Green Shipping Corridors: A Bibliometric Analysis of Policy, Technology, and Stakeholder Collaboration

Abstract

This study provides a bibliometric review of 238 studies on the concept of green shipping corridors in the maritime industry, published in 93 academic outlets and authored by 654 scholars. Bibliographical data were extracted from the Web of Science database and analyzed using the bibliometrix package in R software (version 4.3.3) alongside VOSviewer (version 1.6.20). Based on citation analysis metrics, the most influential articles, journals, authors, institutions, and countries within the field were identified. Utilizing the bibliographic coupling methodology in VOSviewer, the following four underlying research clusters were distinguished: (1) Sustainable Green Shipping Practices and Research, (2) Alternative Fuels and Low-Carbon Strategies for Maritime Transport, (3) Green and Low-Carbon Maritime Development, and (4) Environmental Sustainability in Maritime Shipping. Content analysis results highlighted crucial policy recommendations, technological adaptation strategies, and collaborative stakeholder practices, providing robust insights for academia and industry practitioners seeking strategic guidance for effective maritime decarbonization via integrated green shipping corridor initiatives.

1. Introduction

Maritime shipping constitutes a fundamental role in the global economy, facilitating approximately 90% of international trade transportation [1]. Carbon emissions from maritime shipping contribute to 2.89% of global greenhouse gas emissions [2]. This environmental impact is further emphasized by data showing that the maritime sector’s emissions increased from 977 million tons in 2012 to 1076 million tons in 2018, indicating a 9.6% increase (IMO, 2021) [3].

Multiple initiatives by international organizations are currently focused on solving the issue of greenhouse gas (GHG) emissions generated by maritime transport, such as (1) IMO’s MEPC.304(72) Resolution [4]; (2) IMO’s MARPOL Annex VI [5]; (3) The Fourth IMO Greenhouse Gas Study (2020) [3]; (4) The Sixth Assessment Report (2022) [6]; and (5) The Paris Agreement [7]. Within the stated context, aligning with the International Maritime Organization’s (IMO) Initial Strategy on the Reduction of Greenhouse Gas Emissions from Ships, the Clydebank Declaration, launched at the COP26 summit in Glasgow in November 2021, serves as a foundational framework for establishing green shipping corridors [8].

According to the Global Maritime Forum (GMF), a green shipping corridor (GSC) is defined as “a shipping route between two major port hubs (including intermediary stopovers) on which public and private initiatives catalyze the technological, economic, and regulatory feasibility of operating zero-emission ships” (GMF, 2021) [9]. This definition has gained broad acceptance within the maritime sector, being adopted by various stakeholders, including C40 Cities and DN [10].

Green shipping corridors are currently in the initiation stage, the first of four implementation stages, where key stakeholders seek to establish a shared vision and identify suitable trade routes for zero-emission shipping [11]. Since green shipping corridors are complex, their success depends on the cooperation of all actors in the maritime value chain rather than a single stakeholder. Their implementation depends on fuel producers, logistics providers, port authorities, vessel operators, cargo owners, regulatory bodies, and investors, with each driving zero-emission shipping [12,13]. Key challenges include regulatory alignment, infrastructure upgrades, fuel costs, stakeholder coordination, technology standardization, and market uncertainty, all critical for their long-term viability [14,15].

A brief literature review on green shipping corridors indicates that the majority of scholars address the concept considering the aspects of (1) Stakeholder engagement and Governance; (2) Economic viability of Alternative fuels; and (3) Policy impacts and research agendas. Zhang and Feng (2024) develop a tripartite evolutionary game model integrating government, shipping enterprises, and shippers to analyze stakeholder responses and policy impacts accelerating zero-emission shipping corridors [16]. Jesus et al. (2024) propose a framework for green shipping corridors comparing alternative fuel cost-effectiveness to HFO [17]. Song et al. (2023) review developments in green shipping corridors initiated by the Clydebank Declaration at COP26, identifying stakeholder challenges and proposing research agendas for maritime decarbonization [18]. Ismail et al. (2024) propose a framework that addresses ports’ unique challenges in joining green shipping corridors by engaging diverse stakeholders to drive maritime decarbonization [19]. Bengue et al. (2024) propose a fuzzy AHP framework to prioritize criteria for establishing green maritime corridors, emphasizing environmental compatibility and economic viability for decarbonization [20].

To the authors’ knowledge, there is a scarcity of studies focusing on conducting a comprehensive overview that integrates policy frameworks, technological adaptations, and stakeholder collaboration within this emerging field. To bridge the identified gap, this paper conducts a bibliometric analysis to examine the evolution, impact, and research trends of green shipping corridors, focusing specifically on technology adaptations, stakeholder collaboration mechanisms, and policy frameworks. The main four objectives of this paper are as follows: (1) analyze the evolution of scholarly output within the GSC research domain; (2) identify influential articles, journals, authors, institutions, and countries using citation analysis metrics; (3) distinguish and analyze underlying research clusters through bibliographic coupling; and (4) synthesize insights related to policy, technology, and stakeholder collaboration.

This paper is structured as follows. Section 2 contains the bibliometric analysis research methodology regarding data collection, analytical tools, and the application of Boolean search term operators. Section 3 outlines the bibliometric analysis findings, presenting the foundational results of the methodology. Section 4 presents the main findings and research insights from research clusters. Section 5 synthesizes overarching insights on policy, technology, and stakeholder collaboration for sustainable maritime transport. Section 6 concludes with key findings.

2. Bibliometric Analysis Research Methodology

This section outlines the methodological framework employed for the bibliometric analysis, structured into a systematic, five-step approach. It begins by clearly defining the scope and parameters of the literature search. Next, it details the selection criteria used to identify relevant scholarly publications. Following this, the data extraction techniques utilized to capture and organize bibliographic data are described. Finally, the section addresses the analytical methods, including citation metrics and visualization techniques, used to identify key patterns and research clusters, thus facilitating a comprehensive exploration of contemporary scholarship on green shipping corridors.

2.1. Bibliometric Analysis Methodological Process: A Five-Step Approach

Bibliometric analysis is a widely recognized method in library and information science that employs statistical techniques to systematically evaluate scholarly literature, integrating both quantitative and qualitative dimensions [21]. By examining citation networks, this approach pinpoints central authors, influential publications, leading journals, and foremost research institutions. Moreover, it uncovers thematic clusters, dominant research trends, and emerging topics across academic disciplines, thereby providing researchers with an impartial framework for identifying foundational works and tracking significant developments within their fields [22].

Authors [23] have highlighted the distinct strengths of bibliometric analysis, notably its ability to quantitatively chart scholarly research areas. This approach systematically organizes extensive bodies of academic literature, facilitating the creation and appraisal of evolving knowledge structures. The scholars recommend supplementing methods with qualitative techniques, such as content analysis, to interpret unstructured data, including texts, images, and symbols. This ensures methodological rigor, reproducibility, and transparency regarding bibliometric studies yielding reliable and unbiased results. As a result, these methodologies substantially improve literature reviews by offering systematic and replicable evaluations that produce robust and trustworthy insights [24]. This lays the foundations for developing a five-step approach for implementing the bibliometric analysis research methodology regarding the green shipping corridors research domain, as presented in Figure 1.

The diagram depicts the five-step bibliometric analysis approach utilized to map and analyze the green shipping corridors research domain. The five steps are briefly discussed as follows:

• Step 1. Data Collection through ISI Web of Science Search:

A comprehensive search was conducted in the ISI Web of Science (WoS) database, incorporating relevant keywords, Boolean operators, and search filters. A total of 238 articles were identified, forming the final dataset, as presented in

Table 1. ISI WoS search findings on green shipping corridors.

Step	Keyword Search	No. Articles
1	“Green Shipping Corridor*”	21
2	(“Green Shipping Corridor*” OR “Zero-Emission Shipping”)	46
3	(“Green Shipping Corridor*” OR “Zero-Emission Shipping” OR “Sustainable Maritime Transport”)	76
4	(“Green Shipping Corridor*” OR “Zero-Emission Shipping” OR “Sustainable Maritime Transport” OR “Sustainable Shipping”)	228
5	(“Green Shipping Corridor*” OR “Zero-Emission Shipping” OR “Sustainable Maritime Transport” OR “Sustainable Shipping” OR “Maritime Decarbonization”)	269
6	(“Green Shipping Corridor*” OR “Zero-Emission Shipping” OR “Sustainable Maritime Transport” OR “Sustainable Shipping” OR “Maritime Decarbonization” OR “Green Shipping*”)	528
7	(“Green Shipping Corridor*” OR “Zero-Emission Shipping” OR “Sustainable Maritime Transport” OR “Sustainable Shipping” OR “Maritime Decarbonization” OR “Green Shipping*” OR “Low-Carbon Shipping*”)	598
8	(“Green Shipping Corridor*” OR “Zero-Emission Shipping” OR “Sustainable Maritime Transport” OR “Sustainable Shipping” OR “Maritime Decarbonization” OR “Green Shipping*” OR “Low-Carbon Shipping*”) AND “Maritime”	455
9	Exclusion Criteria: English Language	454
10	Exclusion Criteria: Article	388
11	Exclusion Criteria: Article Manual Screening for Inquired Relevance	238

.

• Step 2. Bibliometric Analysis and Network Construction:

Two bibliometric software packages were employed, VOSviewer and the bibliometrix package in R. The selected 238 articles were analyzed in VOSviewer to construct a network of interconnected document clusters, as stated in Appendix A. VOSviewer is a specialized software developed for the construction and visualization of bibliometric maps [25]. VOSviewer is easy to operate, offering numerous visualization options—co-citation, bibliographic coupling, co-word, and co-author network analyses—and supports combining data from multiple databases (ISI WoS and Scopus). In contrast, other bibliometric software options, such as CiteSpace’s data preparation, can be confusing, and its clustering may fail in emerging fields, while Gephi (version 0.10) requires pre-processing data using Bibexcel or Excel [26]. The bibliographic coupling methodology applied to 15 citation links per document resulted in a total of 115 articles in the network. The bibliometrix package in R revealed the foundational insights regarding the green shipping corridors research domain, located in Section three of the article.

• Step 3. Thematic Clustering:

The employment of bibliographic coupling revealed a threshold of 15 shared references per article. This approach enabled the distinguishing of four thematic clusters, each with its own subclusters, collectively encompassing 115 articles from the original dataset.

• Step 4. Selection of the Most Influential Articles in the Clusters:

Articles within each of the four clusters were assessed according to two key VOSviewer metrics, (1) Total Link Strength, reflecting the extent of an article’s connectivity within the citation network, and (2) Total Citations, measuring the recognized impact within the dataset. A weighted mean average of these metrics was used to pinpoint the most significant contributions within each cluster. Five articles per cluster were selected, resulting in a refined sample of twenty articles. Focusing on highly cited and strongly networked papers ensured that the subsequent content analysis focused on the field’s foundational and most influential scholarship.

• Step 5. Synthesis of Findings:

The final step of the bibliometric analysis synthesized the gaps and trends from the clusters and their respective subclusters, providing a basis for further scholarly investigation and industry recommendations.

The five-step methodology systematically examined research patterns related to green shipping corridors, specifically emphasizing policy adoption, technology integration, and stakeholder collaboration, thereby providing a structured foundation for future scholarly exploration and strategic industry practices.

2.2. Bibliographic Data Extraction Process

The fundamental aspect of bibliometric analysis constitutes the accumulation of bibliographic datasets from various scientific databases. The bibliometric dataset for this study, spanning the past 23 years, was compiled on 3 February 2025 using the ISI Web of Science, a highly esteemed scientific database in the academic community. Table 1 presents a detailed 11-step keyword search process, employing Boolean search terms.

Step 1 started with the keyword “Green Shipping Corridor”, which retrieved 21 articles. Step 2 expanded the scope slightly by adding “Zero-Emission Shipping”, increasing the results to 41 articles. In Step 3, including “Sustainable Maritime Transport” accumulated the number to 76 articles, indicating that sustainability-related terms are more prevalent in the literature. Step 4 added more Boolean operators (ORs) and multiple sustainability-related terms, leading to 228 articles, showing a notable increase. By Step 5, adding “Maritime Decarbonization” yielded 269 articles, suggesting growing academic interest in decarbonization topics. Step 6 introduced “Green Shipping”, which significantly increased the count to 528 articles, highlighting that “Green Shipping” is a widely covered topic. Step 7 added “Low-Carbon Shipping”, raising the total to 598 articles, the highest at this point, reflecting the extensive literature on low-carbon initiatives in maritime contexts. In Step 8, applying the AND operator with “Maritime” reduced the results to 455 articles, indicating a more targeted search within maritime-related studies. Step 9 excluded non-English language articles, reducing the dataset to 454 articles, showing minimal non-English content, which implies the prevalence of English in the maritime sustainability literature. Step 10 limited the results to articles only (excluding conference papers, reviews, etc.), narrowing it further to 388 articles, focusing on peer-reviewed sources. Step 11 involved manual screening for relevance results in 238 articles, ensuring that only highly relevant studies were included in the final analysis.

A careful and detailed examination of the latest edition of the “Getting to Zero Coalition Annual Progress Report on Green Shipping Corridors 2024” resulted in the selection of key phrases such as “Green Shipping Corridors”, “Zero-emission shipping”, “Sustainable Maritime Transport”, “Sustainable Shipping”, “Maritime decarbonisation”, and “Low-carbon Shipping”, which were then used as criteria for the manual filtering of articles [11]. Studies that were excluded related to the following: (1) Algorithm and Model Comparison; (2) Simulation and Computational Modeling; (3) Experimental and Empirical Investigations; and (4) Noise Review Analyses [27,28,29,30].

3. Bibliometric Analysis: Findings and Research Insights

This section presents a comprehensive bibliometric analysis of the research domain on green shipping corridors, examining key trends, collaborative patterns, and influential contributions in the field. It provides an overview of the main information in the dataset (Section 3.1), annual scholarly output (Section 3.2), rankings of publication outlets (Section 3.3) and individual publications (Section 3.4), top scholars (Section 3.5), institutional contributions (Section 3.6), country-level productivity (Section 3.7), and a visual three-fields plot illustrating interactions among authors, keywords, and countries (Section 3.8).

3.1. Bibliometric Overview of Green Shipping Corridors

3.1.1. Dataset Main Information

This bibliometric dataset spans the period from 2002 to 2025, covering 238 documents derived from 93 sources (journals, books, and other outlets). The annual growth rate of these publications stands at 12.16%, reflecting a steady increase in scholarly output over time. In terms of temporal characteristics, the documents’ average age is 4.09 years. Each document garners a mean of 23.08 citations, with the entire dataset collectively citing 11,357 references.

3.1.2. Document Contents

The dataset contains 565 Keywords Plus (ID) and 866 distinct Author’s Keywords (DE). These sets of keywords offer insight into the major thematic areas and conceptual approaches within the field of green shipping corridors.

3.1.3. Authors and Author Collaboration

A total of 654 authors contributed to this body of work, with 24 authors producing single-authored documents. Across the dataset, 27 documents are single-authored, contrasting with multi-authored papers, which have an average of 3.68 co-authors per document. International collaboration is notably high, accounting for 38.24% of all co-authorships, underscoring significant global engagement and cross-border research efforts within green shipping corridor studies.

3.1.4. Document Types

Among the collected publications, 230 are categorized as journal articles. Additionally, there is a small array of hybrid designations, including (1) one item listed as both an article and book chapter; (2) three as an article and early access; and (3) four as an article and proceedings paper. This distribution underscores the varied channels of scholarly communication within the field.

3.2. Annual Scholarly Output

The annual publication counts provide insights into the evolution of research on green shipping corridors. The annual publication counts are depicted in Figure 2.

Figure 2 reveals that the earliest recorded scholarly contribution to green shipping corridors appeared in 2002, represented by a single publication. Over the following decade from 2003 to 2012, the output remained minimal or nonexistent, featuring only sporadic entries (particularly in 2010 and 2011). Beginning in 2013, however, the domain underwent a discernible increase, rising from three articles in 2013 to four in 2014. A marked surge followed in 2015, with 10 publications, suggesting growing academic engagement.

Despite a slight decline to 5 publications in 2016, the broader trend remained upward, as the number of publications more than doubled by 2018 (reaching 14) and subsequently climbed to 20 in 2019 and 29 by 2021. The highest output recorded in the dataset was observed in 2024, with 42 publications. By 2025, the count stands at 14 publications. However, this figure may reflect partial reporting due to ongoing studies or pending publications. Overall, these findings underscore a robust and accelerating trajectory of scholarly attention toward green shipping corridors, particularly since the mid-2010s.

3.3. Ranking of Publication Outlets by Bibliographic Indices

The most prominent publication outlets contributing to research on green shipping corridors are presented in

Table 2. Publication outlet rankings by bibliographic indices.

No	Publication Outlet	NA *	LC *	LC/NA *	h-Index	PY Start *
1	Sustainability	20	200	10.0	8	2018
2	Transportation Research Part D	16	617	38.6	12	2014
3	Journal of Marine Science and Engineering	13	154	11.8	6	2019
4	Maritime Policy & Management	11	307	27.9	8	2014
5	Journal of Cleaner Production	10	431	43.1	8	2015
6	Transportation Research Part E	10	310	31.0	7	2015
7	Ocean & Coastal Management	9	116	12.9	5	2002
8	Marine Policy	8	183	22.9	4	2017
9	International Journal on Hydrogen Energy	7	227	32.4	4	2021
10	Ocean Engineering	7	242	34.6	6	2015

* NA (Number of Articles); LC (Local Citations); LC/NA (Local Citation-to-Number of Articles Ratio); PY Start (Publication Year Start).

. Key bibliometric indicators, such as the number of articles, local citations, local citation to number of articles ratio, h-index, and starting publication year underscore each publication outlet’s impact and thematic relevance. This information offers valuable insights into how scholarly interest and publishing trends surrounding green shipping corridors have evolved across different journals over time.

Sustainability is the leading journal for the total number of publications (20), followed by Transportation Research Part D (16) and Journal of Marine Science and Engineering (13). Transportation Research Part D also tops local citations with 617, reflecting its prominence in the field. Journal of Cleaner Production has the highest local-citation-to-article ratio (43.1), underscoring its strong impact within the dataset. The highest h-index (12) belongs to Transportation Research Part D, indicating both a high citation volume and consistent influence across multiple papers. Ocean & Coastal Management is the earliest journal in the dataset (2002), highlighting an enduring interest in maritime environmental issues. Overall, these outlets serve as critical platforms for disseminating scholarship on green shipping corridors, with strong thematic emphases on sustainability, transport, and maritime engineering.

3.4. Ranking of Publications by Bibliographic Indices

This subsection presents the most highly cited publications in green shipping corridor research, offering insights into each work’s citation impact both within the present dataset (local citations) and in the broader scholarly literature (global citations). The publication rankings by citation impacts are presented in

Table 3. Publication rankings by citations.

No	Publication	Year	LC *	GC *	LC/GC *
1	Xing, H. (2021), J. Clean. Prod. [31]	2021	16	208	7.6
2	Lirn, T.C., (2014), Marit. Policy Manag. [32]	2014	10	54	18.5
3	Lun, Y.H.V., (2014), Marit. Policy Manag. [33]	2014	7	38	18.4
4	Parviainen, (T., 2018), WMU. J. Marit. Aff. [34]	2018	7	38	18.4
5	Iannaccone, (T., 2020), J. Clean. Prod. [35]	2020	6	100	6.0
6	Lister, J., (2015), Glob. Policy [36]	2015	5	36	13.8
7	Psaraftis, H.N., (2019), Marit. Econ. Logist. [37]	2019	5	54	9.2
8	Pierre, C., (2019), Int. J. Prod. Econ. [38]	2019	5	84	5.9
9	Lin, D.Y., (2021), J. Clean. Prod. [39]	2021	4	47	8.5
10	Alexandrou, S.E., (2022), Marit. Policy Manag. [40]	2022	4	25	16.0

* LC (Local Citations); GC (Global Citations); LC/GC (Local Citation-to-Global Citation Ratio).

.

Xing et al. (2021 [31], Journal of Cleaner Production) stands out with 16 local citations and 208 global citations, making it the most cited publication both within this dataset and in broader citation databases. Lirn et al. (2014 [32], Maritime Policy & Management) exhibits the highest LC/GC ratio (18.5%), indicating a particularly strong outreach within this corpus relative to its wider scholarly impact. Lun et al. (2014) [33] and Parviainen et al. (2018) [34] follow closely (both at 18.4%), underscoring their notable local influence. Meanwhile, Iannaccone et al. (2020 [35], Journal of Cleaner Production) achieves 6 local citations alongside 100 global citations, signaling broader recognition in sustainability research. Lister et al. (2015 [36], Global Policy) and Psaraftis et al. (2019 [37], Maritime Economics & Logistics) each accumulate five local citations, reflecting consistent engagement with green shipping corridor scholarship. Publications in this ranking span from 2014 to 2022 and appear across diverse journals—such as Maritime Policy & Management, Journal of Cleaner Production, and Global Policy—highlighting the interdisciplinary scope and continued evolution of the field.

3.5. Ranking of Scholars by Bibliographic Indices

The green shipping corridors research domain is shaped by a group of highly active and influential researchers, many of whom have made considerable contributions to sustainability and maritime studies. The data presented in

Table 4. Scholar rankings by bibliographic indices.

No	Scholar	NP *	TC *	TC/NP *	h_Index	PY Start *
1	Yuen K.F.	10	400	40.0	9	2017
2	Li K.X.	7	271	38.7	7	2018
3	Wang H.	9	130	14.4	7	2019
4	Wang X.	9	306	34.0	7	2017
5	Lun Y.H.V.	6	252	42.0	6	2011
6	Wang S.	12	299	24.9	6	2020
7	Acciaro M.	6	214	35.7	5	2014
8	Hansson J.	5	255	51.0	5	2020
9	Cheng T.C.E.	5	246	49.2	5	2011
10	Wong Y.D.	5	261	52.2	5	2017

* NP (Number of Publications); TC (Total Citations); TC/NP (Total Citation-to-Number of Publications Ratio); PY Start (Publication Year Start).

highlight the top contributors in terms of publication volume, citation impact, and the chronological onset of their research efforts.

Wang S has the highest number of publications (12), indicating significant engagement in green shipping corridors research. Yuen KF leads in total citations (400), reflecting a noteworthy overall impact in the field. Wong YD shows the highest average citations per publication (52.2), followed closely by Hansson J (51.0) and Cheng TCE (49.2). These figures highlight the substantial impact that each paper has achieved. Yuen KF and Wang H share an h-index of nine and seven, respectively, indicating a high level of consistently influential work. Several others (e.g., Wang X, Li KX) have a score of seven. Lun YHV began publishing in 2011, suggesting earlier involvement in the area. Others, such as Wang S (2020) [41] and Hansson J (2020) [42], represent more recent but rapidly influential entrants, underscoring the field’s growth in recent years.

3.6. Institutional Contributions in Publication Volume

The green shipping corridor research domain has garnered significant international attention, as evidenced by the breadth of institutional affiliations among active researchers.

Table 5. Institutional rankings by publication volume.

No	Institution	Publication Volume
1	Hong Kong Polytechnic University	50
2	Shanghai Maritime University	32
3	Nanyang Technological University	30
4	Dalian Maritime University	23
5	Chalmers University of Technology	21
6	Shanghai University	17
7	Wuhan University of Technology	17
8	Chung—Ang University	15
9	Kedge Business School	12
10	Shanghai Jiao Tong University	11

provides enumerations of the top ten institutions by publication volume, highlighting the global distribution of scholarship in this domain.

Hong Kong Polytechnic University leads with the highest publication count (50). Shanghai Maritime University (32), Dalian Maritime University (23), Shanghai University (17), Wuhan University of Technology (17), and Shanghai Jiao Tong University (11) collectively suggest a significant concentration of expertise and research activity in China (100 total publications). Nanyang Technological University in Singapore (30) and Chung-Ang University in South Korea (15) also feature prominently, reflecting the broader Asian engagement in green shipping corridors research (45 total publications). Chalmers University of Technology (Sweden, 21) and KEDGE Business School (France, 12) indicate meaningful contributions from European academia (33 total publications).

3.7. Ranking of Countries by Bibliographic Indices

Green shipping corridor research exhibits distinct international patterns, with several leading countries driving scholarly output and collaboration. The following data in

Table 6. Country rankings by bibliographic indices.

No	Country	PV *	APC *	SCP *	MCP *	MCP_Ratio *
1	China	79	20.6	56	23	0.29
2	Sweden	16	33.7	13	3	0.19
3	Norway	16	24.1	11	5	0.31
4	Germany	12	17.3	9	3	0.25
5	Finland	8	10.3	6	2	0.25
6	United Kingdom	9	24.4	5	4	0.44
7	Canada	7	50.3	5	2	0.29
8	Poland	6	16	4	2	0.33
9	Italy	5	31.2	4	1	0.20
10	Korea	10	18.2	3	7	0.70

* PV (Publication Volume); APC (Average Publication Citations); SCP (Single-Country Publications); MCP (Multi-Country Publications); MCP_Ratio (Multi-Country Publications Ratio).

present how each country’s contribution, average citation impact, and proportion of multi-country co-authorship shape the global landscape of maritime sustainability research.

China showcases the largest volume of publications in the green shipping corridor domain with 79 publications, though its average citations per article (20.6) are moderate in comparison to certain other countries. Canada (50.3) and Sweden (33.7) achieve the highest average citation counts per article, suggesting a strong impact relative to their total output. Korea has the highest MCP_Ratio (0.70), indicating that 70% of its publications involve authors from multiple countries. By contrast, Sweden, despite a high citation impact, registers a lower MCP_Ratio of 0.18. Several European countries (Sweden, Norway, Germany, Finland, the United Kingdom, Poland, and Italy) appear on the list, reflecting a robust regional engagement. The United Kingdom’s MCP_Ratio of 0.44 points to significant cross-border collaborations. Italy’s average of 31.2 citations per article reveals strong scholarly activity for its smaller output (five publications).

3.8. Three-Fields Plot Diagram

The three-fields plot diagram can be rendered as a Sankey diagram, offering a visual representation of quantitative flows and their interrelationships. These diagrams employ directed, weighted graphs whose weight functions adhere to flow conservation, ensuring that, for each node, the sum of incoming weights equals the sum of outgoing weights [25]. Depicted in Figure 3 is a Sankey diagram illustrating scholarly activity in the green shipping corridor domain, highlighting interactions among the most influential scholars (left), the principal keywords (center), and the contributing countries (right).

The diagram highlights several frequently appearing authors (Wang J, Acciaro M, Lun YHV, Zhen L, Bai KH, Yuen KF, Wang XQ, and Wong YD), reflecting their significant contributions or influence in the domain. Core themes include green shipping, sustainable shipping, decarbonization, maritime decarbonization, shipping, alternative fuels, hydrogen, sustainability, and maritime transportation. Prominent countries (e.g., China, Sweden, Singapore, Korea, the United Kingdom, Belgium, Norway, Germany, and Finland) emerge as major research bases regarding green shipping corridor research.

4. Research Clusters: Content Analysis

The comprehensive search within the ISI Web of Science database identified an initial set of 238 articles pertaining to the green shipping corridors research domain. In order to narrow the scope to highly interconnected and influential works, a minimum threshold of 15 bibliographic coupling citations per document was applied in the VOSviewer software, reducing the dataset to 115 articles. The bibliographic coupling analysis is a bibliometrics technique that connects documents citing the same reference, thereby facilitating the creation of document clusters [43]. This indicates a likelihood that the linked documents address a related subject matter, that is, a research cluster. A graphical representation of the 115-article dataset regarding cluster formation is presented in Appendix A.

Subsequently, an equal-weighted average approach—incorporating both total link strength and citation count—was employed to assess each publication’s relative impact and interconnectedness. This combined metric facilitated the selection of the top 20 articles deemed the most significant for further in-depth content analysis. These articles were then organized into four distinct clusters, each comprising five publications, as presented in

Table 7. Selected articles for content analysis allocated to respective research cluster.

Cluster 1: Sustainable Green Shipping Practices and Research	Cluster 2: Alternative Fuels and Low-Carbon Strategies for Maritime Transport	Cluster 3: Green and Low-Carbon Maritime Development	Cluster 4: Environmental Sustainability in Maritime Shipping
Yuen (2017) [44]	Xing (2021) [31]	Wang (2023a) [41]	Lister (2015a) [45]
Lai (2011) [46]	Hansson (2020) [42]	Yan (2020) [47]	Acciaro (2014a) [48]
Yuen (2018) [49]	Nguyen (2023) [50]	Christodoulou (2021) [51]	Baldi and Gabrielii (2015b) [52]
Yuen (2019a) [53]	Iannaccone (2020) [35]	Carriou (2019) [38]	Acciaro (2014b) [54]
Shi (2018a) [55]	McKinlay (2021) [56]	Chen (2019) [57]	Baldi (2018) [58]

.

Table 7 assigns the selected articles to four thematic clusters, each representing a distinct dimension of green shipping corridor research, as follows:

• Cluster 1: Sustainable Green Shipping Practices and Research; focuses on conceptual frameworks, performance metrics, and resource management in maritime operations.
• Cluster 2: Alternative Fuels and Low-Carbon Strategies for Maritime Transport; addresses comparative evaluations of fuel types and decision-based strategies for decarbonization.
• Cluster 3: Green and Low-Carbon Maritime Development; underscores policy perspectives, global industry trends, and advanced modeling for emission reduction.
• Cluster 4: Environmental Sustainability in Maritime Shipping; investigates governance mechanisms, financial decision making, and technological feasibility for greener maritime operations.

Figure 4 provides a visual depiction of the clusters and respective subclusters, illustrating their interconnections and core themes.

Due to the complexity of the green shipping corridor research domain, each of these four clusters also encompasses multiple subclusters, which will be discussed in detail in the subsequent sections of this paper.

4.1. Cluster 1: Sustainable Green Shipping Practices and Research

This main cluster encapsulates the broad domain in which each article situates itself, the (1) exploration, implementation, and impacts of environmentally sustainable practices in the shipping industry, as well as the (2) evolution of research within this domain. A detailed content analysis of the selected five articles results in the identification of three interconnected subclusters.

4.1.1. Subcluster 1: Conceptualization and Theoretical Integration

The first subcluster is identified as conceptualization and theoretical integration in the green shipping corridors research domain. Two articles focus on establishing a conceptual foundation and integrating relevant theories to explain sustainable practices. These works outline the antecedents and frameworks that guide sustainable or green shipping initiatives.

Yuen et al. (2017) employ a Structural Equation Model to stakeholder theory, planned behavior theory, and resource dependence theory in order to examine sustainable shipping practices via survey data from 186 shipping companies [44]. The structural model confirms that stakeholder pressure, attitude, and behavioral control significantly drive the adoption of sustainable practices, directly and indirectly enhancing business performance. All hypothesized relationships (H1–H7) are positive and statistically significant at a 95% confidence level. The following hypotheses are: (1) H1. Stakeholder pressure has a positive effect on sustainable shipping practices; (2) H2. Sustainable shipping practices have a positive effect on shipping companies’ business performance; (3) H3. Shipping companies’ attitude towards sustainability has a positive effect on sustainable shipping practices; (4) H4. Shipping companies’ perceived behavioral control of sustainability has a positive effect on sustainable shipping practices; (5) H5. Stakeholder pressure has a positive effect on shipping companies’ attitude towards sustainability; (6) H6. Stakeholder pressure has a positive effect on shipping companies’ perceived behavioral control of sustainability; and (7) Stakeholder pressure has a positive effect on shipping companies’ business performance. By examining drivers, practices, and performance in a triadic framework, the study demonstrates that stakeholder pressure influences business performance both directly and indirectly through its effects on shipping companies’ attitudes and behavioral control. Additionally, (1) bulk shipping companies experience greater stakeholder pressure compared to container shipping companies and (2) larger firms are more proactive in adopting these practices.

Lai et al. (2011) highlight increasing stakeholder awareness of environmental impacts from cargo movement, noting that shipping activities contribute to pollution, waste, and resource depletion [46]. The scholars outline the following six dimensions of green shipping practices (GSPs): (1) Company Policy and Procedure, (2) Shipping Documentation, (3) Shipping Equipment, (4) Shipper Cooperation, (5) Shipping Materials, and (6) Shipping Design and Compliance. Effective GSP adoption requires strong corporate commitment, cross-functional integration, and technological innovations, such as eco-friendly equipment and optimized voyage planning. Furthermore, institutional theory, which incorporates coercive, mimetic, and normative pressures, better explains GSP adoption than stakeholder theory. Enforced environmental regulations, industry norms, and customer demands drive firms toward the dual benefits of improved environmental performance and enhanced productivity.

Key considerations in this subcluster include considering how institutional theory and behavioral models inform sustainable practices and the processes involved in conceptualizing and adopting green shipping practices.

4.1.2. Subcluster 2: Performance, Outcomes, and Resource Management

The second subcluster considers performance, outcomes, and resource management in the green shipping corridors research domain. Two articles consider the evaluation of the effects of sustainable shipping practices on organizational outcomes, including (1) Customer loyalty, (2) Resource utilization, and (3) Overall business performance.

Yuen et al. (2018) examine how sustainable shipping practices (SSPs) influence shippers’ loyalty through perceived value, trust, and transaction cost [49]. Survey data from 289 shippers—further validated with 2433 shippers in Singapore—support a theoretical model integrating perceived value, social exchange, and transaction cost theories. The findings reveal that SSPs significantly boost perceived value (β = 0.54), which, in turn, enhances trust and reduces transaction costs, ultimately increasing loyalty. A comparison of alternative models indicates that the effect of SSPs on loyalty is fully mediated by these factors. The model explains approximately 50% of the variance in loyalty, emphasizing that sustainability initiatives must deliver tangible (1) economic, (2) quality, (3) emotional, and (4) social benefits to secure long-term shipper loyalty.

Yuen et al. (2019a) integrate the Resource-Based View (RBV), Relational View (RV), and Knowledge-Based View (KBV) to explain how sustainable shipping management can be enhanced through a systematic classification of organizational resources [53]. The scholars develop a comprehensive taxonomy that categorizes sustainability resources into the following three groups: intrafirm resources (e.g., supportive leadership, stakeholder focus, and training), interfirm relationship management resources (e.g., contractual and relational governance, and communication), and organizational learning resources (knowledge exploitation and exploration). Their empirical findings indicate that sustainable shipping management fully mediates the effects of these resource categories on overall business performance, demonstrating that the mere possession of resources is insufficient without their effective utilization and application. The analysis further reveals that intrafirm resources significantly contribute to the development of interfirm relationship management and organizational learning resources, indicating a mutually reinforcing and interdependent relationship among these resource types. From a managerial perspective, the study recommends that shipping companies strategically allocate their scarce production factors to first enhance intrafirm capabilities, then foster collaborative interfirm relationships, and finally promote organizational learning to achieve superior sustainability outcomes and improved business performance.

Key considerations in this subcluster include how performance metrics such as loyalty, trust, perceived value, and cost structures are influenced by a systematic classification of resources, as posited by the Resource-Based View, to inform business performance in sustainable shipping.

4.1.3. Subcluster 3: Methodological and Thematic Evolution

The third subcluster reveals the methodological and thematic evolution in green shipping corridor research. One article focuses on a meta-level examination of the field, addressing how research themes and methods have evolved over time in the context of green shipping.

Shi et al. (2018a) state that, over the past 30 years, environmental concerns related to maritime transportation have attracted significant attention from both academia and industry, prompting a steady evolution in green shipping research [55]. The authors conduct a comprehensive review of 213 papers published between 1988 and 2017 and reveal a marked increase in research activity since 2012, with 77.5% of the studies appearing during this recent period. Current research primarily focuses on addressing air pollution and has helped to clarify the classification of green shipping practices into distinct categories such as (1) Technical measures, (2) Operational options, (3) Market-based approaches, and (4) Recycling/reusing strategies. The research methods in green shipping are categorized into 11 groups, with mathematical and statistical analysis being the most prevalent at 39.57%, followed by economic modeling at 15.32%, case studies at 12.34%, and literature reviews at 9.36%. Additional methodologies, including bottom-up activity-based models (6.81%), scenario analysis (4.26%), surveys (2.98%), sensitivity analysis (2.98%), simulation (2.13%), bench testing (2.13%), and conceptual, content, and qualitative analysis (2.13%), complement the overall methodological mix. Before 2012, green shipping research primarily relied on basic methods such as case studies, literature reviews, and mathematical/statistical analyses, whereas post-2012 studies are increasingly adopting combined and multidisciplinary approaches. There is a notable deficiency in studies that quantitatively assess how green policy and standards affect the relationship between environmental and economic performance, and international collaborative research in this area remains scarce.

Key considerations in this subcluster include mapping the historical evolution and diversification of research themes in green shipping, as well as evaluating the changes in research design and analytical methods over time. This involves examining how research trends have developed over the years and identifying shifts in methodological approaches that have influenced the study of green shipping practices.

4.2. Cluster 2: Alternative Fuels and Low-Carbon Strategies for Maritime Transport

This main cluster encompasses the broad research domain, addressing how the maritime industry can transition toward lower carbon emissions. It includes both (1) strategic roadmaps for future fuel systems and (2) detailed evaluations of specific fuel technologies through quantitative and comparative methods. The detailed content analysis of the selected five articles results in the identification of two interconnected subclusters.

4.2.1. Subcluster 1: Strategic Pathways to Clean Fuel Strategies

This subcluster covers articles that adopt a forward-looking, strategic perspective on achieving low-carbon maritime transportation. It includes two works that articulate long-term pathways and identify comprehensive fuel-saving or clean fuel strategies. The emphasis is on mapping out transitions over time (e.g., toward 2050) and on understanding the systemic approaches required for a green maritime future.

Xing et al. (2021) conduct a comprehensive technological review to assess alternative marine fuels, aiming to achieve low-carbon maritime transportation by 2050 while simultaneously reducing the emissions of sulfur oxides, nitrogen oxides, and carbon dioxide [31]. Employing a multi-dimensional decision-making framework, the study qualitatively ranks various marine fuels and identifies zero carbon synthetic fuels—particularly hydrogen and ammonia—as vital for domestic and short-sea shipping, despite current cost and infrastructure challenges. The scholars conclude that ships require fuels with a high energy density—both by mass and by volume—to maximize the available space and weight capacity for payloads, making energy density a critical factor in fuel selection. Although hydrogen offers a high energy density by mass and dramatic CO₂ savings, its low volumetric energy density restricts its use on ships where reduced fuel storage capacity is not a critical issue, such as high-density cargo vessels, Ro-Pax, ferries, and short-sea shipping vessels. Ammonia emerges as a promising alternative because it is a carbon-free fuel that provides a more balanced compromise between mass and volumetric energy density, despite challenges related to the technical maturity of onboard equipment and upstream feedstock availability. Other marine fuels such as LNG, CNG, LPG, methanol, ethanol, biodiesel, and DME are considered as acceptable alternatives from an energy density perspective, as they maintain a sufficient energy output without significantly compromising vessel range or payload. To accommodate the distinct combustion characteristics of fuels like ammonia—which requires a secondary ignition fuel in internal combustion engines—and methanol, ship engines often necessitate significant modifications, including tailored ignition systems and optimized fuel injection mechanisms. Ultimately, the strategic evaluation of alternative marine fuels for achieving low-carbon maritime transportation prioritizes energy density alongside environmental benefits, ensuring that the selected fuels do not unduly limit the operational performance of ships while contributing to emission reductions.

Nguyen et al. (2023) state that achieving the goal of low-carbon shipping by 2050 necessitates a holistic approach that incorporates alternative fuels alongside various technological and operational initiatives [50]. The authors evaluate recent clean fuels and innovative technologies for vessels, categorizing alternative fuels into low-carbon, carbon-free, and carbon-neutral types based on their distinct properties. The article reviews comprehensive strategies for reducing CO₂ emissions from ships by evaluating a wide range of low-carbon fuels, clean renewable energy sources, and supportive regulatory frameworks, while emphasizing the role of intelligent energy management systems and battery storage in promoting energy savings. It highlights that robust operational and control practices—including advanced electricity control, energy conversion, and consumption monitoring—are essential for achieving effective energy efficiency, emissions mitigation, and cost savings in maritime operations. Biofuels, though commercially attractive when used in combination with other fuels, face significant challenges such as high production costs, feedstock limitations, and issues with cold flow, material compatibility, and fuel stability, with emerging research into novel feedstocks like algae and waste oil offering potential cost reductions. The review identifies hydrogen and ammonia as promising zero-carbon fuels for short-sea and domestic shipping due to their high energy density by mass, but notes that their adoption is currently limited by high production costs, specialized storage requirements, and transportation challenges, with ammonia also serving as a potential hydrogen storage medium.

The integration of these alternative fuels often requires the use of precise blending ratios—such as methanol fractions of 10%, 20%, or 85% in commercial methanol–gasoline and methanol–diesel blends—to ensure that performance and emission reduction targets are met without compromising engine reliability. Furthermore, transitioning to fuels like ammonia not only demands modifications in engine configurations—such as the integration of secondary ignition systems—but also necessitates a re-examination of fuel blend strategies to meet both performance and environmental criteria.

The successful transition to low-carbon maritime transportation depends on selecting the appropriate fuel and propulsion system combinations for different ship types and routes, with renewable methanol emerging as the most promising option for global shipping and LNG preferred for long-distance operations.

Key considerations in this subcluster include temporal and policy orientation by emphasis on long-term planning and policy implications, and a system-level perspective by providing an analysis of industry-wide transitions and comprehensive strategy formations.

4.2.2. Subcluster 2: Comparative and Decision-Based Evaluations of Alternative Fuels

This subcluster is centered on detailed, comparative evaluations of specific alternative fuels. Two studies employ advanced modeling techniques—such as energy systems modeling and multi-criteria decision analysis—to assess the performance, sustainability, and viability of various fuel options. One article is a comparative study, including technology assessments and scenario analyses as central themes.

Hansson et al. (2020) evaluate ammonia’s prospects as a future marine fuel by comparing it with other marine fuels through both energy systems modeling and a multi-criteria decision analysis (MCDA) framework [42]. The results indicate that no single fuel option excels across all considered performance measures, such as cost, emissions, and reliable supply. However, when taking stakeholder preferences, the following should be taken into consideration. Stakeholder groups such as ship owners, fuel producers, and engine manufacturers place a high emphasis on economic factors and fuel costs, resulting in LNG and natural-gas-based methanol being ranked at the top, while ammonia options tend to rank lower for these groups. In contrast, governmental authorities, prioritizing greenhouse gas emissions and regulatory compliance, rank renewable hydrogen in fuel cells highest and renewable ammonia in fuel cells next, whereas natural-gas-based ammonia remains at the bottom of their ranking. For the combined stakeholder group, LNG is ranked highest, followed by hydrotreated vegetable oil used in ICEs and renewable hydrogen in fuel cells, with renewable ammonia options ranking fifth (when used in fuel cells) and eighth (when used in ICEs) and natural-gas-based ammonia ranking lowest.

Iannaccone et al. (2020) develop a specific methodology to compare the safety and sustainability of alternative fuel systems for large cruise ships, providing essential guidance during the early design stages [35]. The methodology is employed in the following four respective schemes: (1) low-pressure dual-fuel (LNG-based); (2) high-pressure dual-fuel (LNG-based); (3) lean burn spark ignition (LNG-based); and (4) conventional marine fuel oil (MGO-based). The study demonstrates that LNG-based fuel systems markedly outperform conventional MGO systems in sustainability, with LNG alternatives achieving substantial environmental benefits and a lower overall sustainability impact. Among LNG-based options, the low-pressure dual-fuel system (Scheme 1) emerges as the most sustainable, delivering a 35% overall reduction in sustainability impact relative to MGO—primarily due to a 44% reduction in environmental impact and moderate cost reductions. In contrast, the high-pressure dual-fuel system (Scheme 2) is penalized by higher operating and maintenance costs, as well as a 62% increase in the inherent safety index compared to MGO, making it the least sustainable among the LNG alternatives.

McKinlay et al. (2021) adopt a bottom-up approach, directly comparing hydrogen, ammonia, and methanol for long-distance international shipping by calculating key technical requirements—including fuel storage volume and mass—and evaluating emissions, supply, safety, and storage aspects using real-world data [56]. The scholars find that hydrogen is the most promising candidate, as its production and supply chain can be decarbonized more easily than those of ammonia and methanol, which require energy-intensive processes such as the Haber–Bosch process. The production upscaling needed to meet global shipping demand is significantly lower for hydrogen (171%) compared to ammonia (391%) and methanol (859%), highlighting hydrogen’s superior feasibility. While methanol requires less mass and volume for onboard storage than ammonia and is easier to store than hydrogen, the study shows that the cryogenic storage of hydrogen is still viable, capable of powering a large vessel using the equivalent of 85 containers. Additionally, the research emphasizes that ships typically carry more fuel than is needed for a single voyage, and optimizing storage levels closer to actual usage can reduce mass and volume requirements, thereby making alternative fuels more viable.

Key considerations in this subcluster include methodological rigor in energy systems modeling and technology-specific insights regarding detailed analyses of individual fuel options to enable decision makers to weigh technical, environmental, and economic factors.

4.3. Cluster 3: Green and Low-Carbon Maritime Development

This main cluster encompasses research that explores pathways toward reduced emissions and sustainable practices in the maritime industry. It includes studies that offer (1) broad overviews of industry trends and policy opportunities, (2) detailed modeling and analytical approaches for emission reductions, and (3) investigations of decarbonization initiatives at the operational level. A detailed content analysis of the selected five articles results in the identification of two interconnected subclusters.

4.3.1. Subcluster 1: Strategic Overviews, Industry Trends, and Policy Perspectives

This subcluster is focused on addressing the macro-level dynamics of green maritime development. Two articles provide comprehensive overviews, explore industry-wide trends, and assess the relationship between industry evolution (e.g., fleet development) and environmental performance. One article considers the drivers behind voluntary and policy-led initiatives aimed at decarbonization.

Wang et al. (2023a) conduct a comprehensive literature review, drawing from databases such as Elsevier ScienceDirect, Scopus, Web of Science, and Google Scholar to assess the current research status and development trends in green shipping management and green port construction [41]. The findings indicate that green shipping management research is predominantly focused on addressing practical emission reduction challenges, while studies on green port construction largely employ mathematical optimization models to minimize costs or maximize profits. Government intervention is pivotal in this system, as policies like cap-and-trade regulations and targeted subsidies incentivize ports and ship operators to proactively reduce emissions and overcome potential barriers. Collaborative governance integrates operational strategies, such as optimized berth allocation, sailing speed, and coordinated scheduling, between ports and shipping companies to reduce emissions and enhance overall efficiency.

Christodoulou and Cullinane (2021) analyze how shipping firms, exemplified by the Swedish operator Stena Line, respond to environmental challenges through voluntary sustainability initiatives integrated within their corporate social responsibility (CSR) strategies and compliance efforts [51]. In response to fierce competition and high demand elasticity in the RoPax market, Stena Line focuses on service differentiation and strong customer relationships, ensuring high-capacity utilization and frequent departures to maintain its competitive edge. To advance its strategic vision for sustainable shipping, Stena Line has implemented a range of measures, including (1) the provision of onshore power supply (OPS) at ports and on vessels; (2) vessel conversion to methanol; (3) ferry electrification; (4) the construction of larger RoPax vessels; and (5) energy-saving programs centered on crew involvement and continuous training, while also analyzing the challenges and benefits of these initiatives to inform future policy and operational improvements. The scholars conclude that economic and technological barriers, particularly high initial installation costs, impede the widespread adoption of these initiatives, making national or regional economic incentives essential to promote further green development in the maritime sector.

Chen et al. (2019) utilize an allometric model based on biological scaling laws to establish a relationship between (1) fleet size and (2) GHG emissions, enabling future emissions forecasting [57]. The research compares indirect emission reductions from operational strategies, such as slowing navigation speed and putting ships into idle status, with the direct impacts of IMO standards (EEDI and EEOI). Positive allometry is identified regarding N₂O emissions because they have a scale index greater than one, indicating that they increase at a faster rate relative to the growth in fleet size. Negative allometry is identified regarding CO₂ and CH₄ emissions because they have scale indices below one, meaning that, as the global fleet grows, these emissions increase at a slower rate. The model’s predicted future emissions are then benchmarked against the GHG emission limits set by the IMO at its 72nd meeting. This comprehensive comparison validates the effectiveness of the allometric model as a predictive tool for assessing marine GHG emissions and guiding policy decisions. The paper calls for future research to refine the allometric model by incorporating factors such as (1) regional differences, (2) ship age, and (3) registration, and to adopt probabilistic approaches to better predict the contributions of various factors to future shipping GHG trends.

Key considerations within this subcluster include industry dynamics in terms of how trends in fleet development and operational practices influence overall emissions and the role of voluntary initiatives and policy frameworks in guiding decarbonization efforts.

4.3.2. Subcluster 2: Quantitative Modeling, Prediction, and Emission Reduction Analysis

This subcluster is dedicated to studies employing quantitative methods to (1) predict, (2) analyze, and (3) reduce emissions in maritime operations. Two articles in this group leverage modeling approaches, multi-trade analysis, and empirical evaluations to understand fuel consumption patterns and assess the effectiveness of emission reduction strategies.

Yan et al. (2020) develop a two-stage model for a dry bulk ship using a random forest regressor, leveraging ship noon reports combined with weather forecast data, to predict fuel consumption, followed by a speed optimization model that minimizes fuel use while ensuring timely arrival, offering a more interpretable and efficient solution compared to traditional ANN-based models [47]. Computational experiments using two 8-day voyage reports show that the proposed model can reduce fuel consumption by 2–7%, leading to significant reductions in CO₂ emissions. The analysis confirms that ship sailing speed is the dominant factor influencing fuel consumption, followed by total carried cargo, while combined wind, wave, and swell conditions also have a notable impact, and current type has minimal influence. By integrating machine learning with optimization, the model provides a pioneering, non-analytical approach to better understand and manage ship fuel consumption, enabling shipping companies to more precisely plan daily sailing speeds and improve overall energy efficiency.

Carriou et al. (2019) develop an empirical tool to assess the progress toward carbon-clean maritime supply chains [38]. The study’s multi-trade analysis of container shipping reveals that annual CO₂ emissions decreased by approximately 33% from 2007 to 2016. This 33% reduction is primarily driven by a 53% improvement in CO₂ fuel efficiency—resulting from a 35% decrease in commercial speed and a 34% benefit from increased vessel size—and a 21% reduction in the average distance traveled due to a new network design. These improvements are partially offset by an 81% increase in the deployed fleet capacity, which stems from a 6% rise in the number of vessels combined with a 71% increase in the average ship size. Trade-specific variations were observed for the Asia–North America route, where a 50% reduction in emission intensity was mostly due to a decreased commercial speed (−47%), whereas for Asia–South America trade, a 44% improvement was mainly attributed to increased vessel size.

Key considerations within this subcluster include an emphasis on advanced modeling techniques that offer detailed, data-driven insights and the evaluation of emission reduction strategies across different segments of maritime shipping to inform decision making and policy.

4.4. Cluster 4: Environmental Sustainability in Maritime Shipping

This main cluster encompasses research focused on advancing environmental sustainability within maritime shipping through both strategic governance and financial decision making, as well as through technological innovations and energy efficiency assessments. A detailed content analysis of the selected five articles results in the identification of two interconnected subclusters.

4.4.1. Subcluster 1: Governance and Financial Decision Making for Environmental Compliance

This subcluster gathers studies that examine the institutional, regulatory, and investment frameworks designed to achieve environmental compliance in maritime shipping. It includes two articles that use real options approaches to evaluate investment under uncertainty and one article exploring transnational environmental governance.

Acciaro (2014a) states that retrofitting vessels to use LNG requires significant upfront investment, and there is a high uncertainty regarding the price differential between LNG and conventional fuels, as well as the reliability and availability of LNG supply [48]. The critical decision for shipowners is whether to invest in LNG retrofitting immediately to benefit from lower fuel prices or to defer such investment until market uncertainties are resolved. The paper uses real options analysis (ROA) to evaluate LNG retrofitting investments, demonstrating that, while traditional discounted cash flow models might reject such investments, ROA reveals that deferring the decision can be a strategically valuable option. The model shows that deferral options are particularly beneficial when capital expenditure is high, as waiting allows shipowners to reduce risks by obtaining better insights into LNG price trends, technological advancements, and market developments.

Acciaro (2014b) states that advanced decision support tools, such as real options analysis, are essential to manage the increased complexity in managerial decision making due to evolving regulations [54]. The model presented in the paper demonstrates a trade-off between low LNG fuel prices and the high capital costs associated with retrofitting ships for LNG use, highlighting the strategic value of deferring the investment. In a case study on a Handymax vessel, the analysis indicates that, while an LNG retrofit is not economically justified under current conditions, it could become viable as early as 2015 if LNG–oil price differentials and capital costs become favorable. A comparison with exhaust gas cleaning systems (EGCSs) shows that, although EGCSs require lower capital expenditure, they do not enable shipowners to benefit from low LNG prices, thereby supporting the strategy of deferring LNG investments.

Lister et al. (2015a) stipulate that the shipping industry lags in environmental protection due to low public visibility of its impacts and misaligned industry and consumer interests, compounded by the limited and challenging orchestration efforts of the IMO [45]. The scholars develop the concept of “orchestration” as the use of both direct and indirect regulatory tools, as well as a mix of hard and soft power, to address global environmental challenges. Furthermore, the concept focuses on the following four key dimensions: (1) issue visibility, (2) interest alignment, (3) the scope of environmental issues, and (4) regulatory fragmentation and uncertainty, which all affect the effectiveness of environmental governance. The analysis reveals the challenges and opportunities for the IMO to lead and coordinate transnational efforts, suggesting that a more collaborative approach involving (1) non-state actors and (2) intermediaries is essential for advancing environmental progress in maritime shipping.

Key considerations within this subcluster include the role of transnational policies in shaping environmental compliance regarding institutional coordination and how real option methodologies provide insights into managing investment risk under regulatory and market uncertainty.

4.4.2. Subcluster 2: Technological Feasibility and Energy Efficiency Analysis

This subcluster comprises two articles that focus on the technological and operational aspects of achieving environmental sustainability through improved energy efficiency and waste heat recovery. It emphasizes quantitative performance analyses and feasibility studies that support the adoption of innovative technologies in maritime applications.

Baldi and Gabrielli (2015b) addresses the critical need for improved energy efficiency in shipping by analyzing the feasibility of installing waste heat recovery (WHR) systems on vessels [52]. It introduces a methodology that calculates the available energy and exergy for WHR systems, comparing these with the vessel’s propulsion and auxiliary power demands based on its operational profile. The proposed method serves as a decision support tool for shipowners by linking expected fuel savings to payback time and required capital investment. The case study results indicate that, depending on the waste heat sources and WHR system efficiency, realistic fuel savings of 5–15% can be achieved, highlighting both the environmental and economic benefits of such technologies.

Baldi et al. (2018) state that the complexity of a cruise ship’s energy system makes it a prime subject for energy and exergy analysis, as demonstrated by a one-year study of a Baltic Sea cruise ship [54]. The energy analysis revealed that propulsion consumes 46% of the ship’s total energy, while both heat and electric power generation each account for 27%. The exergy analysis identified that 76% of energy is lost through combustion processes, with further losses occurring in equipment like turbochargers, heat recovery steam generators, steam heaters, preheaters, sea water coolers, and electric generators, especially in engines without heat recovery devices. By combining direct onboard measurements with computational models, the systematic approach used in this study provides a realistic representation of a ship’s energy behavior and identifies key areas for further detailed analysis, which can support efforts to reduce the environmental impact of ship energy systems.

Key considerations within this subcluster include the evaluation of emerging technologies that can improve energy efficiency and performance metrics as robust tools for measuring system performance.

4.5. Cross-Cluster Methodological Convergence in Green Shipping Corridors Research

The observed cross-cluster commonality is evident when similar methodological approaches are applied across distinct subclusters to examine green shipping corridors [59]. Advanced quantitative modeling techniques are employed in Cluster 2’s Comparative and Decision-Based Evaluations [37,56] and Cluster 3’s Quantitative Modeling, Prediction, and Emission Reduction Analysis [57], demonstrating a consistent commitment to data-driven analysis in different research contexts. Decision support frameworks, such as real options analysis in Cluster 4 [25,54] and resource-based approaches in Cluster 1 [46], underscore a common focus on managing investment risk and optimizing resource allocation. The integrated evaluation of environmental performance—spanning strategic clean fuel strategies in Cluster 2, emission reduction metrics in Cluster 3, and energy efficiency assessments in Cluster 4 [33,47,58]—further supports the claim that similar analytical frameworks are used across clusters to assess sustainability outcomes in maritime operations.

Cross-cluster commonality emerges primarily through the consistent use of three methodological approaches. First, advanced quantitative modeling techniques—including energy systems modeling, multi-criteria decision analysis, and machine learning methods (e.g., random forest regression)—are applied across clusters to evaluate technical performance and emission reductions [56,57]. Second, decision support frameworks, such as real options analysis and resource-based methodologies, are utilized to assess investment risks and optimize resource allocation, providing strategic insights into sustainable shipping practices [25,42,54]. Third, integrated environmental performance evaluations are conducted using metrics like energy efficiency assessments, exergy analysis, and emission reduction measurements, thereby unifying technical and strategic analyses across the research on green shipping corridors [33,58].

5. Overview of Policy, Technology, and Stakeholder Collaboration

The four clusters and their respective subclusters identified via bibliometric analysis form the foundation for a comprehensive overview on green shipping corridors. Specifically, the gathered insights are synthesized to highlight critical interconnections and trends in policy, technology, and stakeholder collaboration, three pivotal areas shaping sustainable advancement in this emerging field.

5.1. Policy Overview

This policy overview integrates key recommendations from relevant and selected articles from the study to highlight the critical roles of coordinated government support, flexible governance structures, and strategic investment tools in advancing green shipping corridors for maritime decarbonization.

A comprehensive policy overview of the green shipping corridor concept should adhere to the integration of the foundational insights from institutional theory, stakeholder influence, and the strategic role of policy in maritime sustainability. Lai et al. (2011) emphasize that the adoption of green shipping practices (GSPs) hinges on robust institutional frameworks characterized by coercive regulatory mechanisms, industry standard compliance (normative pressures), and market-driven environmental expectations (mimetic pressures) [46]. Policies must, therefore, reinforce these dimensions, ensuring that shipping companies integrate eco-friendly equipment and voyage optimization into corporate procedures, documentation, and design compliance [40].

Yuen et al. (2017) reinforce this view by demonstrating how stakeholder pressures significantly influence shipping companies’ sustainable practices. The integration of stakeholder theory, planned behavior theory, and resource dependence theory reveals that institutional policies must go beyond regulatory enforcement and include mechanisms for encouraging proactive corporate behavior, especially among larger firms, and consider differential pressures experienced by shipping subsectors such as bulk and container shipping [49].

The broader policy implications for fostering green shipping corridors are elaborated by [55]. The scholars identify a deficiency in policy frameworks that quantitatively assess the impact of green initiatives on both environmental and economic performance. The authors note that policymakers should bridge this shortcoming through interdisciplinary collaboration via the implementation of combined methodological approaches such as mathematical modeling, scenario analyses, and sensitivity analyses to inform targeted interventions and assess the efficacy of environmental regulations.

Policies should adhere to technological roadmaps and emission targets established through international agreements, as detailed by [31,50]. Policy frameworks should complement the adoption of zero-carbon synthetic fuels such as hydrogen and ammonia. These fuels are recommended for achieving significant emission reductions by 2050. Policies must address infrastructural development, technological maturity, and the economic viability of fuel alternatives, focusing on energy density and the specific operational needs of diverse shipping routes and vessel types.

Furthermore, the role of voluntary corporate initiatives under strategic regulatory guidance is explored by [51]. Their study indicates that voluntary sustainability measures, although impactful, require complementary economic incentives and regulatory support to overcome initial investment barriers. This aligns with [41], who underline the necessity of government-led collaborative governance integrating operational practices such as optimized berth allocation, sailing speed adjustments, and coordinated scheduling between ports and shipping operators.

Lastly, refs. [48,54] highlight that policy frameworks must incorporate flexible decision-making tools like real options analysis (ROA) to navigate uncertainties associated with investing in emerging environmental technologies such as LNG retrofitting. Policies that encourage strategic investment deferrals can minimize financial risks and incentivize long-term commitment to green shipping technologies.

In conclusion, policy frameworks supporting green shipping corridors are to be integrative, incorporating institutional theory perspectives, stakeholder engagement, multidisciplinary methodologies, strategic incentives, and flexible investment decision tools. Such comprehensive approaches can provide a safer foundation regarding the effective transition toward sustainable maritime operations, significantly reducing environmental impacts and promoting industry-wide adherence to green shipping practices.

Table 8. Policy recommendations regarding GSC development within the imitation phase.

Policy Name	Policy Definition	Reference
Institutional Frameworks for GSP Adoption	Policy frameworks leveraging coercive regulatory measures, normative industry standards, and mimetic market-driven pressures to ensure the adoption of green shipping practices (GSPs), including eco-friendly equipment and voyage optimization.	Lai et al. (2011) [46]
Stakeholder-Driven Sustainability Policies	Policies designed to engage stakeholders, utilizing stakeholder theory, planned behavior theory, and resource dependence theory to encourage sustainable behavior in shipping firms through direct and indirect influences.	Yuen et al. (2017) [44]
Quantitative Policy Impact Assessments	Policies necessitating quantitative assessments of how green initiatives influence environmental and economic performance, employing interdisciplinary methodologies including mathematical modeling and scenario analyses.	Shi et al. (2018) [55]
Zero-Carbon Fuel Transition Policies	Policies promoting adoption of alternative marine fuels (especially hydrogen and ammonia) with incentives for infrastructure investments, technological maturity, and addressing economic feasibility to achieve emission reduction targets by 2050.	Xing et al. (2021) [31]; Nguyen et al. (2023) [50]
Voluntary Initiative Support Policies	Economic and regulatory policies designed to support and incentivize corporate voluntary sustainability measures (e.g., electrification and vessel retrofitting), overcoming initial investment barriers and promoting widespread adoption.	Christodoulou and Cullinane (2021) [51]
Collaborative Governance Policies	Policies that foster integrated operational cooperation between ports and shipping companies, including optimized berth allocation, adjusted sailing speeds, and coordinated scheduling for emission reductions.	Wang et al. (2023) [41]
Flexible Investment Decision Policies	Policies employing strategic decision support tools (e.g., real options analysis—ROA) to address financial and market uncertainties in investment decisions for sustainable technologies, encouraging timely and informed investment choices.	Acciaro (2014a, 2014b) [48,54]
Transnational Environmental Governance Policy	Policies enhancing international regulatory coordination through orchestration, balancing direct and indirect regulatory tools and soft and hard governance approaches involving state and non-state actors to address environmental governance challenges effectively.	Lister et al. (2015) [45]
Strategic Operational Emission Reduction Policy	Policies that emphasize strategic and operational initiatives, including slow steaming, idle status management, and operational speed optimization, alongside regulatory compliance frameworks to achieve measurable emission reductions.	Chen et al. (2019) [57]; Yan et al. (2020) [47]
Technological Innovation and Adoption Policies	Policies supporting investment in innovative energy-efficient technologies (e.g., waste heat recovery systems), employing detailed feasibility and economic performance analysis to encourage technology uptake and sustainability in maritime operations.	Baldi and Gabrielli (2015) [52]; Baldi et al. (2018) [58]

categorizes a list of policy recommendations regarding GSC development within the initiation phase.

In accordance with document [11], Europe hosts 21 green shipping corridor (GSC) initiatives, while Asia has 14. European GSCs are largely guided by a mix of public–private and government leadership, whereas Asian corridors see stronger industry (PA)/third-sector drivers. Combining these insights with Table 8’s policy recommendations suggests focusing on institutional frameworks and stakeholder-driven policies in Europe, where regulatory alignment and collaborative governance can flourish. In Asia, voluntary initiative support and flexible investment decisions can address diverse market conditions and encourage technology adoption. Both regions benefit from zero-carbon fuel transition policies, emphasizing hydrogen and ammonia, and from robust transnational environmental governance. Coordinated approaches will expedite uptake, ensuring both regions achieve sustainable maritime outcomes.

5.2. Technology Overview

This technology overview synthesizes key insights from relevant studies to highlight the pivotal role of innovative alternative fuel systems, advanced energy management technologies, and optimized operational practices in enabling zero-emission maritime transport.

A comprehensive technology overview for green shipping corridors (GSCs) emphasizes innovative alternative fuel systems, advanced energy management technologies, and operational optimization to realize zero-emission maritime transport effectively. Central to achieving the long-term decarbonization targets for maritime transportation, alternative marine fuels represent an important element. Authors [31] have noted zero-carbon synthetic fuels such as hydrogen and ammonia, noting their critical relevance, especially in domestic and short-sea shipping contexts. These fuels are identified for their reductions in sulfur oxides, nitrogen oxides, and carbon dioxide emissions. The study emphasizes energy density—both by mass and volume—as a decisive criterion for technology selection, balancing environmental advantages with operational practicality, especially regarding cargo and vessel-specific operational constraints.

Scholars [50] further support this view through a comprehensive evaluation of alternative fuels, categorizing them into low-carbon, carbon-free, and carbon-neutral groups. The authors imply the importance of integrating technological innovations such as intelligent energy management systems, optimized fuel storage solutions, and advanced operational controls to ensure effective emission reduction. Biofuels are recognized as commercially attractive in hybrid configurations; however, challenges such as production costs and feedstock availability constitute barriers. Hydrogen and ammonia stand out as promising options due to their high energy density by mass, despite current barriers related to production, storage infrastructure, and upstream availability.

From a comparative and decision-oriented perspective, ref. [42] employ multi-criteria decision analysis (MCDA) frameworks to critically assess the viability of alternative fuels, underscoring that no singular option meets all operational and economic criteria perfectly. While LNG and methanol-based fuels currently hold higher commercial attractiveness due to their cost efficiency, renewable hydrogen and ammonia exhibit substantial environmental benefits, particularly favored by regulatory authorities emphasizing stringent emission controls. Authors [56] have further highlighted hydrogen’s potential for international shipping, emphasizing its superior feasibility due to comparatively lower production scaling requirements, despite technological challenges related to storage. The study illustrates that cryogenic hydrogen storage, despite volumetric limitations, remains viable for larger vessels through strategic storage optimization.

Beyond fuel selection, technological innovations enhancing energy efficiency are pivotal. Scholars [52] have explored the adoption of waste heat recovery (WHR) systems, demonstrating their potential to achieve fuel savings ranging from 5% to 15%. This technological advancement not only significantly reduces environmental impacts, but also enhances economic viability by reducing fuel consumption and improving operational efficiency. Complementing this, ref. [58] provide a comprehensive analysis of energy and exergy flows aboard cruise vessels, revealing critical inefficiencies in propulsion and auxiliary energy systems. Their work highlights the need for integrated measurement and modeling techniques to accurately capture energy behaviors, thus informing targeted technology investments.

In conclusion, a robust technological overview of GSC underscores the necessity of integrating sustainable fuel alternatives, optimized energy management technologies, and comprehensive operational practices. Strategic technological investment decisions, informed by rigorous analyses, are vital for advancing maritime decarbonization effectively, aligning industry practices with long-term environmental and economic sustainability goals.

Table 9. Technology adaptation regarding GSC development within the imitation phase.

Technology Adaptation Name	Technology Adaptation Definition	Reference
Zero-Carbon Synthetic Fuels	Adoption of hydrogen and ammonia as zero-carbon synthetic fuels for maritime transport, primarily for domestic and short-sea shipping, characterized by high energy density by mass and favorable environmental profiles despite storage and infrastructure challenges.	Xing et al. (2021) [31]; Nguyen et al. (2023) [50]
Biofuel Hybrid Configurations	Utilization of biofuels blended with conventional fuels, offering commercial attractiveness due to emission reductions, despite challenges like feedstock availability, high production costs, and compatibility issues.	Nguyen et al. (2023) [50]
Waste Heat Recovery (WHR) Systems	Installation of WHR systems onboard vessels, capable of recovering and converting waste heat into usable energy, achieving realistic fuel savings between 5% and 15%, thus significantly reducing both environmental impacts and operational costs.	Baldi and Gabrielli (2015) [52]
Energy and Exergy Analysis Systems	Utilization of detailed onboard energy and exergy analyses to identify inefficiencies within propulsion, auxiliary, and heat recovery systems, guiding technological upgrades to enhance overall vessel energy efficiency.	Baldi et al. (2018) [58]
Intelligent Energy Management Systems	Deployment of advanced energy management technologies, including intelligent monitoring and optimized operational controls for vessel energy use, enabling precise energy efficiency improvements, emissions reduction, and cost management.	Nguyen et al. (2023) [50]
Optimized Fuel Storage Solutions	Strategic utilization and optimization of onboard fuel storage systems, notably cryogenic storage for hydrogen and ammonia, to overcome the storage constraints posed by these fuels’ volumetric energy density, enhancing their feasibility for long-distance maritime voyages.	McKinlay et al. (2021) [56]
Low-Pressure Dual-Fuel LNG Systems	Utilization of low-pressure dual-fuel LNG systems onboard ships as a cleaner alternative to conventional marine fuel oils, significantly reducing environmental impacts and overall sustainability footprint, while maintaining acceptable operational and economic feasibility.	Iannaccone et al. (2020) [35]
Fuel Optimization through Speed Management	Implementation of speed optimization techniques based on predictive modeling (e.g., machine learning), optimizing fuel consumption and significantly reducing CO2 emissions by adjusting sailing speeds according to environmental conditions and operational requirements.	Yan et al. (2020) [41]
Optimized Storage and Operational Practices	Application of operational optimizations such as reducing unnecessary fuel carriage, thus enhancing vessel performance by adjusting fuel storage closer to actual consumption requirements, reducing onboard fuel mass and volume, and consequently enhancing efficiency.	McKinlay et al. (2021) [56]
Onshore Power Supply (OPS) and Electrification	Adoption of electrification initiatives, including shore-to-ship power supplies, vessel electrification, and integration of hybrid propulsion systems, significantly decreasing the environmental impacts of port operations and vessel energy consumption.	Christodoulou and Cullinane (2021) [51]
Cruise Ship Energy System Optimization	Detailed onboard energy and exergy analyses to identify inefficiencies in cruise ships’ propulsion, heat, and electrical systems, supporting targeted interventions for improved sustainability through advanced measurement and modeling approaches.	Baldi et al. (2018) [58]

categorizes a list of technology adaptations regarding GSC development within the initiation phase.

Green shipping corridors (GSCs) are currently in the initiation stage, where the focus is on stakeholder alignment, initial feasibility, and governance structures [11]. The adoption of zero-carbon synthetic fuels, biofuel hybrids, and waste heat recovery systems offers tangible pathways to reduce emissions and optimize operational efficiency. These adaptations, combined with rigorous energy and exergy analyses, can inform a phased roadmap, guiding future expansions of GSC initiatives. By integrating supply chain optimization and digitalization, GSC stakeholders can prioritize resources, foster collaboration, and streamline decision making. This synergy ensures that subsequent phases of development build upon a robust foundation of proven, scalable solutions.

5.3. Stakeholder Collaboration Overview

This stakeholder collaboration overview constitutes key recommendations from relevant and selected articles to highlight the critical role of robust public–private partnerships, cross-value chain coordination, and early stakeholder engagement in advancing green shipping corridors for maritime decarbonization.

Stakeholder collaboration constitutes a foundational element for developing green shipping corridors (GSCs), supported by diverse theoretical insights and empirical studies. Scholars in [55] conduct a Structural Equation Model incorporating stakeholder theory, planned behavior theory, and resource dependence theory. The scholars emphasize that stakeholder pressure impacts shipping companies’ adoption of sustainable practices. Stakeholder influence is not merely a peripheral factor, rather, it directly and indirectly shapes organizational attitudes, behavior control, and business performance. The study identified that bulk shipping companies deal with greater stakeholder pressure compared to container shipping firms, indicating that different shipping segments necessitate tailored stakeholder engagement strategies. Furthermore, larger organizations demonstrate a greater responsiveness and proactive engagement with sustainable practices due to more intense stakeholder scrutiny and higher resource availability, underlining the need for differentiated collaboration strategies aligned with company characteristics.

The authors in [46] extend this perspective by highlighting the pivotal role of stakeholders in adopting green shipping practices (GSPs). The authors note that robust corporate commitment and cross-functional integration promote cooperation among shippers, carriers, and logistics providers, and are essential for reducing environmental impacts of cargo movements. This collaborative approach extends beyond mere compliance with environmental regulations, encompassing proactive alignment of industry norms and responding effectively to evolving customer demands. This aligns with the principles of institutional theory. Institutional theory claims that successful sustainability initiatives result from collective stakeholder pressure—regulatory (coercive), market-driven (mimetic), and industry standard setting (normative).

Empirical evidence from [49] further underscores the strategic importance of stakeholder collaboration through a comprehensive evaluation of shipper loyalty. This research illustrates how sustainable shipping practices (SSPs) bolster perceived value, trust, and reduce transaction costs, thereby enhancing customer loyalty. Such outcomes are achievable only through consistent and meaningful interactions among stakeholders across the maritime supply chain, from shipping operators to end customers. These interactions must deliver clear economic, emotional, quality, and social benefits to foster sustained commitment and loyalty among stakeholders.

Moreover, ref. [53] stress the strategic management of sustainability through systematic resource classification, highlighting that intrafirm resources, interfirm relationship management, and organizational learning resources are interdependent and mutually reinforcing. Stakeholder collaboration, particularly interfirm relationship management, is critical for leveraging relational and contractual governance frameworks and ensuring effective communication across organizations. This multi-dimensional collaboration enhances sustainable shipping management, translating organizational capabilities into superior sustainability outcomes.

Finally, ref. [41] argue for collaborative governance, emphasizing integrated operational strategies such as berth allocation optimization, sailing speed adjustments, and coordinated scheduling among ports and shipping operators. Such collaborative governance mechanisms, supported by appropriate government intervention, foster proactive stakeholder engagement, incentivizing actors within the maritime industry to actively participate in emission reduction and sustainability initiatives.

In conclusion, stakeholder collaboration in GSCs requires comprehensive, strategically aligned approaches informed by stakeholder theory, institutional pressures, and resource interdependencies, ensuring effective implementation and substantial environmental and business performance improvements.

Table 10. Stakeholder mechanisms regarding GSC development within the imitation phase.

Stakeholder Collaboration Mechanism Name	Stakeholder Collaboration Mechanism Definition	Reference
Stakeholder Pressure and Behavioral Influence	Stakeholders exert pressure on shipping firms influencing attitudes and behavioral controls, driving the adoption of sustainable practices directly and indirectly, enhancing overall business performance. Particularly effective in bulk shipping and larger shipping firms.	Yuen et al. (2017) [44]
Cross-Functional Corporate Integration	Collaboration mechanism involving integration of multiple organizational functions and processes, ensuring widespread adoption and successful implementation of green shipping practices (GSPs).	Lai et al. (2011) [46]
Shipper–Carrier Cooperation	Active collaboration between shippers and carriers to reduce environmental impacts, enhance operational efficiency, and jointly adopt green shipping practices, involving alignment with customer demands and industry standards.	Lai et al. (2011) [46]
Interfirm Relationship Management	Collaborative framework including relational governance, contractual agreements, and effective communication channels among multiple organizations, facilitating effective sustainable shipping management and resource exchange.	Yuen et al. (2019) [53]
Organizational Learning Resources	Cross-stakeholder mechanism involving shared knowledge exploitation and exploration, enhancing inter-organizational learning, continuous improvement, and effective application of sustainability strategies within shipping companies.	Yuen et al. (2019) [53]
Collaborative Governance	Structured cooperation mechanism between ports, shipping companies, and regulatory bodies, involving operational integration such as optimized berth allocation, coordinated scheduling, and adjusted sailing speeds to achieve substantial emission reductions and improved operational efficiencies.	Wang et al. (2023) [41]
Voluntary Corporate Sustainability Initiatives	Stakeholder-driven voluntary initiatives integrated into Corporate Social Responsibility (CSR) strategies to proactively address sustainability challenges, including vessel electrification, methanol conversion, and onshore power supply, encouraged by targeted regulatory incentives and supportive collaboration.	Christodoulou and Cullinane (2021) [51]
Customer Engagement and Loyalty Development	Collaborative interactions among shipping operators, logistics providers, and customers, focused on creating tangible economic, emotional, quality, and social benefits to foster sustained customer loyalty and stakeholder commitment through sustainable shipping practices.	Yuen et al. (2018) [49]
Institutional Collaboration Framework	Mechanism grounded in institutional theory comprising coercive (regulatory), normative (industry standards), and mimetic (market-driven) pressures to collaboratively ensure broad adoption of sustainable shipping practices across maritime sectors.	Lai et al. (2011) [46]

categorizes a list of stakeholder collaboration mechanisms regarding GSC development within the initiation phase.

These stakeholder collaboration mechanisms encompass varied approaches for enhancing sustainable shipping. Stakeholder pressure and behavioral influence drive firm attitudes, while cross-functional corporate integration ensures the embeddedness of green practices. Shipper–carrier cooperation and interfirm arrangements improve operational efficiency, aligning industry standards with environmental goals. Relationship management and organizational learning resources fortify knowledge exchange among partners. Collaborative governance fosters joint initiatives among ports, shipping firms, and regulators. Voluntary sustainability efforts and customer engagement further strengthen green adoption. In Europe, such collaboration facilitates policy-driven transitions, whereas Asia is increasingly leveraging cross-sector alliances to address expanding trade networks.

5.4. Extending the Green Corridor Concept: Clarifying Technological Innovations, Policy Reforms, and Stakeholder Collaborations

Green shipping corridors are in the initial phase of a four-stage implementation process, where key stakeholders collaborate to establish a shared vision and identify optimal trade routes for zero-emission shipping [11]. In accordance with [11], the stated phase consists of the following four developmental elements: (1) Stakeholder Workshops; (2) Country-Level Assessment; (2) Formation of Core Stakeholder Group; and (4) Governance Agreed. Figure 5 depicts the four developmental elements of the GSC imitation phase [11].

Figure 5 represents the four developmental elements, briefly discussed as follows [11]. Stakeholder workshops are conducted to exchange ideas, define objectives, and set the foundation for green corridor projects between maritime companies, policymakers, and community leaders. Country-level assessments review national regulations and economic conditions, ensuring that strategic decisions are grounded in real-world policy contexts. Once key insights emerge, a core stakeholder group is formed, representing vital sectors and governmental bodies to spearhead planning and execution. Finally, all parties agree on a clear governance structure, establishing transparent roles, decision-making protocols, and organizational frameworks. This cohesive approach helps to maintain alignment and momentum as green corridor initiatives advance.

Stakeholder Workshops serve as a foundational mechanism for uniting maritime companies, policymakers, and community leaders to exchange ideas and define shared objectives. This aligns with the broader policy impetus emphasizing coordinated governance structures and robust institutional frameworks [46,49]. By harnessing diverse perspectives, workshops create an environment conducive to addressing challenges identified in studies, including the need for technology roadmaps and strategic investment tools. Once these preliminary insights are articulated, the Country-Level Assessment phase scrutinizes national regulations, economic factors, and market conditions [55]. This systematic evaluation ensures that policy recommendations, such as zero-carbon fuel mandates or flexible investment incentives, are matched with actual operational constraints. Together, these activities establish a realistic foundation for expanding green corridor initiatives. Hence, they serve as essential precursors for corridor development.

After deriving critical insights from workshops and assessments, the Formation of a Core Stakeholder Group marks the next strategic milestone. This dedicated coalition, typically comprising industry leaders, government officials, and NGOs, coordinates corridor planning and ensures resource alignment across sectors. Reflecting institutional theory’s emphasis on regulatory, normative, and market-driven pressures [46], the group promotes proactive engagement and fosters cross-functional collaboration. Its tasks include clarifying roles, mobilizing investments for advanced technologies, and drafting guidelines for zero-carbon fuel adoption. Once membership and objectives are finalized, Governance Agreed outlines the corridor’s formal decision-making protocols and accountability structures. This process, supported by flexible decision-making tools [48,54], mitigates risks and encourages iterative policy refinement. Consequently, corridor initiatives can progress with stable oversight and concerted industry compliance.

6. Conclusions

Green shipping corridors (GSCs) are designated maritime routes implemented to promote zero-emission shipping practices via coordinated efforts among stakeholders, innovative technology adoption, and supportive policy frameworks. The main objectives of GSCs are reducing greenhouse gas emissions, fostering sustainable maritime transportation via alternative fuels, and enhancing stakeholder collaboration across the shipping value chain to achieve long-term decarbonization goals.

A search within the Web of Science database via Boolean search term operators resulted in a total of 2238 relevant publications, representing contributions from 654 authors across 93 distinct academic sources. The three most influential articles, determined by local citation counts within the bibliometric analysis, are authored by Xing et al. (2021) [31] with 16 local citations, followed by Lirn et al. (2014) [32] with 10 local citations, and Lun et al. (2014) [33] with 7 local citations. The three leading journals, based on local citations from the bibliometric analysis, are Transportation Research Part D: Transport and Environment (45 citations), International Journal of Shipping and Transport Logistics (21 citations), and Maritime Policy & Management (20 citations). The three most influential articles based on local citation counts are authored by Xing et al. (2021) [31] with 16 citations, Lirn et al. (2014) [32] with 10 citations, and Lun et al. (2014) [33] with 7 citations.

The utilization of the bibliographic coupling technique and equal-weighted average techniques enabled the analysis of a refined dataset consisting of 115 articles, further narrowed into an interconnected subset of 20 highly influential publications. This enabled the formation of the following four distinct research clusters: (1) Sustainable Green Shipping Practices and Research; (2) Alternative Fuels and Low-Carbon Strategies for Maritime Transport; (3) Green and Low-Carbon Maritime Development; and (4) Environmental Sustainability in Maritime Shipping. Cluster 1, “Sustainable Green Shipping Practices and Research”, examines theoretical foundations, such as Stakeholder Theory and Resource-Based Value theory with the aim to advance strategic resource management in order to better explain sustainable shipping practices’ adoption. Cluster 2, “Alternative Fuels and Low-Carbon Strategies”, places emphasis on comparative evaluations and strategic planning towards decarbonization through hydrogen, ammonia, and biofuel alternatives. Cluster 3, “Green and Low-Carbon Maritime Development”, explores industry-wide trends, policy opportunities, and quantitative analyses fostering emissions reductions through coordinated operational strategies and fleet management practices. Cluster 4, “Environmental Sustainability in Maritime Shipping”, focuses on IMO orchestration frameworks, investment decision-making tools, and technological adaptations, such as real options analysis and waste heat recovery systems, acting as emerging technologies that require investigation regarding widespread adaptation.

Cross-cluster commonality emerges from three core methodological approaches within the main clusters’ subclusters. First, advanced quantitative modeling techniques—such as energy systems modeling, multi-criteria decision analysis, and machine learning—evaluate technical performance and emission reductions. Second, decision support frameworks, including real options analysis and resource-based methodologies, optimize investment risks and resource allocation. Third, integrated environmental performance evaluations using energy efficiency and exergy analysis metrics unify technical and strategic assessments. These approaches collectively bridge diverse research clusters, offering comprehensive insights that advance our understanding of sustainable shipping practices and green corridor development.

Content analysis from the clusters revealed 10 possible policy recommendations, 11 technology adaptation recommendations, and 7 proposed stakeholder collaboration mechanisms.

The 10 possible policy recommendations are listed as follows. Policies should establish robust institutional frameworks that reinforce regulatory compliance and the standardization of green shipping practices. The integration of adaptive decision-making tools, such as real options analysis, aids in mitigating investment uncertainties in sustainable maritime technologies. Policies must also incorporate quantitative assessment methods to systematically evaluate both the environmental and economic outcomes of sustainability initiatives. Additionally, zero-carbon fuel transition policies are necessary, particularly encouraging the adoption of and infrastructure for hydrogen and ammonia fuels aligned with decarbonization goals. Supporting voluntary corporate sustainability initiatives with economic incentives can further enhance industry engagement. Collaborative governance frameworks promoting coordinated operational strategies between ports and shipping companies should be emphasized. Strategic policies must align technological roadmaps with international decarbonization targets, ensuring long-term planning consistency. Operational infrastructure development policies should cater specifically to diverse technological and vessel-specific requirements. Cross-functional integration policies should facilitate cohesive efforts across the maritime sector. Lastly, multidisciplinary policies must integrate institutional, technological, economic, and environmental objectives to achieve comprehensive sustainability transitions.

The 11 revealed technology adaptation recommendations are as follows. Maritime decarbonization efforts should adhere to the adoption of zero-carbon synthetic fuels, such as hydrogen and ammonia, along with biofuel hybrid configurations to manage emission reductions effectively. Emerging technologies in terms of waste heat recovery (WHR) systems and detailed energy and exergy analysis methods provide the possibility for favorable energy efficiency onboard vessels. Intelligent energy management systems, optimized fuel storage solutions, and low-pressure dual-fuel LNG systems further support operational sustainability. Optimizing fuel use through vessel speed management, strategic storage practices, and enhanced operational procedures offer substantial emissions and efficiency benefits. Finally, investments in onshore power supply (OPS) and electrification, together with comprehensive cruise ship energy system optimization, provide critical pathways to achieving zero-emission maritime transport.

There are seven proposed key factors for effective stakeholder collaboration. Achieving successful collaboration requires a depth of theoretical integration, combining stakeholder, planned behavior, and resource dependence theories to clearly define collaborative frameworks. Differentiated stakeholder strategies should be tailored to organizational characteristics and specific shipping sectors, ensuring targeted engagement. Strategic and operational integration promotes alignment across maritime supply chains, incorporating both corporate commitment and coordinated operational activities. Institutional perspectives emphasize the influence of regulatory, normative, and market-driven pressures on collaboration. Resource management facilitates interfirm and intrafirm interactions, enhancing shared capabilities. Clearly defining comprehensive outcomes and benefits, including economic, social, and environmental impacts, strengthens stakeholder commitment. Lastly, ensuring clarity and cohesion in collaboration strategies promotes unified understanding and consistent implementation across stakeholders.

Collectively, these 28 recognized recommendations aim to provide a comprehensive framework to better understand and effectively implement green shipping corridors, fostering maritime sustainability.

Furthermore, the four elemental developmental pillars for green corridor initiatives include Stakeholder Workshops, Country-Level Assessments, Formation of a Core Stakeholder Group, and Governance Agreed. Stakeholder Workshops unite maritime companies, policymakers, and community leaders to share ideas and set collective objectives. Country-Level Assessments rigorously examine national regulations, economic conditions, and market dynamics, ensuring that policy recommendations are realistic. The Formation of a Core Stakeholder Group creates a dedicated coalition that coordinates planning and mobilizes investments, fostering cross-sector collaboration. Finally, Governance Agreed establishes clear decision-making protocols and accountability structures, enabling iterative policy refinement and stable oversight for the successful expansion of green corridor initiatives.

The recommendations for scholars and industry practitioners are as follows. Scholars should empirically validate these identified policy, technological, and stakeholder collaboration recommendations through comparative and longitudinal studies, utilizing interdisciplinary methods from institutional, behavioral, and strategic management theories. Industry practitioners are advised to apply these insights, aligning operations with sustainability goals, proactively engaging stakeholders, and investing in validated technological innovations. Furthermore, collaboration between scholars and industry practitioners is essential for fostering the implementation and monitored improvement of green shipping corridors. One limitation of this study is its reliance on a predominantly bibliometric methodological framework without incorporating qualitative insights from case interviews or data from patents and industry reports. Future research should integrate these mixed methods to provide a more comprehensive analysis of green shipping corridors, thereby advancing both theoretical understanding and practical applications of the concept.