mandates.

A second lever concerns the codification of technical standards into regulatory requirements. Studies focusing on ISO 15118, OCPP, and related specifications show that harmonized protocols are a precondition for interoperable V2G services across vehicle brands, chargers, and system operators [16,106,144]. Without such mandates, uncertainty about future compatibility undermines private investment. Here, relevant KPIs include the share of bidirectional chargers certified under agreed communication and grid interconnection standards, and the presence of explicit interoperability clauses for V2G in grid codes or connection rules.

• Taxation and regulatory reform.

Third, taxation and energy-market rules have a decisive influence on the V2G business case. Sabadini and Madlener (2025) empirically test the widely held belief that double taxation makes V2G unprofitable and show that, in the German context, profitable operation is still achievable under current rules, but would be significantly improved by targeted reforms [11]. Other studies point to mismatches between tariff structures and flexibility value [90,153]. By 2040, the removal of double taxation for V2G power flows and the alignment of tariffs with flexibility services rather than pure volumetric consumption are realistic policy goals. KPIs here include the number of jurisdictions that have removed double taxation for V2G, as well as the existence of explicit V2G provisions in market design reforms, tax codes, and network tariffs.

In combination, San Román et al.’s early market-structure analysis and more recent pilot evaluations on aggregator access and protocol requirements provide the empirical basis for the governance levers identified here, formal recognition of aggregators, protocol and interoperability mandates, and taxation and regulatory reform, which translate directly into KPIs such as the number of jurisdictions recognizing aggregators, the share of chargers certified under common standards, and the removal of double taxation for V2G power flows [11,16,69,100,144].

5.3. Social: Trust, Control, and Everyday Practices

Social research points to recurring concerns about battery degradation, range anxiety, data privacy, and perceived loss of control over charging [14,110,146,147,148]. Pilots confirm that privacy-by-design systems and transparent user interfaces explaining V2G participation and override options are often missing, making it difficult for EV owners to assess data-sharing risks versus grid-service benefits and eroding the trust essential for widespread adoption [14,110,154]. Within this domain, transition levers center on how users experience and govern their participation in V2G.

• User-centric participation models.

Several studies indicate that willingness to enroll in V2G programs increases when users can configure clear limits on state of charge, time windows, and minimum range, and retain simple override options [14,110,146]. Bakhuis et al. in particular provide a ranked list of perceived barriers and demonstrate that loss of flexibility and control over vehicle availability often outweighs concerns about battery wear [110]. An indicative KPI for this lever is the share of pilots and commercial offers that provide user-configurable participation profiles, alongside observed retention rates in such schemes.

• Privacy-by-design data architectures and consent management.

A second lever concerns how data are collected, processed, and shared. Work on privacy-preserving architectures and consent mechanisms indicates that clear data flows, local processing, and granular consent options can mitigate user concerns [106,147,148]. Nonetheless, many pilots still rely on opaque data practices. Relevant KPIs include the proportion of V2G systems that implement privacy-by-design principles (e.g., minimization, local aggregation, pseudonymization) and measured changes in user-reported privacy concerns over time.

• Communication and co-design processes.

Finally, long-term field trials, living labs, and participatory design exercises have been shown to support trust building and the alignment of V2G services with everyday mobility practices [37,90,156]. These processes allow users and local stakeholders to shape tariffs, contracts, and interface designs, rather than being passive recipients. KPIs here include the number of projects that employ co-design or living lab approaches, as well as survey-based indicators of perceived fairness, understanding, and satisfaction with V2G participation.

Quantitative barrier rankings from Bakhuis et al., longitudinal acceptance studies such as those by Kester et al., and privacy-focused work by Zhang et al. and Shang et al. underpin the social levers user-centric participation models, privacy-by-design data architectures, and communication and co-design processes, which we operationalize through KPIs such as the share of offers with user-configurable profiles, the implementation of privacy-by-design principles, and user retention and satisfaction rates in V2G programs [14,110,147,148].

5.4. Infrastructure and Ecosystem: Hardware, Networks, and Coordination

Infrastructure and ecosystem work shows that V2G deployment depends on the availability of bidirectional chargers, suitable communication and control infrastructures, and coordinated investment across utilities, cities, and mobility providers [16,149,150,154,157]. Urban pilots in heterogeneous environments confirm that insufficient bidirectional charger networks and immature coordination architectures between EVs, chargers, optimizers, and grid-monitoring systems are key constraints on scaling beyond demonstrations [18,154,157]. Three realistic levers by 2040 stand out in this domain.

• Targeted build-out of bidirectional charging infrastructure.

Rather than uniform deployment, several studies argue for concentrating bidirectional chargers in high-impact locations such as depots, mobility hubs, constrained distribution grids, and critical facilities [35,47,150]. This approach maximizes system benefits while containing costs. A straightforward KPI is the share of public and private charging points that are bidirectional-capable in these priority locations relative to the overall charging network.

• Integrated planning of grid and mobility infrastructures.

A second lever involves embedding V2G explicitly into distribution network planning, urban development strategies, and resilience plans. Planning studies show that treating EVs as flexible grid assets, rather than exogenous loads, can change investment and reinforcement decisions [16,97,158]. KPIs here include the number of planning processes, tenders, or policy documents that explicitly reference V2G or EV flexibility, and the frequency with which distribution system operators and city planners jointly consider V2G scenarios.

• Ecosystem coordination mechanisms.

Finally, coordination across OEMs, charge-point operators, DSOs/TSOs, aggregators, municipalities, and ICT providers is critical but often under-institutionalized [12,41,152]. Documented mechanisms include public–private partnerships, platform governance arrangements, and formal data-sharing agreements. Relevant KPIs comprise the presence of established multi-stakeholder coordination bodies or platforms in a given jurisdiction, the number of signed data-sharing or interoperability agreements, and evidence of jointly governed V2G platforms in operation.

Empirical evidence from technical integration studies (Heuer et al. [63] and Cupan et al. [150]), urban case studies such as Shanghai (Zhang et al. [18]), and pilot architectures in Dresden (Wang et al. [154]) directly motivates the infrastructure levers targeted build-out of bidirectional charging, integrated grid–mobility planning, and ecosystem coordination mechanisms, which we capture through KPIs such as the share of bidirectional chargers in priority locations, the inclusion of V2G in planning processes, and the presence of formal multi-stakeholder coordination platforms [18,63,150,154].

Taken together, these four domains and associated levers provide a structured design space for non-technical V2G implementation. Figure 4 summarizes the domains and levers in a configurator-style diagram, highlighting the main design choices (e.g., revenue sharing, aggregator role, participation model, charger siting) that recur across the 95 implementation-focused studies.

Beyond the domain-level discussion above, Table 6 synthesizes a subset of the proposed non-technical KPIs, indicating how they can be calculated and applied in practice when monitoring V2G deployment.

Table 6. Illustrative non-technical KPIs derived from the coded implementation literature.

Domain	KPI	Indicative Calculation	Example Use Case
Business and Economic	Markets with defined V2G products	Share of electricity markets offering dedicated V2G or EV-flexibility products	Tracking transition from pilot projects to standardized market offerings
	Pilots with multi-actor revenue sharing	Share of pilots using explicit revenue-sharing across aggregators, system operators, retailers, and EV users	Assessing whether value capture extends beyond single actors
Governance and Policy	Jurisdictions recognizing aggregators	Share of jurisdictions with formal aggregator or flexibility-provider roles in regulation	Monitoring regulatory progress toward market access for aggregators
	V2G in grid codes or tariffs	Binary indicator of explicit V2G provisions in grid codes, market rules, or taxation frameworks	Assessing formal integration of V2G into regulatory instruments
Social	User-configurable participation	Share of offers allowing user-defined SoC limits, time windows, or override options	Evaluating adoption of user-centric participation models
	User retention in programs	Share of enrolled users remaining active after a defined period (e.g., 12 months)	Measuring sustained acceptance beyond initial enrolment
Infrastructure and Ecosystem	Bidirectional chargers in priority locations	Share of bidirectional chargers deployed at hubs, depots, or constrained grid areas	Assessing targeted infrastructure deployment in high-impact contexts
	Planning processes including V2G	Share of grid or urban planning documents explicitly considering V2G integration	Tracking inclusion of V2G in planning and investment decisions

Table 6. Illustrative non-technical KPIs derived from the coded implementation literature.

Domain	KPI	Indicative Calculation	Example Use Case
Business and Economic	Markets with defined V2G products	Share of electricity markets offering dedicated V2G or EV-flexibility products	Tracking transition from pilot projects to standardized market offerings
	Pilots with multi-actor revenue sharing	Share of pilots using explicit revenue-sharing across aggregators, system operators, retailers, and EV users	Assessing whether value capture extends beyond single actors
Governance and Policy	Jurisdictions recognizing aggregators	Share of jurisdictions with formal aggregator or flexibility-provider roles in regulation	Monitoring regulatory progress toward market access for aggregators
	V2G in grid codes or tariffs	Binary indicator of explicit V2G provisions in grid codes, market rules, or taxation frameworks	Assessing formal integration of V2G into regulatory instruments
Social	User-configurable participation	Share of offers allowing user-defined SoC limits, time windows, or override options	Evaluating adoption of user-centric participation models
	User retention in programs	Share of enrolled users remaining active after a defined period (e.g., 12 months)	Measuring sustained acceptance beyond initial enrolment
Infrastructure and Ecosystem	Bidirectional chargers in priority locations	Share of bidirectional chargers deployed at hubs, depots, or constrained grid areas	Assessing targeted infrastructure deployment in high-impact contexts
	Planning processes including V2G	Share of grid or urban planning documents explicitly considering V2G integration	Tracking inclusion of V2G in planning and investment decisions

5.5. Regional Variation in Transition Routes

The same levers do not activate uniformly across regions. As Section 3 showed, Europe focuses on business models and regulation, Asia on infrastructure scaling, and the Americas on services and resilience [35,41,47,49,51,153]. In practice, this suggests three stylized transition routes. Regulation-led pathways are more likely in European contexts, where market design, taxation reform, and aggregator recognition dominate the governance agenda. Infrastructure-first pathways are more typical in several Asian and Middle Eastern countries, where large-scale charging and grid upgrades are the primary focus, with business models and social practices catching up. Service-driven pathways emerge in parts of the Americas, where V2G is framed as a resilience or ancillary service, and business models for specific services (for example, frequency regulation) drive experimentation.

These regional emphases motivate the archetypal pathways formalized in the subsequent roadmap section and highlight why a one-size-fits-all sequence of levers is unlikely to succeed.

6. A V2G Sustainability Roadmap

Building on the transition levers in Section 5, this section outlines a sustainability roadmap for V2G grounded in a deep-dive subset of 95 non-technical and mixed studies. These studies include pilots, field trials, business model experiments, and policy analyses that explicitly bridge technical, policy, business, and social strands and involve multiple actor groups such as utilities, OEMs, municipalities, ICT providers, and users [41,90,154,156]. Together, they provide concrete examples of how the four domains can be operationalized in practice and how socio-technical silos can be overcome.

6.1. Bridging Practices in the 95 Deep-Dive Studies

Across the 95 deep-dive studies, several recurring bridging practices stand out. Many projects employ mixed methods that combine quantitative system modeling with qualitative stakeholder interviews, workshops, or surveys, allowing technical feasibility to be assessed alongside policy, business, and social acceptability [41,90]. Field trials and living labs use real charging data and user feedback to co-design tariff structures, contracts, and control strategies, thereby linking business models and user practices in concrete settings [37,156]. Policy-oriented case studies analyze how specific regulatory reforms, incentives, or market designs shape V2G opportunities and risks, often comparing multiple jurisdictions or regulatory options [38,100]. Finally, several urban demonstrators and district-scale pilots highlight the importance of cross-sector coalitions—bringing together city authorities, network operators, mobility providers, and technology firms—to align infrastructure investments, data-sharing arrangements, and service offerings [154,158].

These bridging practices illustrate how combinations of methods (e.g., mixed methods, participatory design, business model experimentation, policy analysis) and actor constellations (e.g., utilities plus municipalities plus OEMs and ICT providers) can move V2G beyond purely technical optimization towards socio-technical integration. They also provide empirical grounding for the archetypal transition pathways and KPIs proposed below.

6.2. Three Archetypal V2G Transition Pathways

Synthesizing the domain-level levers and the 95 deep-dive cases, three archetypal V2G transition pathways are identified that capture dominant regional emphases while remaining general enough to be adapted elsewhere.

Regulation-led Europe: In many European contexts, V2G progress is closely tied to regulatory reform, market design, and taxation changes [11,16,153]. Here, the main transition levers lie in the Governance/Policy and Business/Economic domains: formal recognition of aggregators and flexibility providers, protocol and interoperability mandates, and the removal of double taxation, combined with multi-actor revenue-sharing models and tariff products that reward flexibility [90,100]. Non-technical KPIs for this pathway include the number of markets with recognized aggregator roles, the share of bids or contracts that explicitly remunerate V2G services, and the presence of V2G-relevant provisions in grid codes and national or EU-level regulatory frameworks. A successful regulation-led pathway is likely to enhance system resilience and decarbonization trajectories by creating predictable conditions for investment, but it must also attend to distributional effects and equity in access to V2G-enabled services.

Infrastructure-first Asia/Middle East: Several Asian and Middle Eastern countries emphasize large-scale charging and grid infrastructure deployment, often linked to broader decarbonization and urbanization strategies [18,47,48]. Here, the primary levers sit in the Infrastructure and Ecosystem and Business/Economic domains: targeted build-out of bidirectional charging at high-value locations, integration of V2G into distribution and urban planning, and coordination mechanisms that align utilities, developers, and mobility operators [97,150,158]. KPIs for this pathway include the penetration of bidirectional chargers among public and private charging points, the number of planning processes or tenders that explicitly reference V2G, and the existence of formal collaboration agreements or platforms linking key ecosystem actors. An infrastructure-first trajectory can accelerate decarbonization and support new mobility services, but it risks lock-in if business models and user engagement strategies are not developed in parallel.

Service-driven Americas: In parts of North and South America, V2G is often framed as a means to deliver specific services such as frequency regulation, peak shaving, or resilience for critical loads and fleets [32,49,50]. This “service-driven” pathway relies on levers in the Business/Economic and Social domains—development of service-specific business models for grid support and resilience, coupled with user-centric participation models for fleets, households, and communities [110,155]. Relevant KPIs include the number and volume of V2G-based service contracts (e.g., for frequency regulation or resilience), measured user acceptance and retention in service programs, and documented contributions of V2G to outage management or critical infrastructure support. In terms of sustainable futures, a service-driven pathway can strengthen resilience and enable new mobility offerings, but must be carefully designed to avoid reinforcing existing inequalities in who benefits from such services.

These three pathways are stylized rather than prescriptive. They show how different combinations of domain-level levers can structure V2G transitions and how regional contexts shape the sequencing and emphasis of interventions. In practice, hybrid pathways and cross-regional learning will be essential to align V2G deployment with broader goals of system resilience, decarbonization, mobility service innovation, and social equity.

6.3. Non-Technical KPIs for Sustainable Futures

Across pathways, a minimal set of non-technical KPIs can support monitoring of V2G’s contribution to SDG 7 and SDG 13 and to wider sustainable futures [16,41,100]. At the Business/Economic and Governance/Policy levels, key indicators include the share of electricity markets with recognized aggregator roles, the number of products or programs that explicitly remunerate V2G flexibility, the prevalence of revenue-sharing contracts, and the removal of double taxation or similar barriers [11,153]. In the Social domain, KPIs comprise empirically measured user-acceptance thresholds, participation and retention rates in V2G schemes, and longitudinal changes in privacy concerns and perceived control [14,110,147]. For Infrastructure and Ecosystem, indicative KPIs include the penetration of bidirectional chargers, the share of planning processes that integrate V2G, and the number of formal ecosystem coordination mechanisms linking utilities, OEMs, cities, and ICT providers [41,150,152].

These indicators provide a bridge from the global literature to ex-post evaluation of concrete pilots and programs. They can be applied not only to existing V2G projects but also to forthcoming urban demonstrators such as MOBILITIES for EU, where they can help assess which non-technical levers have been activated, where gaps remain, and how V2G contributes to more resilient, low-carbon, and equitable energy and mobility systems.

7. Limitation, Implications, and Future Research

This systematic review reveals persistent non-technical barriers across all 974 articles, confirming the validity and usefulness of the four-domain framework. However, important gaps and limitations remain. First, although two coders applied a shared rubric and resolved disagreements by consensus, we did not calculate a quantitative inter-coder reliability statistic; this consensus-based procedure is common in qualitative and mixed-methods synthesis but may still leave room for subjective judgment in borderline classifications. Second, no formal sensitivity analysis was performed for the abstract-score threshold used to select the 164 high-relevance papers. Exploratory re-screening of borderline cases suggested that stricter thresholds would mainly exclude clearly peripheral mentions of V2G, but future work could systematically examine how different cutoffs affect recall and the balance between technical and non-technical studies.

These gaps persist across regions—such as Europe’s emphasis on regulatory design, Asia’s infrastructure challenges, and the United States’ focus on frequency services—indicating the need for integrated, context-sensitive solutions. On the business side, there is a lack of validated multi-stakeholder revenue models that integrate aggregators, DSOs, and users across different regulatory and market environments. Governance and policy studies seldom provide systematic comparative analyses of regulatory harmonization (for example, between the EU, Asia, and the US) or of protocol interoperability choices (such as ISO 15118 versus OCPP) and their implications. Social research remains limited in terms of longitudinal evidence on how user behavior, trust, and risk perceptions evolve over time and under different contractual arrangements. Infrastructure and ecosystem work rarely tests the real-world scalability of bidirectional charger networks and grid-edge coordination under realistic operational constraints.

Building on the baseline established in this article, an immediate next step is a more granular coding of the 95 primarily non-technical papers to map specific drivers and enablers within each of the four categories. This deeper analysis would extend the four-domain socio-technical framework into a more detailed technology-transfer framework that positions sustainability, rather than purely technical feasibility, as the ultimate success metric for V2G deployment. The KPIs and transition pathways proposed in Section 6 provide initial building blocks for this further operationalization.

Beyond this, a broader research roadmap for non-technical V2G advancement includes several directions. First, the four-domain framework should be validated and refined in emerging markets such as Africa and South Asia, where grid conditions, mobility patterns, and institutional contexts differ markedly from those in early-adopting regions. Second, region-specific barrier mitigation strategies are needed—for example, tailored approaches to managing load-shedding contexts in South Africa or long-distance corridors in Australia. Third, applying the proposed non-technical KPIs to pilot-to-deployment transitions would help evaluate and compare V2G initiatives across projects and jurisdictions in a consistent way. The four-domain socio-technical framework proposed here is evidence-based but evolving: it reflects V2G implementation research up to 2025 and will benefit from refinement as new large-scale pilots and longitudinal studies become available.

A further limitation is that no formal sensitivity analysis was performed for the abstract-score threshold used to select the 164 high-relevance papers. Exploratory re-screening of borderline cases indicated that stricter thresholds would mainly exclude clearly peripheral mentions of V2G, but future work could systematically examine how different cutoffs affect recall and the balance between technical and non-technical studies.

Although V2G is the worked example in this article, the framework and roadmap may also generalize to other distributed flexibility options, such as broader V2X concepts, stationary storage, or heat pumps, where similar constellations of business, governance, social, and infrastructure factors shape deployment trajectories. In all cases, communication and digital infrastructures appear as critical enablers of data exchange and coordination, but not as sufficient conditions for transition; technical connectivity must be aligned with the non-technical levers identified in this review. Together, these directions leverage the comprehensive baseline provided here to guide future empirical, modeling, and policy work, with the aim of accelerating practical, sustainable deployment of V2G and related flexibility solutions worldwide. Future work can build on the 95 non-technical-primary studies identified here to present a detailed coding and analysis, operationalize the proposed KPIs and pathways into an applied technology-transfer framework, and validate it on concrete pilots such as MOBILITIES for EU [5].

8. Conclusions

This systematic review of 974 V2G articles (2009–2025) suggests four non-technical domains—Business/Economic, Governance/Policy, Social, and Infrastructure and Ecosystem—as critical determinants of scalable deployment. Temporal trends reveal accelerating multidisciplinary integration after 2021, while regional analyses highlight context-specific priorities, with Europe emphasizing regulatory design and market rules, several Asian countries focusing on infrastructure and large-scale integration, and the Americas concentrating on service provision and resilience [41,47,49,153]. Together, these patterns show that non-technical factors, rather than technical feasibility, now form the primary bottleneck for V2G commercialization.

By structuring these factors into a four-domain framework and linking them to domain-specific transition levers and indicative KPIs, the article moves beyond barrier catalogues towards a technology-transfer roadmap. The three archetypal pathways identified—regulation-led, infrastructure-first, and service-driven—illustrate how different combinations of policies, business models, infrastructures, and user practices can shape V2G deployment trajectories across regions [16,100,110]. The associated KPIs provide a basis for monitoring how V2G contributes to SDG 7 (Affordable and Clean Energy), SDG 13 (Climate Action), and broader goals of resilience, mobility service innovation, and equity.

The review also identifies several gaps that require attention:

• A lack of validated multi-stakeholder revenue models and risk-sharing mechanisms for V2G services;
• Limited comparative governance studies across regulatory regimes and market designs;
• Scarce longitudinal social research on user acceptance, trust, and everyday mobility practices; and
• Few large-scale tests of infrastructure and ecosystem coordination in real distribution grids and urban districts.

Addressing these gaps will require integrated, context-sensitive studies that combine engineering, economics, policy analysis, and social science, ideally in collaboration with system operators, aggregators, OEMs, and cities. The framework, pathways, and KPIs proposed here can support the design and evaluation of such studies and of concrete pilots. Overall, the article aims to help researchers, practitioners, and policymakers move V2G from pilots to large-scale contributions to sustainable energy and mobility futures.