Navigating Sustainability: The Green Transition of the Port of Bar

Abstract

The shift to green ports is essential for meeting worldwide sustainability targets and lowering emissions related to maritime activities. This paper presents a comprehensive analysis of the Port of Bar in Montenegro and its prospects for transforming into a low-carbon sustainable port hub within the Adriatic region. By a mixed-method approach consisting of empirical data, theoretical modeling, expert interviews, and other relevant methodologies, the study designs a comprehensive roadmap for the port’s multi-phase green transition. The first phase (2026–2030) focuses on partial electrification of cargo handling equipment, installation of on-site photovoltaic systems, and modernization of the Port Community System (PCS) to improve efficiency and environmental monitoring. The second phase (2030–2038) includes full electrification of port operations, Onshore Power Supply (OPS) accessibility for vessels at berth, and full renewable resource adoption. Results indicate the measures can significantly reduce annual CO₂ emissions during the first phase, with a long-term potential to attain net-zero emissions. This transformation is in line with international regulations, European Union policies, as well as Montenegro’s national strategies and policies, positioning the Port of Bar as a regional model for green port development.

1. Introduction

In recent years, the transition to renewable energy sources and energy efficiency have become the center of priority, not only for both global policy makers and port communities but also for scientific researchers [1,2]. Such a focus is directly related to the growing global concern about climate change, which has positioned itself as one of the most urgent challenges of the twenty-first century [3,4]. If we take into account that the transport sector accounts for almost one fifth of global greenhouse gas (GHG) emissions, then we can also conclude that port decarbonization is a key step towards achieving broader climate goals [5,6]. The maritime industry, including ports and shipping, contributes approximately 3% of total global GHG emissions, and predictions indicate that this proportion will increase significantly in the absence of coordinated mitigation strategies [7,8]. Forecasts such as the International Transport Forum (ITF) baseline scenario predict that shipping-related emissions could reach 1090 million tons of CO₂ by 2035, an increase of around 23% compared to the levels we had in 2015 [9]. Similar projections within the IMO framework point out that limited adoption of cleaner fuels and slow progress in energy efficiency could further accelerate this trajectory [10].

Figure 1 illustrates projected CO₂ emission trajectories for the shipping sector through 2035.

We are witnessing that ports are working under much greater pressure today, which is not only a result of global climate agreements, such as the Paris Agreement within the UNFCCC [11], but also due to increasing, and equally justified, social expectations for transparency, responsibility and environmental performance [12]. Consequently, sustainability is no longer seen as a requirement for business compliance but as a strategic opportunity to improve competitiveness and financial performance through energy optimization and the use of renewable technologies [13]. Such a turn in business, or change, is strongly supported by the European Union’s regulatory framework for sustainable transport [14] as part of its comprehensive goal of achieving climate neutrality by the middle of this century [15].

The port of Bar, the main maritime gateway of Montenegro, is offered as an instructive case study for the analysis of the practical dimensions of this transition [16,17]. Despite its relatively small size, the port has significant potential for “green” transformation, especially due to its geographical location, infrastructure and intermodal connectivity [18]. Unlike larger and more financially autonomous ports in Western Europe, Bar operates under unique geopolitical and economic conditions and influences within the Eastern Adriatic region, which is largely characterized by limited access to financing, transitional energy systems and moderate cargo flow. However, precisely because of these structural limitations, the Port of Bar represents a unique and relevant model for research that aims to show how small and medium-sized ports can, with a good strategy, realistically strive for complete decarbonization with minimum maintenance, although the authors also consider an increase in operational and financial stability.

Figure 2 provides an aerial overview of the Port of Bar, Montenegro, illustrating its port infrastructure and surrounding area.

European ports such as Koper and Gothenburg, which have successfully implemented systems for coastal power supply, port electrification and energy management [19,20], serve as reference examples and provide valuable guidelines for adaptation. It is also inevitable that the inclusion of the Port of Bar in the Trans-European Transport Network (TEN-T) via the railway and highway corridor Belgrade–Bar and further towards the continental part of Europe will further strengthen its strategic importance for the sustainable development of transport in the region [21].

This study responds to an identified research gap by developing a context-sensitive, two-phase transition roadmap, specifically tailored to the Port of Bar.

The first phase emphasizes the need for operational optimization where, through a partial transition, a significant reduction in pollution and improved energy management is achieved, while the second phase focuses on long-term investments in the integration of fully renewable energy sources, sustainable infrastructure development, digitization and achieving the desired goal of net-zero emissions.

These two interconnected phases are evaluated through several dimensions of sustainability in

Table 1. Impact of the transition measures on sustainability dimensions.

Key Measure	Environmental Impact	Port Operations Optimization	Economic Impact
Theoretical and Regulatory Framework	Eco-friendly practices	Integration of “green” criteria	-
Designing a phased approach	Sustainability	Digitalization and modernization	Long-term investment attractiveness
Monitoring and Evaluation	Continuous improvement	Real-time decision making	Budgeting and resource management

(Impact of the transition measures on sustainability dimensions).

Based on empirical operational data, expert consultation and interviews and a realistic assessment of financing mechanisms, including EU funds, state subsidies and revenues that the Port of Bar can achieve during the transition period in these two phases, the study seeks to answer two central research questions.

• Which combination of technological, operational and management measures provides the greatest feasibility and impact for the decarbonization of a small Adriatic port under existing constraints?
• How can these measures be sequentially implemented in order to ensure long-term financial, technical and institutional sustainability and at the same time complying with the European climate goals [13,15]?

In order to ensure proper implementation and real-time monitoring of key indicators, a digital system is used based on proven global solutions that will also be adapted to the needs, infrastructure constraints and strategic goals of the Port of Bar.

2. Literature Review

In light of contemporary research, it has become increasingly clear that port transition towards sustainability and digital transformation are crucial to reducing environmental harm and enhancing competitiveness. This shift aligns with international climate targets set out by the Paris Agreement [3,4] and increasingly strict EU policies in the field of maritime transport [13].

The academic discourse on port sustainability has made significant strides, but the majority of attention remains focused on large, well-funded European ports. Key theoretical models, empirical examples and innovative practices indicate that small and medium-sized ports, like the Port of Bar, must combine green technologies, digitization and regional cooperation to be part of global supply chains with reduced emissions [1,15].

The literature in this review combines theoretical contributions, empirical findings and performance assessment frameworks to explain the relationship between sustainability and digitalization in the maritime domain while also highlighting research gaps and opportunities for smaller ports.

By synthesizing theoretical perspectives, empirical evidence and performance evaluation frameworks, this literature review clarifies the evolving relationship between sustainability and digitalization in the maritime sector while identifying existing research gaps and outlining future opportunities for small and medium-sized ports.

2.1. Theoretical Background

The theoretical framework of the green transition of the port relies on the principles of sustainable development, ecosystem approach and circular economy. Schlüter et al. [15] analyze land–sea interactions through an evolutionary governance perspective, while Ringbom [13] explains the legal aspects of EU maritime policy. Bodansky [3] and Pauw et al. [4] indicate the legal nature and conditions of fulfillment of Nationally Determined Contributions (NDC) in the context of the Paris Agreement.

Acciaro [1] emphasizes the new role of port authorities as drivers of energy efficiency, and Satır and Doğan-Sağlamtimur [2] develop the concept of the Eco-Port model, which integrates the protection of marine ecosystems into port operational strategies.

The digital component becomes an integral part of theoretical models underpinning port decarbonisation and smart transition. Bichou [22] and Bentaleb et al. [23] address the standardization of KPI indicators, which forms the basis for monitoring the progress of the green transition.

However, the operationalisation of such KPI in real time requires reliable and resource-efficient sensor and communication layers. In this context, Pensieri et al. [24] provide empirical validation of LoRaWAN technology as a viable, low-power wireless infrastructure for IoT applications in maritime environments. Extending this technological layer to the level of strategic transformation, Wan et al. [25] argue that digitalisation goes beyond mere instrumentation, fundamentally reshaping port governance structures and investment decision-making. This enables the adoption of predictive analytics and dynamic resource allocation, transforming static decarbonisation targets into adaptive, data-driven processes.

Perera et al. [26] analyze contextual data processing for Internet of Things (IoT) applications, while Frontiers in Energy Research [27] highlights the importance of digital twin technology for port energy systems. Zhou et al. [28] develop the architecture of smart ports in the era of Industry 4.0.

2.2. Empirical Evidence on Port Sustainability

Examples from practice confirm theoretical guidelines through concrete results. The Port of Rotterdam is continuously investing in digitization and decarbonization projects [21], while the Port of Antwerp–Bruges is developing electrification and equipment conversion strategies [20]. The Port of Gothenburg is leading the way in the implementation of shore power solutions, reducing emissions during the stay of ships in port [19].

The example of the port of Koper [16,17] shows how the Port Community System can be developed to monitor sustainability. Campos [6] points to the challenges of security and environmental protection in Latin American ports, while Stalmokaitė [29] analyzes innovative practices in Klaipeda and Stockholm. Elsayeh et al. [30] investigate the competitiveness of hub ports in the Mediterranean.

Gularte Quintana et al. [31] and Acuña et al. [32] present innovations in the environmental management of ports in Brazil and the Caribbean. Chung Ee Yong [33] uses an agent-based model for sustainable equipment expansion, while Itumeleng Greta Motau [34] examines the productivity of African container terminals. Azarkamand et al. [5] offer an overview of initiatives to reduce CO₂ emissions, and Lee and Song [7] link container shipping to global supply chains.

Brunilla et al. [14] develop a tool for self-monitoring the sustainability of small ports. Sim et al. [35] demonstrate AI Smart Port Logistics Metaverse on the example of Busan port. Haynes Salmon [36] indicates the level of knowledge of environmental regulations in Central American port states. Caramuta et al. [18] deal with an integrated evaluation of the transport policy in the port of Trieste.

2.3. Port Performance and Innovation

The assessment of port performance is based on a wide range of indicators, including energy savings, CO₂ emissions, digitization and the application of smart technologies [22,23]. Mendes Constante [37] describes international examples of the implementation of Port Community Systems, while Heilig et al. [38] analyze the historical development of digital transformation.

The application of blockchain [39] and digital twins [27] optimizes data flows and reduces operational costs. Martide [40] provides an overview of the key elements of smart ports, while Perera et al. [26] and Zhou et al. [28] point to the importance of IoT infrastructure.

Karolina Luoma et al. [41] explore the perceptions of local stakeholders in small ports, while Wan et al. [25] summarize the innovations and challenges for transitioning ports to a low-carbon future.

2.4. Identified Research Gaps

Although many large ports are studied in detail, there is a dearth of literature on small and medium-sized ports in the Adriatic basin. Authors like Azarkamand et al. [5] and Campos [6] emphasize the need to apply advanced methods to reduce emissions and integrate digitization in ports with limited resources. Haynes Salmon [36] and Stalmokaitė [29] emphasize regulatory challenges, while Karoliina Luoma et al. [41] emphasize the importance of involving local users.

Previous research on sustainable port development has been largely focused on major international ports, while studies addressing sustainability models in small and medium-sized ports remain limited.

Despite the growing application of digital twins, blockchain and AI solutions, their application in smaller ports is still limitedly documented [28,35].

While several studies have examined partial aspects of port sustainability such as energy efficiency, digitalization and renewable energy integration, comprehensive frameworks addressing full port decarbonization remain scarce, particularly within the Eastern Adriatic and Western Balkans region. Montenegro, despite its strategic maritime position and EU accession trajectory, has yet to initiate a structured decarbonization process for any of its ports. Existing regional examples, such as the Port of Koper in Slovenia and the Port of Rijeka in Croatia, have introduced limited pilot measures, including photovoltaic systems, electrified handling equipment and environmental monitoring initiatives. However, no port in this area has achieved or modeled a holistic transition pathway towards carbon neutrality.

Due to substantial differences in organizational capacity, technological advancement and financial resources between large and smaller ports, the applicability of existing sustainability strategies to small and medium-sized port systems remains uncertain. This underrepresentation reveals a research gap in understanding the key factors that shape sustainable practices in smaller ports. It is therefore essential to identify which technological, economic, and institutional components enable these ports to successfully implement green and digital transition processes. This study contributes to closing that gap by proposing a sustainable model that connects environmental objectives, digital technologies, and governance mechanisms specifically adapted to the operational realities of small and medium-sized ports.

Accordingly, this paper aims to fill this gap by analyzing the potential of the Port of Bar to become a regional “green port” and a reference model for the sustainable transformation of small and medium-sized ports in the Mediterranean.

3. Materials and Methods

A comprehensive methodological approach that integrates empirical data analysis, theoretical modeling and expert consultation was required in the creation and development of a sustainable transition model for the Port of Bar.

The collection of primary and secondary sources of data was carried out systematically, after which they were verified and comparatively analyzed in order to ensure the reliability and applicability of the results.

3.1. Data Collection and Empirical Modeling

The empirical modeling component relied on the verified internal documentation of the Port of Bar, which includes the Business Plan for 2025 and Management Business Reports covering the period from 2022 to 2024.

By reviewing the business plan and technical documentation of the Port of Bar, key data concerning port infrastructure, port operational equipment, operational practices and data concerning operational and other port costs were identified.

The analysis enabled an objective assessment of current operational performance and the identification of priority areas with the greatest potential for decarbonization and process optimization.

3.2. Theoretical Modeling and Scenario Design

The theoretical modeling framework was applied to conceptualize two time periods, that is, two development phases, the ultimate and main goal of which is to achieve a net-zero-emission port model based on the principles of low-carbon operations and smart technologies.

An optimization approach based on scenarios and principles of sustainable logistics was developed and aligned with the goals of the European Green Plan and the “Fit for 55” legislative package. Three transition scenarios were formulated.

• The basic scenario, which reflects the current operating conditions;
• The medium scenario, which includes partial electrification and integration of renewable energy sources;
• An advanced scenario targeting the complete decarbonization and digitization of port operations.

Each scenario was assessed using a set of environmental, operational and economic performance indicators, allowing for a comprehensive evaluation of their practical implications.

To ensure the reliability of the proposed model, a sensitivity analysis was conducted, exploring how changes in energy prices, technology costs and renewable energy generation potential could influence the projected results.

3.3. Expert Consultation and Qualitative Validation

The key qualitative component of the mixed-method framework was the process of consultation and expert interviews. Semi-structured interviews were conducted with eleven experts grouped into three stakeholder groups, namely port and terminal management (five experts), the renewable energy and technology sector (three experts) and the academic community specialized in sustainable transport and logistics (three experts).

The criteria taken into account in the selection included primarily professional relevance, expertise in the field and at least five years of professional experience. The participants were between the ages of 35 and 55, with a master’s or PhD degree, which ensured diversity and credibility of perspectives.

The interviews explored three main thematic dimensions: the technical feasibility and infrastructure readiness of the proposed measures, their economic and financial viability, and the effectiveness of existing regulatory and institutional frameworks. Each session combined open-ended dialogue with structured ranking exercises, ensuring that expert perspectives were systematically translated into measurable prioritization criteria.

The collected insights were subsequently synthesized using a weighted approach based on the Analytic Hierarchy Process (AHP), which provided a transparent and evidence-based foundation for developing the two-phase roadmap outlined in the Results Section 4.

3.4. Integration of Findings and Methodological Framework

Secondary data obtained from international literature, case studies and comparative analyzes complemented the primary findings.

The focus of attention was directed to the collection and analysis of data from those Mediterranean seaports that have already launched certain programs of decarbonization and digital transformation, because such data provide reference values for assessing the feasibility of similar interventions in the Port of Bar. This triangulation of data sources improved the validity and contextual relevance of the proposed model.

The overall methodological framework followed the principles of operational research and green logistics, ensuring decision-making based on empirical evidence and sustainability-oriented optimization.

The analysis considered the relevant, primarily national and of course European regulatory frameworks that regulate the sustainable development of ports, with special attention to climate change mitigation, energy transition and regional cooperation within the Adriatic basin.

The three main methodological objectives and their multidimensional impacts are summarized in Table 1, which illustrates the relationship between environmental benefits, operational efficiency and long-term economic attractiveness.

4. Results

In order to enhance the efficiency of port operations, and at the same time achieve the required ‘’green’’ transition, a shift in the operation and business practices of the Port of Bar needs to be carried out in two phases. The first, so-called Pilot phase is projected for the period from year 2026 to 2030 and it encompasses the so-called Moderate Transition. The second phase, the so-called Ambitious Transition, is projected until 2038. Both phases will be accompanied by monitoring and evaluation process that would provide some specific results after certain applied measures and indicate some possible areas for improvement [23]. That way, we would carry out the ‘on-scene’ update if the results show that, and as a final step, if it is necessary, we would carry out the revision/update of the second phase.

For the implementation of the above mentioned phases and the transition process itself, cooperation with the Government of Montenegro is needed, as well as with all of its relevant ministries and EU offices, and is of essential importance. Equally important are transparency of the process and the inclusion of experts and other stakeholders, particularly through public consultations and discussions [15]. Such a transition would completely have to rely on the relevant policy frameworks and EU directives, particularly within the context of climate change mitigation and regional cooperation.

Figure 3 shows the key steps towards the transition of the Port of Bar.

Figure 4 provides a more detailed overview, breaking down the previously mentioned targets into a series of individual steps that need to be addressed on the path toward the desired transition of the Port of Bar. In order to enable the implementation of the first phase, the so-called Pilot phase, it is necessary to previously identify national and international guidelines, as well as EU directives that have an effect on the development of sustainable ports, specifically relating to our case of the Port of Bar. Moreover, before the start of the Pilot phase, it is necessary to design a monitoring and evaluation plan (M&E) in order to establish precise M&E indicators and to be able to evaluate outcome-related information [24].

4.1. Theoretical and Regulatory Framework

The operations and business activities of the Port of Bar are in compliance with national regulations. Montenegro, which aspires to be a next member state of the EU, is harmonizing its legislative framework with EU directives concerning, among other things, climate and energy [42].

In 2017, the Port of Adria, as one of two operators in the Port of Bar, launched a project funded by the European Bank for Reconstruction and Development (EBRD). The project was categorized B in line with the 2014 Environmental and Social Policy. The project includes the purchase of new equipment, upgrade of existing quay wall and a social program related to the ongoing reduction in the workforce and a comprehensive training program in health and safety, operational excellence and commercial/corporate identity may result in environmental and social impacts, which can be readily identified and mitigated through application of relevant environmental and social management practices [42].

The Port of Bar is a part of the EU-funded SUPAIR project [43], which enabled the creation of action plan for a sustainable an low-carbon port model [44].

4.1.1. International Regulations and Conventions

When we talk about international regulations and conventions in the context of preventing and reducing sea and air pollution, the International Convention for the Prevention of Pollution from Ships (MARPOL Convention) comes first on the list [45]. The relevance of the MARPOL Convention is also indicated by the fact that this convention serves as a reference framework for the adoption of national laws and EU directives [13,46]. The convention consists of six technical annexes, all of which are signed by Montenegro [47]. There are countless relevant scientific research papers on the impact of the MARPOL Convention by authors from all over the world, and therefore we will not talk about it in this paper.

Montenegro is also a signatory to numerous other international conventions, including the Paris Agreement, an agreement that is a legally binding international treaty on climate change [11], which we will talk about below. Although there is no international one, the EU Green Deal [48] and the Fit for 55 Package [49] have a strong regional impact on the ports of the Adriatic region, including the Port of Bar.

• The Paris Agreement

The Paris Agreement is a landmark in the multilateral climate change process because, for the first time, a binding agreement brings all nations together to combat climate change and adapt to its effects [3,11]. A great number of countries still do not have adequate capacities where they could properly keep up with the challenges that come with climate change [4,50]. Therefore, what this agreement particularly emphasizes is the need to develop those capacities of the developing countries. That is why developed countries, signatories of this agreement, should have a big role in this. They should offer support to developing countries so that they too can effectively implement adaptation and mitigation measures. The agreement defines a vision for the development and transfer of technologies in order to improve resistance to climate change and at the same time reduce GHG emissions [51]. Such a framework provides concrete guidelines for a more efficient functioning of the technological mechanism. As large financial resources are needed to finance climate activities, the Paris Agreement reaffirms that developed countries should provide financial assistance to developing countries [11,52]. Also, an invitation was sent to all interested parties to voluntarily participate in such a process.

• European Green Deal

Turning Europe into the first climate-neutral continent in the world is a legally prescribed goal stemming from the EU Climate Law [53]. The EU Green Deal is designed to contribute to the creation of new innovative and investment opportunities [48].

All 27 states that are EU members have committed to turn the European Union into the first climate-neutral continent by 2050 [53,54]. In order to achieve this, they have signed to reduce emissions by at least 55% compared to 1990 levels by 2030 [48].

This agreement defines legal frameworks covering key sectors of the economy, with the aim to achieve the EU’s long-term climate goals. The overall package includes the following:

• Emissions reduction targets across a broad range of sectors;
• A target to boost natural carbon sinks;
• An updated emissions trading system to cap emissions, put a price on pollution and generate investments in the green transition;
• Social support for citizens and small businesses.

As far as the financial aspect is concerned, the amount of EUR 86 billion is intended to support the green transition process, of which EUR 65 billion will be allocated from the EU budget [48,55]. This financial injection aims to reduce “enerpoverty” (energy poverty), and at the same time it wants to achieve better competitiveness of European companies.

• Fit for 55 Package

The “Fit for 55’’ package encompasses an array of legal measures directed at strengthening EU system of emission trade (EU ETS), including the enhancement of their function and extension to the maritime sector [49,53]. These measures are fulfilled with new regulations which additionally ensure the efficient implementation of the EU’s climate policy [49].

One of the key elements of the package is the regulation on EU Carbon Border Adjustment (CBAM), which aims to preserve the competitiveness of European producers by determining the price of emissions of imported products [56]. Also, a regulation on the Social Climate Fund is foreseen, whose task is to mitigate the social effects associated with the extension of the EU ETS to the road transport and construction sector [49,53].

Figure 5 illustrates the legislative initiatives related to the EU ETS in the “Fit for 55” package.

In order to align the transport sector with the EU’s climate goals, maritime and road transport are included in the EU ETS system [49,57]. The proposed measures are aimed at increasing the price of GHG emissions in the transport sector. The Renewable Energy Directive prescribes requirements for the use of renewable fuels in road transport [49,58], and a mechanism for the promotion of electromobility has been introduced [59,60]. Special legal acts deal with the reduction in emissions and the provision of alternative fuels in the sub-sectors of road and maritime transport, as well as the aviation industry.

Figure 6 illustrates the transport-related legislative initiatives related to the EU ETS in the “Fit for 55” package.

4.1.2. Identification of National Laws and Strategies

As previously stated, Montenegro, as a potential candidate for EU membership, aligns its laws to the laws of the EU. Other than legal frameworks and strategies, such as the Law on Environment [61], Law on Environmental Impact Assessment and Law on Strategic Environmental Impact Assessment [62,63], Law on Integrated Pollution Prevention and Control [64], Law on Environmental Noise [65], Law on Air Protection [66], Law on Industrial Emissions [67] and Transport Development Strategy of Montenegro [68], regulations and strategies listed below have an essential significance for the transition of the Port of Bar. Not only do they offer legal basis for the transformation of port operations, but they also provide an operational framework for implementation of ‘green’ technologies and enhancement of efficiency. They represent the regulatory framework, i.e., the basis for defining the future course of transition.

• The Law on Energy Efficiency

The Law on Energy Efficiency, authored by the Ministry of Economic Development, according to article 54 of the mentioned law, became effective on 1 May 2011 [69].

The subject matter of this law is defined in Article 1, which states that the objective of this law is to regulate the way of using energy more efficiently, to introduce measures that will lead to improvements in energy efficiency and address other matters relevant to the field of energy efficiency.

In Article 17 of the mentioned law, it is stated that public enterprises, as well as other public sector entities, are required to manage energy use in the facilities where they perform their functions. The aim of this is not only to support activities focused on improving energy efficiency, but also to include raising employee awareness of energy efficiency measures and their implementation, as well as the establishment and application of energy efficiency criteria in the procurement of goods and services.

• The Strategy for the Development of Montenegro’s Energy Sector by 2030

The Strategy for the Development of Montenegro’s Energy Sector, authored by the Ministry of Economic Development in cooperation with international partners, was published in May 2014 [70]. It explores various options for the development of the energy system.

This strategy addresses measures and provides suggestions that, among other things, concern large energy consumers such as the Port of Bar. It also includes specific programs and a wide variety of promotional schemes which include technical assistance, subsidized energy audits and economic incentives.

The main recommendations of this strategy in the field of energy efficiency, which relate specifically to the Port of Bar, are presented in

Table 2. Energy efficiency—the main recommendations of the strategy [70].

Focus Area	Energy Efficiency Actions/Measures
Across all consumption sectors	Promotion of Energy Serving Companies (ESCO), public–private partnerships in the field of energy efficiency, energy audits, consulting services, etc. Establishing incentive schemes to support investments in the field of EE.
For large energy consumers	Technical assistance and other forms of support for improvement of EE for large energy consumers. Voluntary contracts with major energy users for the implementation of targeted EE measures.
Additional measures for small and medium sized enterprises	Specific programs intended for enhancing the use of certain technologies of EE/OIE (for instance, the introduction of integrated energy management systems in facilities, improvement of boiler efficiency, combined heat and power production, heat recovery, large-scale solar thermal systems, the use of biomass, and similar measures). Programs that refer to particular subsectors such as hotels, shopping centers, industrial companies, etc.

:

The main recommendations of this strategy in the field of renewable energy sources, which relate specifically to the Port of Bar, are presented in

Table 3. Renewable energy sources: the main recommendations of the strategy [70].

Focus Area	Key Actions/Measures
Investment support	Continuously monitor the conditions for the use of renewable energy sources, adjust the guaranteed incentive tariffs and other conditions if needed and analyze the technical requirements for grid connection and the operation of the power system (EES), as well as the financial impacts on electricity consumers. Provide support for investments that relate to OIE for financially sustainable criteria. Promote investments in renewable energy sources without guaranteed incentive tariffs, in case there are interested investors and provided that there is a possibility for that in the electric power system.
Sun radiation	Promote the use of photovoltaic plants in cases where there is no access to the distributive net. Promote electrical energy produced from the photovoltaic plants with sustainability criteria. Promote the construction of photovoltaic plants without the obligation of guaranteed electricity purchase through feed-in tariffs. Promote the use of solar thermal energy in households and service sector. Promote industrial partnerships in solar technology, the formation of joint enterprises, and collaborative project implementation.

.

• The National Strategy for Sustainable Development by 2030

The strategy for sustainable development, authored by the Government of Montenegro, in cooperation with international partners (EU, UN, WB, etc.) represents a plan for the long-term progress of Montenegro, by which some solutions for sustainable management of national resources are defined [71]. These include human resources, as well as social, natural and economic resources, all of which represent a priority of overall sustainable development of Montenegro’s society.

Some of the most significant measures that directly or indirectly affect the transitional development of the Port of Bar are listed below.

• Increase the share of renewable sources of energy and promote rational use of them, with the following stated as the target outcome for 2030:

  -

  The level of GHG emissions by 2030 is reduced by 30% in comparison to 1990 level;

  -

  Achieved national target of renewable energy sources share in gross final energy consumption of 33% in 2020 and set a more ambitious goal for 2030;

  -

  Achieved indicative target of energy efficiency (9% by 2018) and set a more ambitious goal for 2030;

  -

  Increased fiscal and regulatory incentives for renewable energy promotions and energy efficiency.

• Establish an eco-fund and promote the mobilization of financial resources for sustainable development, including new economical instruments (such as green fiscal reform), with the following stated as the target outcome for 2030:

  -

  Established eco-fund;

  -

  Responsible public consumption, in accordance with the principles of sustainable development;

  -

  Predictable public finance and credible mid-term planning, along with measurement of the effects of consumption, improvement of the country’s credit rating, and support for the development of the green economy.

• Provide financial support for the development of mechanisms and capacities to introduce green economy within ten priority sectors, where among others, the following sub-measures are listed:

  -

  Development of sustainable renewable energy sources and reduction of emissions and environmental pressures;

  -

  Energy efficiency;

  -

  Sustainable production and consumption for efficient use of resources and strengthening the competitiveness (manufacturing industry, services, small and medium-sized enterprises).

The main outcomes for 2030 are listed below.

• Secured domestic and international private sources of financing for sustainable development and the creation of green jobs;
• Improved policy coherence for sustainable development, including enhanced coordination.

Maritime Economy Development Strategy 2020–2030 with the 2020–2021 Action Plan.

The Maritime Economy Development Strategy, authored by the Ministry of Transport and Maritime Affairs, aims to identify and clearly define the key directions for the development of the maritime economy sector in Montenegro [72]. Through the creation of the strategy, efforts are being made to strengthen the role of the maritime industry in the overall economic development and increase the competitiveness of the country, through the establishment of a clear maritime policy and the promotion of sustainable development initiatives.

This strategic document defines operational goals, in addition to strategic ones. The strategic goal represents the result that is to be achieved in the field of public policy at the state level by implementing this strategy. The operational goal is a concrete result that is to be achieved within the framework of the strategic goal with activities planned in a certain period of time (until 2030).

Identified key activities, which specifically relate to the Port of Bar, are shown in

Table 4. Strategic and operational goals [72].

Strategic Goal	Operation Goal	Activities
Increasing the contribution of the maritime industry and related activities to the overall economic development	Achieving sustainable growth and competitiveness in the port sector	Reconstruction and modernization of current port capacities (2030) Construction of a new container terminal in the Port of Bar that would position the Port of Bar as the one of regional importance (2030) Development of intramodality and accessibility through the construction and modernization of the road and railway infrastructure, aiming to achieve enhanced connectivity of Montenegro’s ports with the hinterland and solving bottlenecks in the road infrastructure (2030) Plan on an annual basis for which port services and infrastructure projects the procedure for awarding a concession or establishing a private-public partnership will be initiated, all with the aim of encouraging investments in the maritime economy, improving the efficiency and quality of the provision of port services, which will ultimately contribute to the competitiveness of Montenegrin ports (2030) Encourage the construction of the Port LNG terminal (2030)
Development of maritime industry is based on the principles of the green economy	Create prerequisites in the public and private maritime sector for economic growth based on the principles of the green economy	Encourage the development of new technologies and continually monitor and enhance knowledge, rules and regulations aimed to prevent pollution of the sea environment that can be caused by shipping and port activities, exploitation operations, hydrocarbon exploration and the installation of submarine pipelines, cables and other installations (2030)

.

An analysis of benefits that the Port of Bar would realize by making it coherent with national laws and strategies, and which are of great importance both for the first Pilot and for the second ambitious phase, is described in

Table 5. Direct benefits for the Port of Bar derived from national legal and strategic frameworks.

Law/Strategy	Specific Benefits for the Port of Bar
Law on Energy Efficiency	Eligibility for state-supported energy audits and staff training Access to national funding for implementing EE measures
Energy Development Strategy of Montenegro until 2030	Technical assistance for EE improvements in port operations (e.g., LED lighting, electric motors) Participation in subsidized energy audits Possibility to sign voluntary EE agreements with the government Access to programs for installing photovoltaic systems and using biomass for auxiliary facilities
National Strategy for Sustainable Development until 2030	Financing of projects through the eco-fund (e.g., solar installations on warehouses, purchasing the new equipment) Access to tax and regulatory incentives for green investments Opportunity to create green jobs (e.g., EE engineers, OIE technicians) Advantage in applying for public projects related to green economy in transport State and EU support for reconstruction and modernization of terminals Participation in LNG terminal development to become a regional clean fuel hub Access to funds for electrification and modernization of port equipment Involvement in public–private partnerships (PPP) and concession-based infrastructure projects

.

It is especially important to note once again that the achievement of the set goals depends to a large extent on the active cooperation of the Port of Bar with international partners, the Government of Montenegro and all competent ministries in order to make the most of the existing opportunities and ensure the support necessary for a successful transition to the green port model.

4.2. A Phased Approach

The Port of Bar is the main cargo port of Montenegro and the key point of the country’s maritime connection with the Adriatic and Mediterranean region. Located in the city of Bar, this port has strategic importance due to its direct rail and road connection (see

Table 6. Connectivity with the markets of the Balkans and Central Europe [74].

Town	Road	Railway	Town	Road	Railway
Belgrade	530 km	476 km	Prishtina	551 km	651 km
Novi Sad	580 km	632 km	Szeged	759 km	797 km
Subotica	691 km	653 km	Budapest	875 km	826 km
Skopje	442 km	642 km	Bucharest	940 km	926 km

). As the only major port of Montenegro, the Port of Bar enables the reception of large ships (water depth in the port basin is up to 14 m) and offers infrastructure for transshipment of bulk, liquid, general and container cargo [73].

The structure of operators in the Port of Bar includes several entities with different domains of activity. The Port of Bar AD acts as the parent port company that manages most of the terminals and storage facilities. This company is majority-owned by the state, with a share of 78.55% [74]. Port of Adria, managed by Global Ports Holding, took over the management of container and RO-RO terminals in 2013 through the privatization process, with a strategic focus on modernizing equipment and improving efficiency [73,75,76].

Rail transport connected to the port is carried out by the company Montecargo AD, which specializes in cargo transport and is an integral part of the multimodal logistics of Montenegro [77]. Oil derivatives and energy products are stored and distributed within the port by Jugopetrol AD, a branch of the Hellenic Petroleum group, with a storage capacity of 116,000 m³ in Bar [78,79].

The Port of Bar is currently in transition towards a more sustainable and digitized business model, with the potential to become a regional “Green Hub” for Southeast Europe [80].

Figure 7 shows the general and container terminal at the Port of Bar.

Infrastructure.

Port infrastructure includes several berths, as presented and described in

Table 7. Operative quays of the Port of Bar [82].

Type	Length (m)	Water Depth (m)	Sea Level (m)
“Voluica” quay	554.4	10.7–14	3
“Old” quay	280	3.0–7.2	2.5
New petroleum berth	66	13.5	2.5
Berth 26 (pier II/pier III)	239	10.5	3
Southern quay of pier iii	136	8.1	3
Passenger terminal	332	5.9	2

.

Port infrastructure also includes electricity, water supply, sewerage and telecommunication infrastructure and port road and rail traffic networks under the operation and management of the Port of Bar [82].

The facilities of the port superstructure, which are owned by the Port of Bar [82], are in the direct function of carrying out basic port activities, as listed below.

• Enclosed port warehouses: No. 10 (area 6300 m²) and No. 13 (area 5982 m²);
• Grain silo with storage capacity of 30,000 tons;
• Cold storage—7749 m²;
• Prefabricated warehouse—1200 m²;
• Prefabricated warehouse—600 m²;
• Modular/demountable warehouse (inflatable hall)—4590.4 m²;
• Warehouses: B1—48 m², M2—216 m², M3—216 m², M4—1159 m².

The Port of Bar offers a wide range of transshipment and storage services for different types of cargo, with a special focus on its Dry Bulk Terminal. The Port of Bar is a key logistics center in the region, with a terminal for liquid cargo, RO-RO, general cargo and containers, providing clients with high-quality transshipment and storage services.

Figure 8 illustrates the cargo handling development in the Port of the Bar for the period 2022–2024 [83,84,85].

According to the requirements of the port operations it performs, the Port of Bar possesses different types of cargo handling equipment. An overview of the cargo handling equipment deployed in the Port of Bar is given in

Table A1. Cargo handling equipment in the Port of Bar.

No.	Family	Unit	Brand and Type	Year of Manufacture
1	ELECTRIC FORKLIFT 1.8 T	2	HELI electric CPD-HT2 1.8 t	2019
2	ELECTRIC FORKLIFT 2 T	4	STILL electric RX 20-20 2.0 t	2020
3	DIESEL FORKLIFTS 3 T	2	STILL RX 70-30 triplex-duga 4200 diesel 3.0 t	2012
4	DIESEL FORKLIFTS 3 T	1	STILL RX 70-30 triplex-duga 4200 diesel DPF 3.0 t	2012
5	DIESEL FORKLIFTS 3 T	2	NETLIFT FG 30t-m/GF3 triplex 4800 diesel 3.0 t	2020
6	DIESEL FORKLIFTS 3 T	2	HELI CPCD30-WS1H diesel 3.0 t	2020
7	DIESEL FORKLIFTS 3 T	3	STILL RX 70-30/600 Hybrid Drive 3.0 t	2024
8	DIESEL FORKLIFTS 3 T	1	HANGCHA CPCD 35N-RW13 diesel 3.5 t	2008
9	DIESEL FORKLIFTS 3 T	1	LINDE H35D	2008
10	DIESEL FORKLIFTS 6 T	1	STEINBOCK BOSS H60 diesel 6.0 t	2000
11	DIESEL FORKLIFTS 6 T	1	HELI CPCD60-P2 diesel 6.0 t	2020
12	DIESEL FORKLIFTS 12.5 T	1	LITOSTROJ V 12,5IH simplex 14,800 diesel 12.5 t	1987
13	DIESEL FORKLIFTS 16 T	1	KALMAR DCG160-12T 16 t	2019
14	DIESEL FORKLIFTS 25 T	1	HELI CPCD250-VZ2-12 III diesel 25 t	2020
15	42T FORKLIFT WITH SPREADER	1	LANCER BOSS G4212GPCH duplex 56,300 42 T	1998
16	REACHSTACKER 45 T	1	KALMAR DRU450-6S REACHSTACKER	2020
17	80T MOBILE CRANES	1	DEMAG AC80-1 80 T	2000
18	PORT MOBILE CRANE	1	LIEBHERR LHM550 144 T	2011
19	PORT MOBILE CRANE	1	LIEBHERR LHM420 124 T	2020
20	LOADERS	2	CATERPILLAR 950 H 3.5 m3	2008
21	LOADERS	1	CATERPILLAR 966GC 4.2 m3	2021
22	LOADERS	2	CATERPILLAR 950GC 3.5 m3	2022
23	LOADERS	1	CATERPILLAR 966GC 4.2 m3	2022
24	LOADERS	1	CATERPILLAR 216B II SKID STEER 0.4 m3	2008
25	LOADERS	1	CATERPILLAR 236D3 Skid Steer Loader	2023
26	LOADERS	2	KOMATSU WA200PZ-6 1.5 m3	2011
27	LOADERS	1	KOMATSU WA380-6 3.6 m3	2011
28	LOADERS	1	KOMATSU SK1026-5 SKID STEER 0.5 m3	2011
29	LOADERS	1	HYUNDAI HL770-9A 4.1 m3	2013
30	LOADERS	1	HYUNDAI HL730-9 1.9 m3	2024
31	MATERIAL HANDLER	1	SENNEBOGEN 825.0.1915 MATERIAL HANDLER	2013
32	MATERIAL HANDLER	1	SENNEBOGEN 825.0.2541 MATERIAL HANDLER	2018
33	MATERIAL HANDLER	1	SENNEBOGEN 825.0.2665 MATERIAL HANDLER	2020
34	MATERIAL HANDLER	1	SENNEBOGEN 835.0.3397 MATE RIAL HANDLER	2024
35	TRACTOR TRUCK	3	IVECO STRALIS 460 ECO	2012
36	TRACTOR TRUCK	2	MERCEDES ACTROS 1844 LS 4X2	2008
37	TRACTOR TRUCK	1	MERCEDES ACTROS 1850 LS 4X2	2003
38	TRACTOR TRUCK	2	MAN TGS 18 400	2015
39	TRACTOR TRUCK	2	MERCEDES ACTROS 1844 LS 4X2	2008
40	TRUCK SWEEPER	1	MERCEDES BENZ ATEGO 1318 LKO FAUN VIAJET	2008

in Appendix A [86].

Table A1 in Appendix A also provides insight into more detailed information (e.g., number and type of devices). In the previous period, such data were marked as “confidential”, i.e., the result of company and operational secrets.

To meet its daily operational needs, the Port of Bar maintains a small fleet of terminal vehicles, which are listed in

Table A2. Terminal vehicles.

No.	Family	Unit	Year of Manufacture
1	PASSENGER VEHICLE	1	2012
2	PASSENGER VEHICLE	2	2012
3	PASSENGER VEHICLE	1	-
4	PASSENGER VEHICLE	1	2010
5	PASSENGER VEHICLE	1	-
6	PASSENGER VEHICLE	1	2007
7	SHUTTLE BUS	1	2023

in Appendix A [86].

4.2.1. First Pilot Phase 2026–2030

The first phase of the transition of the Port of Bar towards a “green” business model lays the foundation for the future development of sustainable and digitally enhanced port operations. This phase is planned to last from 2026 to 2030 and to include key changes that will enable the reduction in the negative impact on the environment, while simultaneously enhancing the port’s operational efficiency.

Through a comprehensive approach that includes transitioning to clean energy, upgrading infrastructure, and introducing digital innovations, the Port of Bar strives to build a stable foundation for a long-term transition. Significant importance will be assigned to emissions control, energy optimization and process improvement through digital tools.

Key Objectives

The main goals of this phase are clearly defined and measurable, which enables transparent monitoring of achievements and timely decision-making.

Within this phase, the following key objectives are defined.

• Boosting the share of renewable energy sources within the port’s total consumption;
• Replacing part of the current diesel-operated equipment with electric versions;
• Reduction in CO₂ emissions compared to the base year of 2024;
• Upgrading the Port Community System (PCS) and advancing digital logistics capabilities.

Measures

In order to achieve the goals set within the first Pilot phase of the transition, a set of priority activities related to four key areas is defined: energy, equipment, infrastructure and digitization. Each of these activities is assigned a clearly defined goal, ensuring that progress can be systematically tracked and evaluated in a transparent way. The planned measures represent practical steps towards improving energy efficiency, reducing emissions and digital modernization of port processes. In line with the structure of this document, the following section presents activities categorized by area.

• Integration of Electric Equipment in Port Operations

To deliver the expected results, port equipment must undergo electrification.

As already shown in Table A1 (Appendix A Table A1: Cargo handling equipment Port of Bar), the Port of Bar has 24 forklifts, 18 of which are diesel-powered. Also, for the needs of port operations, the Port of Bar has 14 diesel-powered loaders. As part of the Pilot phase, the proposal is to carry out electrification, i.e., the purchase of eight new forklifts (which represents 44% of the total number of diesel-powered forklifts) and eight loaders (which represents 57% of the total number of diesel-powered loaders). During 2024, the Port of Bar spent a total of EUR 708,528.72 on fuel and lubricants [85].

After surveying the European market for electric material-handling equipment suitable for port operations, two models stood out as the best fit for the needs of the Port of Bar. The selection was based on key criteria such as performance, reliability, energy efficiency, delivery times and cost-effectiveness.

For heavier tasks like container and bulk cargo handling, Hyster’s J10–18XD electric forklifts offer robust construction, lithium-ion battery systems, and proven durability in demanding port environments [87,88]. These forklifts are widely available across Europe and allow rapid deployment.

For lighter indoor and yard operations, BYD’s ECB30D electric forklifts are ideal due to their low maintenance requirements, long battery life, and efficient charging. Their affordability and strong operational track record make them a cost-effective choice for day-to-day logistics [88,89].

The recommended models, described in

Table 8. Recommended electric forklifts for the Port of Bar.

Type	Model	Quantity	Capacity	Battery Type	Charging Time	Unit Price (EUR)	Source
Heavy-duty Forklift	Hyster J10–18XD	3	10–18 tons	Lithium ion	~2 h	115,000	[87,88]
	BYD ECB30D
Medium-duty Forklift	Hyster J10–18XD	5	3 tons	Lithium iron phosphate	~2 h	38,000	[88,89]

, align with the port’s current equipment replacement plan and offer a balanced combination of quality and value.

Following an assessment of electric wheel loaders on the European market, the Volvo L25 Electric stood out as the most practical and cost-efficient choice for the Port of Bar. It combines energy efficiency, fast charging, and proven performance in demanding conditions.

Equipped with a 39 kWh lithium-ion battery, it offers 6–8 h of active use and can fully recharge in about two hours using a DC fast charger [90]. Its compact size makes it ideal for daily port tasks such as warehouse handling and yard operations.

The recommended model, described in

Table 9. Recommended Electric Loaders for the Port of Bar.

Type	Model	Quantity	Bucket Capacity	Battery Type	Charging Time	Unit Price (EUR)	Source
Compact e-loader	Volvo L25 Electric	8	1.17 m3	Lithium ion	~2 h	~125,000	[90,91]

, aligns with the port’s current equipment replacement plan and offers a balanced combination of quality and value [90,91].

This step represents the biggest financial challenge within the Pilot phase. Part of the required funds can come from the Port of Bar’s own budget (using planned allocations for electricity, fuel and lubricants) [82], while most of the investment can be covered through state subsidies [71] and EU development and “green” funding.

• Enhancing the Port’s Renewable Energy Share

By examining the current situation, it was determined that the energy infrastructure of the port is based on one system, and we are not able to allocate energy consumption to specific energy consumer groups.

Documentation indicates that in 2024, the Port of Bar’s electricity expenses totaled EUR 608,785.79, which, under the prevailing tariffs, equates to roughly 3.7 GWh (authors’ calculation based on energy cost and assumed to be EUR 0.13/kWh, [21]).

In order to move towards a more sustainable and energy-efficient business, the Port of Bar has the opportunity to join the national project Solari 500+, which is implemented by EPCG in cooperation with the eco-fund [71,92]. This program enables companies and private individuals to access its services as customers, i.e., producers of electricity, by installing photovoltaic systems of up to 30 kW power on commercial buildings. Users of the system can meet their own energy needs through solar production, while energy surpluses and deficits are exchanged through the distribution network and financially balanced on an annual basis.

Since EPCG provides technical and production data only up to a 10 kW system in publicly available documents [93], this capacity has been used as a reference in the analysis of solar power needs for the Port of Bar. Based on these data, a 10 kW photovoltaic system installed in the south of Montenegro produces an average of 16,080 kWh per year [93]. Using this data as a basis, it was estimated that to cover the annual production of 3 GWh, the Port of Bar would have to install around 187 systems of 10 kW each, which is a total of 1.87 MW of installed power and requires approximately 13,000 m² of roof area.

The Port of Bar currently has significant capacities for the installation of photovoltaic systems—including existing closed storage facilities—as well as two new warehouses under construction, with a total area of 7500 m² and 6000 m² [94]. Taking the existing halls and assembly facilities into account, it is clear that the total roof area is large enough to support a system of the needed capacity, creating a solid basis for producing renewable energy on site.

Considering the character and location of its facilities, the Port of Bar meets most of the criteria defined by the Solari 500+ project, including three-phase connections, high annual consumption, technical conditions of the roof and regular settlement of obligations. An additional convenience of the program is reflected in a subsidy of 20% of the total investment by the eco-fund, while the remaining amount is repaid in monthly instalments approximately equal to previous consumption bills, during a maximum of ten years [92]. During an interview with representatives of EPCG and Solar Gradnja Company (Nikšić, Montenegro), it was confirmed that the cost of installing a 10 kW system is EUR 6988.95.

An overview of solar energy requirements and investment plan for the Port of Bar is shown in

Table 10. Overview of solar energy requirements and investment plan for the Port of Bar.

Parameter	Value	Source
Annual electricity cost (2024)	EUR 608,785.79	[85]
Reference system capacity (per unit)	10 kW	[93]
Average annual production (per 10 kW system)	16,080 kWh	[93]
Required total annual production	3,000,000 kWh (3 GWh)	Author calculation
Number of 10 kW systems required	187 units	Author calculation
Total installed capacity	1.87 MW	Author calculation
Estimated required roof area	~13,000 m2	[82,94].
Unit system cost (10 kW) Eko fond subsidy (20%) included	EUR 6988.95	Unpublished data, EPCG & Solar Gradnja interview, 2025
Total investment Eco-fund subsidy (20%) included	EUR 1,306,938.65	Author calculation
Payment period	Up to 10 years	[92]

.

A feasibility study was prepared to evaluate the profitability of investing in solar photovoltaic systems for the Port of Bar, taking into account the main technical and financial factors. The analysis aligns with global decarbonisation pathways outlined in the IEA’s World Energy Outlook 2022, which identifies distributed solar PV on industrial and port infrastructure as a key near-term lever for emissions reduction in hard-to-abate sectors [95]. It also incorporates best practices for energy efficiency in motor-driven systems, as recommended by the U.S. Department of Energy for reducing baseline demand and maximising self-consumption of renewable generation [96].

The analysis took into account the level of electricity consumption for 2024, the planned expansion of the fleet with electric machines, as well as data on production capacity and installation costs obtained from EPCG and other reliable sources. Based on the available information, a projection of energy coverage, total investment costs, potential annual savings and expected investment return period was made. The key results are shown in

Table 11. Feasibility study of solar investment for the Port of Bar.

Parameter	Value	Source
Annual electricity consumption (2024)	~3.7 GWh	[85]
Estimated additional consumption (New e-equipment)	~0.3 GWh	[93]
Total projected consumption	~4.0 GWh	[93]
Annual electricity cost (2024)	EUR 608,785.79	Author calculation
Solar capacity to be installed	187 units × 10 kW	Author calculation
Total energy produced by solar system	~3.0 GWh/year	Author calculation
Estimated coverage with solar (post-electrification)	~75%	[82,94]
Investment cost (with subsidy included)	EUR 1,306,938.65	Author calculation, based on unpublished data (EPCG & Solar Gradnja interview, 2025)
Estimated annual savings (at €0.13/kWh)	~ EUR 390,000	Author calculation
Payback period	~3.35 years	[92]
Ownership & energy independence after payback	100% of solar-produced energy

, which can serve as a foundation for further planning and concretization of energy transition steps.

• Reduction of CO₂ emissions

Given that the Port of Bar consumed around 3.7 GWh in 2024 (authors’ calculation based on energy cost and assumed to be EUR 0.13/kWh, [21]) and that after the aforementioned electrification of the port’s equipment, electricity consumption will increase by approximately 0.3 GWh per year (Table 11: Feasibility Study of Solar Investment for the Port of Bar), the analysis leads to the following projection of around 4.0 GWh of annual electricity consumption.

For the calculation of CO₂ emissions, a formula was used that is consistent with international standards defined by the IPCC and the GHG Protocol [71,97].

CO₂ emissions (t) = E_consumption × EF

where

-

E_consumption is the annual electricity consumption in megawatt-hours (MWh);

-

EF is the emission factor in tons of CO₂ equivalent per MWh (t CO₂e/MWh).

Taking the average emission factor from the network of 0.405 tCO₂e/MWh [98], the projected annual consumption of electricity will result in the emission of about 1620 tons of CO₂.

CO₂_before = 4000 MWh × 0.405 t CO₂e/MWh = 1620 t CO₂e/year

After the installation of solar panels, the projected annual CO₂ emission will amount to:

CO₂_after = 1000 MWh × 0.405 t CO₂e/MWh = 405 t CO₂e/year

The planned installation of solar panels with a total power of 1.87 MW, which will annually produce around 3.0 GWh of green energy, enables the reduction in consumption from the network to only 1.0 GWh. This would reduce emissions to 405 tCO₂e per year, which represents a net reduction of about 1215 tCO₂e per year.

ΔCO₂ = CO₂_before − CO₂_after = 1620 − 405 = 1215 t CO₂e/year

The replacement of eight diesel forklifts and eight diesel loaders with electric alternatives is projected to reduce annual CO₂ emissions by approximately 443 tons. The calculation is based on standard average consumption—7 L/h for forklifts [99] and 18.9 l/h as the maximum consumption of diesel loaders [90], although in practice 8 L/h is used for loaders with a real working mode, where both types of equipment work for about 1500 h per year, with an emission factor of 2.64 kg CO₂/L of diesel [100].

CO₂ emissions (kg) = N × H × C × EF

where

• N = number of machines;
• H = annual operating hours per machine;
• C = average fuel consumption in liters per hour (L/h);
• EF = emission factor for diesel fuel (kg CO₂/L).

Diesel Forklifts

CO₂_forklifts = 8 × 1500 × 7 × 2.64 = 221,760 kg CO₂/year ≈ 222 t CO₂/year

Diesel Loaders

CO₂_loaders = 8 × 1500 × 8 × 2.64 = 253,440 kg CO₂/year ≈ 253 t CO₂/year

Annual Emissions Reduction

Total Reduction = 222 + 253 = 475 t CO₂/year

The total annual emissions reduction of about 1690 tons of CO₂e represents an extremely important step towards reducing the port’s carbon footprint. To present this amount in a more comprehensible way, it can be compared to natural processes: this amount of carbon dioxide corresponds to the emissions that would be absorbed annually by about 28,644 trees [100]. The estimate is based on the average value that one tree absorbs 0.059 metric tons of CO₂ per year, according to data from the US Environmental Protection Agency. Such comparisons highlight the significance of decarbonization in the port sector and facilitate a better understanding among the general public through intuitive representation.

• Port Community System (PCS)

The Port of Bar has implemented a Port Community System (PSC) that serves for truck announcements, electronic ship announcements and requests for mooring/unmooring and electronic delivery of dispositions and daily orders [101].

The PCS in the Port of Bar has a good foundation, but the modernization should go towards full digitization of processes, interoperability with other systems, user mobility and environmental optimization. Also, the modern PCS must be a proactive decision-making tool, not just a passive platform for information exchange.

In this paper, three steps towards the modernization of the PCS are listed as part of the first Pilot phase.

I.

Integration with Customs and Logistics Systems in Real Time

Seamless integration of the PCS with systems used by Customs Administration, Port of Adria, Montecargo, and other key logistics operators enables real-time data exchange and eliminates the need for manual input and paperwork. Such interoperability is already successfully implemented in ports like Hamburg (DAKOSY) and Rotterdam (PORTBASE), where unified data flows have significantly reduced cargo processing times [37].

Action: Develop a standardized API/EDI interface to ensure two-way, real-time communication between the PCS and external logistics and government platforms.

By enabling real-time synchronization of vessel and cargo information, the integrated PCS will also support dynamic berth and terminal scheduling, reducing vessel waiting times and fuel burn during anchorage. This direct link between digital connectivity and port operations will generate measurable reductions in CO₂ emissions while improving the overall flow of goods and energy use efficiency across the logistics chain.

II.

Implementation of Automated Resource Planning and Predictive Analytics

The use of artificial intelligence (AI) for forecasting congestion, managing terminal capacities and optimizing resource allocation leads to measurable operational improvements. Ports such as Koper and Busan already rely on these technologies to reduce delays and lower handling costs [16,35].

Action: Introduce a smart module within the PCS that collects and analyzes data from ship, truck and cargo announcements and generates automated resource scheduling based on predictive modeling.

Such predictive analytics will enable the port to anticipate congestion scenarios and dynamically reallocate resources, minimizing idle equipment and energy waste. By shortening operational cycles and improving berth turnover, this digital module will contribute to lower vessel idling emissions, reduced equipment run times and improved energy efficiency at the terminal level.

III.

Adding a Green Management and ESG Reporting Module

By integrating tools to monitor CO₂ emissions, electricity consumption, and the use of electric port equipment, the port can track its carbon footprint and align with EU Green Deal sustainability targets. The Port of Koper is already applying similar tools through its PCS to monitor environmental performance and energy efficiency [16].

Action: Develop a real-time dashboard within the PCS to monitor emissions and energy usage, with automated ESG reports for internal decision-makers and external stakeholders.

The inclusion of a Green Management and ESG module will allow for real-time environmental monitoring across the port complex. Through continuous tracking of energy consumption, equipment utilization and renewable energy input, the upgraded PCS will enable data-driven energy management and support adaptive decision-making. This will allow the Port of Bar to optimize electricity distribution, prioritize low-emission equipment and measure sustainability performance indicators, dynamically transforming digitalization into a concrete driver of environmental improvement.

Table 12. PCS modernization.

Parameter	Value
Integration	Faster cargo processing, elimination of duplicate data, better control
Predictive Analytics	Higher efficiency, fewer delays, reduced operational costs
Green Module	ESG alignment, improved reputation, better access to green funding

lists the key benefits after the implementation of the abovementioned steps, with the aim of modernizing the existing PCS System.

Economic Feasibility and Cost–Benefit Analysis of Phase I (2026–2030)

This section presents and analyzes the comprehensive economic assessment of Phase I, which includes capital expenditures (CAPEX), operational savings (OPEX), proceeds from asset sales and return on investment.

• Capital Expenditure and Asset Monetization

The indicative market price of the new electrical operating equipment is estimated at EUR 1,535,000. With a 20% grant from the Eco-Fund of Montenegro (in the amount of EUR 307,000), net expenses are reduced to EUR 1,228,000.

In parallel, the installation of a photovoltaic (PV) system with a capacity of 1.87 MW in the amount of EUR 1,306,939 is planned, which already includes a 20% subsidy from the eco-fund [Unpublished data, interview EPCG & Solar Gradnja, 2025].

The combined net investment therefore amounts to EUR 2,534,939.

The Port of Bar will initially allocate an amount of around EUR 258,000 from its operating budget for 2026, planned to cover advance payments for new equipment. The plan is for this amount to be fully recouped by the resale of 16 obsolete diesel units (manufactured between 1987 and 2013), with an estimated current market value of EUR 258,000. In this regard, the port’s direct financial contribution is effectively limited to zero, while the remaining EUR 2,276,939 is expected to be financed through EU pre-accession aid instruments (e.g., IPA III, CEF).

Accordingly, the indicative financial structure assumes that, during this phase, approximately 8% of the total investment will be covered by the Port of Bar, 18% by the Eco-Fund of Montenegro, and 74% through EU funding instruments.

• Operational Expenditure Savings

By replacing the aforementioned diesel units, which are characterized by both high consumption and high maintenance costs directly related to the number of working hours achieved so far, it is projected that 75.8% of the port’s total expenditure on fuel and lubricants will be eliminated. Considering the 2024 figure of EUR 708,529 [85], this translates into annual operating cost savings of EUR 537,000, which includes EUR 507,000 in fuel costs and EUR 30,000 in lubricants. These estimates are based on manufacturer-specified fuel consumption rates [96], were validated through direct consultation with port operating personnel and are aligned with industry benchmarks for port machinery maintenance costs [99].

With the installation of the photovoltaic system, it is predicted that 3.0 GWh/year will be generated, which will enable covering 75% of the port’s demand for electricity after electrification [82,93,94]. With a conservative grid tariff of EUR 0.13/kWh [93], this yields an additional projected annual saving of EUR 390,000.

It is estimated that the total annual savings will amount to EUR 927,000.

• Return on Investment

The investment return was calculated on the basis of the port’s own financial contribution, because EU grants and national grants represent irreversible support. Since the EUR 258,000 budgeted for 2026 is fully offset by the resale of equipment in the same year, the net cash outflow is zero, and any subsequent savings represent a net surplus.

Given that Phase I lasts four years (2026–2030), the port will generate a net positive cash flow throughout the phase, resulting in a cumulative surplus of approximately EUR 3.7 million by 2030. This surplus can be reinvested in Phase II initiatives or other measures to improve sustainability.

After the initial asset turnover, the port will additionally benefit from the following:

• Almost zero fuel costs for replaced equipment;
• Significantly reduced electricity bills;
• Full ownership of solar assets with a remaining useful life of 20+ years [92].

The financial model created in this way, which uses property monetization, national grants and EU co-financing, shows that the green transition can be implemented with a minimal fiscal burden on the port while at the same time achieving significant long-term economic and environmental returns.

Critical Risks and Mitigation Strategies

As discussed and elaborated in earlier chapters, the first phase of the transition focuses on the introduction of solar photovoltaic systems, the replacement of some diesel handling equipment with electric alternatives and the establishment of basic digital and monitoring infrastructure.

However, several operational and institutional risks could delay or hinder the expected results.

The main challenge is the time frame that will be required for the preparation and execution of feasibility studies, environmental impact assessment and analysis of network connection before installation. Preparation of project documentation, submission of applications and provision of financial support through EU development funds can also be causes of certain delays.

In addition, the procurement and delivery time of specialized equipment is subject to global supply chain dependencies and possible delivery bottlenecks. All of this can be additionally threatened by the diversification of suppliers and also by geopolitical fluctuations that greatly affect the transport and logistics sector.

Institutional risks are reflected in the availability of adequately trained personnel for technical maintenance and operation of the system, and in this part a targeted initiative for training and building professional capacity is needed so that the Port of Bar does not end up in a situation where new integrated systems face operational inefficiency or increased downtime.

In order to mitigate the abovementioned risks, the Port of Bar should establish an expert working group for the early preparation and monitoring of projects, which will be responsible for the coordination of technical studies, tender procedures and training activities. Furthermore, the conclusion of long-term framework agreements with certified EU equipment suppliers, combined with a phased procurement model, would reduce exposure to market volatility. Partnerships with regional universities and vocational centers could also provide a skilled workforce to support the operation and maintenance of the system.

4.2.2. The Second, Ambitious Phase 2030–2038

The second, so-called ambitious phase of the Port of Bar’s transition represents at the same time the biggest financial and technological challenge for port management. The implementation of the measures listed below and the achievement of the set goals would ensure complete decarbonization and modernization of the infrastructure [25,102]. The Port of Bar would assert itself as a regional “Green Hub” and at the same time could serve as a good example of the transition of small and medium-sized ports [103].

Key Objectives

In order to enable transparent monitoring and timely decision-making, the main goals of this phase must be clearly defined and measurable.

Within this phase, the following key objectives are defined:

• Achieve complete electrification of port equipment;
• Provide full OPS coverage for ships at berth;
• Ensure that renewable energy sources fully supply the port’s energy demand;
• Achieve full decarbonization of port operations (net-zero port).

Measures

In order to achieve the key objectives within this phase of transition, a set of activities related to three key areas is defined: equipment, infrastructure and energy. Each of these activities has a clearly defined goal that allows progress to be monitored and measured in a transparent manner. These measures are aimed at the Port of Bar becoming a fully decarbonized port and achieving net-zero status, through reducing emissions and improving the energy efficiency of all port operations. A detailed list of planned measures by area can be found below.

• Integration of Electric Equipment in Port Operations

To reach its goal of becoming a net-zero port by the end of the transition period, the Port of Bar needs to fully electrify its cargo handling equipment.

As already mentioned, during the first Pilot phase, electrification will begin with the replacement of eight diesel forklifts with eight electric ones and the replacement of eight diesel loaders with eight electric loaders. Also, the Port of Bar signed a contract with the renowned company “Liebherr-International AG” on the purchase of a new port mobile crane LHM 550, whose delivery is expected in the third quarter of 2025 [104]. During an interview with a Port of Bar representative, we were informed that the crane had not been ordered with a shore power retrofit kit [105].

Taking into account the equipment that the Port of Bar currently has, as already shown in Table A1 (Appendix A Table A1: Cargo handling equipment Port of Bar), the electrification of equipment as part of the Pilot phase (Table 8 and Table 9) and the order of a new mobile crane LHM 550 [104], as part of this phase, it is proposed to carry out software upgrades and install shore power retrofit kits on the mobile cranes, as well as to continue electrification through the purchase of new equipment and vehicle fleet renewal.

Based on the current state of the market, a preliminary list of equipment was made, taking into account the price–quality ratio, as well as previous work experience. The recommended equipment is shown in

Table 13. Recommended electric equipment for the Port of Bar.

Type	Model	Quantity	Capacity	Battery Type	Charging Time	Unit Price (EUR)	Source
Heavy-duty Forklift	Hyster J10–18XD	3	10–18 tons	Lithium-ion	~2 h	115,000	[87,88]
Medium-duty Forklift	BYD ECB30D	7	3 tons	Lithium iron phosphate	~2 h	38,000	[88,89]
Compact e-loader	Volvo L25 Electric	6	1.17 m3	Lithium-ion	~2 h	~125,000	[90,91]
Reachstacker	Kalmar Electric Reachstacker	1	45 t	Lithium-ion	~6 h	~360,000	[106]
Material Handler	Sennebogen 825 E	4	28–30.4 t	Li-ion battery + dual power	~4–6 h	300,000–350,000	[107,108,109]

and

Table 14. Recommended tractor truck and tractor sweeper for the Port of Bar.

Type	Model	Quantity	GVWR	Battery Type	Charging Time	Unit Price (EUR)	Source
Volvo Truck	VNR Electric	10	37,200 kg	100% Battery Electric	90 min DC fast charge	366,500–412,300	[110,111,112,113]
Dulevo International	Dulevo D.Zero2 Electric	1	~25,200 m2/h	Li-ion battery	5.5 h	281,800	[114,115]

. This overview gives a rough picture of possible solutions. However, the final selection will be made in due course, based on available offers, pricing, availability and any new models that can become available.

Sources of data on specifications and cost estimates for the Sennebogen 825 E Electro Battery were taken from the manufacturer’s official website and compared to the market prices of used diesel versions available on Mascus, applying an additional cost factor (30%) for the battery drive based on the Sennebogen Green Efficiency study [107,108,109].

Considering the year of manufacture, condition and large number of working hours, it is technically not achievable to upgrade the existing two mobile cranes (Demag AC80 1 80 t and Liebherr LHM550 144 t—see Appendix A Table A1: Cargo handling equipment Port of Bar) to meet current environmental standards. Moreover, as the Port of Bar has already placed an order for a new mobile crane, it is advisable to put these two cranes on the market for sale.

If in practice it turns out that the existing crane (Liebherr LHM420, 124 t—see Appendix A Table A1: Cargo handling equipment Port of Bar and the new one that was ordered are still not sufficient for all the port’s needs [110], it is suggested that the Port of Bar, according to the actual situation, consider the purchase of another mobile crane with pre-installed software and the possibility of connecting to shore power.

Despite the fact that there is no publicly available, official price for the shore power retrofit kit and software upgrade for existing Liebherr LHM models, indicative values are derived based on analyzes of similar modernization projects in European ports, technical specifications for new models and market assessments by specialized contractors. The specific values in the

Table 15. Shore power retrofit cost estimates—Liebherr LHM.

Year	Model	Retrofit Kit (EUR)	Software and Integration (EUR)	Total Upgrade Cost (EUR)	Source
2020	LHM 420 (124 t)	1,000,000–1,300,000	200,000–300,000	1,200,000–1,600,000	[20,105]
2025	LHM 550 (144 t)	600,000–900,000	150,000–200,000	750,000–1,100,000	[105,116]

represent the estimated range of costs, while for the exact price it is necessary to request an official offer directly from the manufacturer or an authorized service [20,105,116].

Regarding terminal vehicles, and in order to complete the electrification of port equipment, the following model is proposed in

Table 16. Recommended electrical vehicle for the Port of Bar.

Model	Price (EUR)	Battery (kWh)	Range	Power (kW)	Quantity	Source
Dacia Spring	~20,000–22,000	26.8	230 km	33 kw	6	[117]

.

In order to provide the necessary financial fund, part of the necessary financial resources can be provided from the budget of the Port of Bar (from the planned funds for electricity, fuel and lubricant) and from the funds obtained from the sale of existing equipment, while most of the investment can be covered through state subsidies (ECO Fund) and EU development and “green” funding.

• Onshore Power Supply System

The introduction of the Onshore Power Supply (OPS) system represents one of the key steps towards the decarbonization and modernization of the Port of Bar. By applying the OPS solution, ships will be able to use electricity from the land instead of ship’s auxiliary engines, which significantly reduces emissions of harmful gases in the port area. This project directly contributes to meeting European environmental standards and strengthening the port’s competitiveness.

According to IAPH, ESPO and UNCTAD guidelines, the costs of implementing Onshore Power Supply (OPS) systems in European ports range from an average of EUR 2–4 million per MW of installed power, including shore power connections, substations, frequency converters, monitoring software and all necessary construction works [118,119,120].

Similarly, in the UNCTAD Review of Maritime Transport 2023, it is pointed out that investments in shore power are around EUR 2–4 million/MW, with variations depending on the type of ship, location and national regulatory requirements [120].

For the Port of Bar, where the OPS is planned to include five berths for bulk carriers, general cargo and passenger ships, the indicative power of 10–12 MW gives a total investment estimate of between EUR 20 and 30 million, as described in

Table 17. Estimated investment for OPS system in Port of Bar.

Item	Description	Estimated Cost (€)	Source
Number of berths covered by OPS	Bulk carriers, general cargo and passenger ships	5 berths (estimate)	[118,119]
Average cost per MW	Includes shore connection, substations, converters, civil works	EUR 2–4 million per MW	[118,119,120]
Estimated capacity per berth	Bulk/general cargo: ~2 MW; passenger: 3–4 MW → avg. 2–2.5 MW per berth	~10–12 MW total	[118,119]
Civil works & infrastructure	Cable trenches, ducting, network upgrades, SCADA, EMS software (included)	Included in MW cost	[118,120]
Total estimated investment	Complete OPS coverage for Port of Bar (5 berths)	EUR 20–30 million	[118,119,120]

. This aligns with average investment levels in comparable EU ports [118,119,120].

One of the relevant examples for planning the OPS system is the Port of Koper, which in its decarbonization strategy has foreseen the implementation of shore power solutions for containers and general cargo terminals.

The estimated investment for the installation of OPS infrastructure in Koper is approximately EUR 20–25 million, with the aim of covering key berths until 2030 [17,119].

This project is implemented in phases, with the support of EU funds and national incentives, as well as through the technical guidelines recommended by the European Sea Ports Organization (ESPO) for the “green” transition of ports [119,121].

To recover the invested funds, the Port of Bar needs to follow proven practices from European ports that have successfully carried out similar projects. The example of the Port of Gothenburg shows that by charging shippers for shore power services, it is possible to recover the investment in the OPS system in less than seven years while simultaneously reducing local pollution and allying with European environmental standards [19,119].

• Enhancing the Port’s Renewable Energy Share

The estimate of annual electricity consumption for the new electrical port equipment in the Port of Bar was made according to the standard methodology recommended by the U.S. EPA [122], and it is also used by leading manufacturers of work machinery.

For each type of machine, the following basic formula was applied:

Annual consumption (kWh) = Machine power (kW/h) × Number of effective operating hours per year × Number of units

For working hours, real averages of utilization of similar equipment in European ports and recommendations of manufacturers were taken.

• Mobile cranes work about 2000 h a year, which covers the transshipment season and planned downtimes due to service or weather conditions [123];
• Material handler machines and reachstackers are used intensively, but not continuously, so an average of about 1500 to 2000 h per year was applied [107,109,124];
• For forklifts and compact loaders, 1000–1500 working hours per unit are foreseen, in line with average port shifts [87,89];
• For electric trucks an average annual operation of 30,000 km is assumed, which corresponds to internal transport and local deliveries [110,111];
• For terminal vehicles, we used typical data for city fleet cars, about 10,000 km per year [117];
• Specialized equipment like the Dulevo D.Zero² sweeper is planned for around 1500 working hours per year, which covers the daily cleaning of operating surfaces [114].

All hourly consumption values were taken from the technical specifications and brochures of the manufacturer, and realistic, moderate values were used for the calculation in order to make the assessment as reliable as possible. In total, it is estimated that new electrical equipment would consume around 1.2 GWh per year.

In the first phase of planning, the current situation was also taken into account, so together with the existing consumption from 2024 [85], it was estimated that the total annual consumption of the Port of Bar could reach about 4 GWh. Thanks to the solar panels already installed as part of Phase I, the port now covers around 3 GWh of its needs from renewable sources, significantly reducing its dependence on the grid (see Table 10: Overview of Solar Energy Requirements and Investment plan for the Port of Bar).

In order to assess the profitability of investing in solar photovoltaic systems within Phase II, a detailed feasibility study was prepared so that includes all key technical and financial aspects. The analysis considered the projected level of electricity consumption that is not covered by the existing solar panels from Phase I, the planned expansion of the fleet with electric machines, as well as data on production capacities and installation costs obtained from EPCG and other reliable sources. On the basis of these data, a projection of the port’s energy self-sustainability, total investment costs, possible annual savings and the expected investment return period was made. An overview of the collected data is provided in

Table 18. Solar PV feasibility—Phase II (Port of Bar).

Parameter	Value	Source
Annual electricity consumption not covered by Phase I solar	~1.0 GWh	Authors’ calculation (2025)
Estimated additional consumption (new e-equipment)	~1.2 GWh	[122]
Total projected consumption (Phase II)	~2.2 GWh	Combined estimation
Planned additional solar capacity to be installed	~3.0 GWh/year	EPCG, 2025—New project outline; Solari 500+ program expansion
Total energy produced by new solar system	~3.0 GWh/year	[93]
Estimated coverage with additional solar (Phase II)	~100% (including reserve)	Authors’ calculation
Investment cost (with subsidy included)	EUR 1,306,938.65	Author calculation, based on unpublished data (EPCG and Solar Gradnja interview data, 2025)
Estimated annual savings (at €0.13/kWh)	~€286,000	Authors’ calculation
Payback period	~4–5 years (estimate)	Authors’ calculation
Ownership and energy independence after payback	100% of additional solar-produced energy	[92]

.

These data will be finally revised once the choice of equipment is made, based on its real technical characteristics and the parameters that will be monitored under the monitoring and evaluation plan. If there is any extra demand for energy, the plan is to add more solar capacity so that the Port of Bar could stay energy self-sufficient in the long run.

• Net-Zero Port

After fully electrifying its equipment, introducing an Onshore Power Supply (OPS) system, and maximizing the use of renewable energy through solar photovoltaic panels, the Port of Bar will have a solid and realistic basis to position itself as a net-zero emissions port—fully aligned with the European Union’s goals for decarbonizing the maritime and transport sector [118,119,120]. By electrifying port machinery and internal logistics, the Port of Bar will significantly reduce emissions of CO₂ and other polluting gases compared to traditional diesel fleets [95,122].

The installation of the OPS system allows the ships to use electricity from the land instead of the ship’s auxiliary engines, which additionally eliminates the emissions of harmful gases and particles directly in the water area and the urban area of the port [118,119]. This not only improves air quality and working conditions for port workers, but also contributes to meeting the justifiably increasingly strict European environmental standards and regulatory requirements within the TEN T network [125,126].

The installation of solar panels during Phases I and II will enable the Port of Bar to cover its energy needs entirely with renewable sources, setting it on a path toward long-term energy self-sufficiency. According to the recommendations of the European Sea Ports Organization (ESPO) and international examples of good practice, the combination of the OPS system and investment in renewable sources is one of the most effective models for reducing emissions and achieving climate neutrality in ports [119,120,126].

Examples like the Port of Gothenburg prove this, where a similar concept enabled not only a quick return on investment but also a visible reduction of local pollution, which simultaneously improves the port’s competitiveness and sustainability [19,119].

All these measures together directly contribute to environmental protection and reducing the impact of harmful climate changes, whereby the Port of Bar confirms in practice that it follows the key guidelines and recommendations of UNCTAD, IEA, IMO and the European Commission for the transition of the global maritime sector towards climate neutrality [95,120,125,127].

Economic Feasibility and Cost–Benefit Analysis of Phase II (2030–2038)

This section presents the economic assessment and analysis during Phase II of the Port of Bar Green Transition Plan. The analysis includes projected capital expenditures (CAPEX), operational savings (OPEX), asset monetization and return on investment, while acknowledging the inherent uncertainties related to future equipment prices, electricity tariffs, vessel call volume and technology availability. The financial model is designed to be dynamic, with actual performance monitored through the port’s digital monitoring and evaluation (M&E) system to enable adaptive management and timely recalibration of targets [14,40,128].

• Capital expenditure and asset monetization

The estimated net investment required for Phase II is estimated at EUR 30.1 million, which includes:

• EUR 20.0 million indicative investment for infrastructure for electricity supply on land (OPS), after a 20% grant from the Montenegrin Eco-Fund;
• EUR 8.3 million indicative investment for the purchase of new electric mobile equipment and crane modifications, after a 20% subsidy from the Eco-Fund at a market price of EUR 10.4 million;
• EUR 1.3 million for an additional 3.0 GWh/year of the photovoltaic system (the subsidy is already included in the offered price);
• EUR 0.5 million to upgrade the Port Common System (PCS) to enable real-time monitoring.

This expenditure will be partially offset by the sale of the remaining obsolete diesel equipment, with an estimated resale value of EUR 2.24 million. Crucially, the port will also take advantage of the cumulative surplus generated during Phase I, which amounts to approximately EUR 3.7 million by the end of 2030.

Accordingly, the projected own financial contribution of the Port of Bar for Phase II amounts to a total of EUR 5.94 million (EUR 3.7 million + EUR 2.24 million). It is expected that the remaining EUR 24.16 million will be financed through EU pre-accession aid instruments (e.g., IPA III, CEF).

Accordingly, the indicative financial structure assumes that, during this phase, approximately 16% of the total investment will be covered by the Port of Bar, 20% by the Eco-Fund of Montenegro, and 64% through EU funding instruments.

• Operational Expenditure Savings

It is envisaged that Phase II will end with the transition of the port to full electrification and integration of renewable energy sources, which will bring three streams of financial benefits.

• Fuel and lubricant savings of around EUR 171,529 euros [85].
• The expanded solar capacity fully covers the port’s projected base demand generating annual grid savings of EUR 286,000 at a reference tariff of EUR 0.13/kWh [93].
• With 0.8 GWh/year of excess solar production and additional energy from the grid, the OPS system is expected to serve vessels at a competitive tariff of EUR 0.175/kWh (including VAT), which brings an annual revenue of approximately EUR 140,000 in a moderate berth utilization scenario of 40%.

The total annual net benefit is therefore estimated at EUR 597,529.

• Return on investment

The investment return was calculated on the basis of the port’s own financial contribution, because EU grants and national grants represent irreversible support. With a net expenditure of EUR 5.94 million, the annual benefit of EUR 597,529 implies a payback period of 9.9 years.

Taking into account the technical and organizational complexity of the process, the phase will be implemented successively over a period of 8 years, with the main infrastructure, such as OPS, likely to become operational only in the second half of the phase, the return horizon will extend beyond the implementation period. However, it is important to note that such a situation does not represent a financial risk. Fixed assets (OPS, electronic equipment, photovoltaic systems) have a technical lifetime of at least 20 years, which ensures that the port will generate a net positive cash flow for more than a decade after full commissioning. Any savings achieved after the investment payback point will represent a net surplus, strengthening the long-term fiscal sustainability of the green transition.

• Beyond Economic Metrics—The Value of Decarbonization

Although financial indicators, such as the payback period, are the ones that provide the basic guidelines for capital allocation, it is important to recognize that certain strategic steps, such as in this case achieving net-zero port operation, go beyond the conventional frameworks of costs and economic benefits.

Decarbonization of port activities is not only an imperative to comply with ever-evolving EU and IMO regulations but also a long-term investment in environmental management, regional leadership and intergenerational equality, the full value of which cannot be captured by monetary metrics alone.

• Uncertainty and adaptive management

It should be noted that these figures represent projections based on scenarios and are subject to variables such as the following:

• Actual costs of acquiring equipment, including potential deviations from estimated prices due to inflation, exchange rate changes or disruptions in global supply chains;
• Actual berth utilization rates and vessel demand for operational services, especially shore power supply (OPS) services, which are key to generating revenue;
• The actual level and dynamics of the profitability of subsidies, including the risk that EU funds (e.g., IPA III, CEF) will not be paid within the stipulated period or in full, which could lead to a temporary liquidity gap;
• Potential need for additional sources of financing, such as credit through the European Investment Bank (EIB), if there is a gap between planned and actually available funds.

To address this, the port will implement a digital monitoring and evaluation platform [14,40], enabling real-time monitoring of energy flows, emissions and financial performance. This system will enable continuous validation of assumptions and adaptive recalibration of operational and investment strategy.

Critical Risks and Mitigation Strategies

The second phase of the transition of the Port of Bar is characterized by more complex technological and infrastructural challenges associated with large-scale electrification, installation and commissioning of additional solar photovoltaic systems to and from the onshore energy supply system (OPS).

Many risks identified during the first phase remain relevant, especially those related to extended periods of preparation and issuance of permits for the installation of new solar capacities, project design and integration with the national grid.

Delays in the procurement and delivery of specialized electrical infrastructure may also occur due to market fluctuations, dependence on suppliers or geopolitical instability affecting the availability and prices of the required components.

A significant operational risk in this phase relates to the replacement and liquidation of existing equipment based on diesel engines. Since the planned investment strategy envisages a partial reinvestment of funds from the sale of old machines, any delay in the sale of assets could create a financial gap between the decommissioning of old units and the delivery of new equipment. Moreover, the technical condition of the current fleet by 2030 will directly affect its residual market value, affecting the total capital available for reinvestment.

Additional risks, which may occur during this phase of transition, are directly related to the dependence on continued access to EU funding schemes. As the second phase relies heavily on co-financing through the European Development and Cohesion Funds, any delay or change in eligibility criteria during future EU budget periods could affect the implementation timeline and the scale of planned investments. This financial dependence represents a critical uncertainty that could slow down the transition process if not anticipated through alternative financing mechanisms or contingency planning.

The implementation of OPS also brings additional technical risks arising from the need for comprehensive feasibility studies, energy demand simulations and capacity analyses of the existing electrical network. Given that most of the electricity supply to the TSO will depend on the national distribution grid, and potential grid stability and connectivity issues must be addressed in close coordination with the national energy distributor.

In order to mitigate these risks, the Port of Bar needs to establish an advanced framework for timely planning and asset management to synchronize the sale of old and acquisition of new equipment, with the aim of avoiding operational disruptions. Close and continuous cooperation with the national energy company and its subsidiary company is necessary to identify potential bottlenecks in the network and define the required upgrades well in advance of the deployment of OPS. Continued workforce investment in training as well as the employment of specialist energy management, automation and maintenance engineers will also be key to ensuring long-term reliability and operational resilience.

4.3. Monitoring and Evaluation Plan

In order to be able to successfully begin with implementation of the first Pilot phase, a number of preparatory steps need to be completed beforehand. One of those steps, possibly the key step, is the creation of a monitoring and evaluation plan.

Figure 9 shows a detailed approach to creating an M&E plan, which consists of four basic steps. This system enables transparency, accuracy and continuous improvement during the implementation of the desired measures.

4.3.1. Develop a Monitoring and Evaluation Plan

The goal is to develop a system for digital monitoring of key indicators in real time, which will also enable us to effectively evaluate the outcomes of implemented measures [14,40]. In this way, they would create a platform that would allow us to potentially identify all those fields subject to change, in order to successfully achieve the previously set goals at the end of each phase [103,128]. Such a system will provide continuous insight into the course of implementation of measures during the first Pilot phase, enabling timely detection of problems and deficiencies [27,28]. In this way, a sufficient time frame will be ensured for corrections and optimization of the strategy before moving to the second ambitious phase [25].

4.3.2. Monitoring and Evaluation Indicators

The first Pilot phase of the transition strategy of the Port of Bar toward the green port model extends over the period from 2026 to 2030 and is aimed at achieving specific goals that would provide a basis for further development of the sustainable port model [14,27]. The main goals include reduction in CO₂ emissions of at least 50% in comparison to 2024, increasing the share of renewable energy sources (RES) to ≥ 40%, replacing at least 50% of diesel port operational equipment with an electric version, as well as improving digital flows through upgrading the existing Port Community System (PCS) and modernizing the infrastructure [28,103].

Table 19. Key performance indicators (KPIs) for Phase I—Port of Bar (2026–2030).

Performance Indicator	Target Value by 2030	Method of Measurement	Frequency
Total CO2 emissions	−1500 tCO2 compared to 2024 baseline	Annual emission inventory report	Annually
Share of electric/e-zero emission equipment	≥30%	Inventory and operational data from port systems	Semi-annually
Share of solar energy in total consumption	≥70%	Energy monitoring system/smart meters	Quarterly
Cargo handling efficiency	+30% compared to 2024	Throughput analysis based on terminal operations	Quarterly
Digitalized processes	100%	Process mapping and digital workflow audit	Semi-annually

shows the key performance indicators (KPIs) that will be used to systematically monitor the progress of the Port of Bar within the first phase of the transition. These indicators include CO₂ emissions, the share of electrical equipment, the use of solar energy, the efficiency of cargo handling and the level of digitization of processes [28,128]. Each KPI defines a target value until 2030, a measurement unit, monitoring methodology and reporting frequency, which ensures transparency, accuracy and the possibility of continuous improvement [14].

The second ambitious phase of the transition strategy of the Port of Bar extends over the period from 2030 to 2038, aiming at achieving total decarbonization and modernization of the infrastructure [25,102]. This phase aims to achieve ambitious results such as a CO₂-free port, 100% use of renewable energy sources, electrification of all mobile operations, and automation of warehouse and cargo handling processes [28,129]. Additionally, the Port of Bar will seek to assert itself as a regional “Green Hub” through stronger connections with other Mediterranean ports [103].

Table 20. Key performance indicators (KPIs) for Phase II—Port of Bar (2030–2038).

Performance Indicator	Target Value by 2030	Method of Measurement	Frequency
Total CO2 emissions	0% (net-zero)	Annual emission inventory report	Annually
OPS System coverage	100%	Monitoring of shore power connections	Quarterly
Share of electric/e-zero emission equipment	100%	Inventory and operational data from port systems	Semi-annually
Share of solar energy in total consumption	100%	Energy monitoring system/smart meters	Quarterly
Cargo handling efficiency	+20% compared to 2030	Throughput analysis based on terminal operations	Quarterly

shows the key performance indicators (KPIs) that will be used to monitor the progress of the Port of Bar in the second phase of the transition towards a net-zero port model until 2038. Compared to Phase I, the goals are much more ambitious, with an emphasis on fully decarbonized operations, full electrification and process automation [14,128]. Additionally, the implementation of the OPS system (shore power) represents a new element that was not present in the first phase [27].

4.3.3. “Real-Time” Monitoring

Within the developed M&E plan, special emphasis is placed on monitoring performance in real time, which enables faster response to changes, continuous management of processes and more effective evaluation of implemented measures [48,127].

Using smart sensors, IoT technology and digital platforms, the Port of Bar will have the ability to continuously collect data on CO₂ emissions, energy consumption, cargo movement and infrastructure status [130,131].

This approach ensures a high level of transparency, accuracy and the possibility for predictive maintenance and therefore a greater resistance to possible interruptions or deficiencies in operations [132].

Real-time monitoring will be integrated into energy, logistics and terminal management systems, enabling necessary decisions and dynamic resource management during both phases of the transition [21,39].

4.3.4. Evaluate Outcomes

The evaluation of the output information within the digital monitoring system in the Port of Bar will be based on the interpretation of quantitative data on CO₂ emissions, energy patterns, cargo handling efficiency and the degree of digitization of processes, which are collected in real time through IoT sensors and digital platforms [26,38]. These data will be analyzed in accordance with clearly defined KPI standards, which are part of a wider monitoring and evaluation (M&E) plan, with the aim of evaluating the effectiveness of each applied measure and its contribution to the goals of a sustainable transition [22].

The application of KPI benchmarking enables a systematic comparison of actual performance with predetermined goals. Indicators such as CO₂ emissions per ton of cargo, energy consumption per unit of operation, and the share of electrified equipment allow a transparent and quantitative evaluation of the performance of each implementation phase [22,130]. Periodic evaluations will be carried out on a quarterly and annual basis using advanced software tools for analytics, including integration with digital twins, enabling the simulation of what-if scenarios [131].

In addition to KPI evaluation, the Port of Bar will use various methods such as predictive analytics and digital visualization in order to identify potential inefficiencies and to respond in advance to possible risks [1,132]. This approach, which combines technical precision, digital tools and performance evaluation, increases not only operational efficiency, but also overall resilience of the port in the context of decarbonization, energy efficiency and sustainable development [14].

5. Discussion

This discussion interprets the Port of Bar’s green transition roadmap through four interrelated dimensions.

Placing the planned port decarbonization phase plan in the wider EU, international and national frameworks, this section critically examines not only its technical and financial viability but also its institutional resilience, strategic dependencies and social value.

The analysis aims to integrate project-level planning with the systemic challenges and opportunities facing small and medium-sized ports.

5.1. Policy Alignment and Regulatory Implications

Looking at it through a regional framework, we can state that the roadmap is in line with the political directions of the European Sea Ports Organization, which promotes the integration of renewable energy sources, solutions for electricity supply from land and principles of circular economy within port operations [119,121]. The proposed solutions are also in accordance with the recommendations of UNCTAD and the International Maritime Organization, both of which encourage adaptive, context-specific transition for small and medium-sized ports in accordance with the IMO Initial GHG Strategy [95,120,127].

In this framework, the road plan positions the Port of Bar as a relevant and representative example that indicates that even the smaller ports of the eastern Adriatic can respond to the set goals of the EU and the IMO in terms of decarbonization, although their operations are partly conditioned by the limitations of local infrastructure and energy supply and are also subject to geopolitical influences.

By combining the gradual electrification of port equipment, the integration of renewable energy sources and the adoption of digital monitoring systems, the plan supports the broader objectives of the EU’s Sustainable and Smart Mobility Strategy, which emphasizes the creation of energy-efficient and interconnected maritime corridors within the TEN-T network [125,126].

Despite this strong alignment with international frameworks, several national policy and institutional gaps may still limit practical implementation.

Perhaps the biggest challenge is the absence of a unified national strategy for maritime decarbonization and the lack of a specific institutional mechanism responsible for coordinating the transition within the port and shipping sector. Although the National Energy and Climate Plan of Montenegro sees the expansion and use of renewable energy sources as a strategic goal, it unfortunately still does not include those measures specific to the port sector or maritime logistics, with the absence of mechanisms for monitoring and reporting on port-related emissions in accordance with EU standards for MRV [13,15]. Insufficient institutional coordination is also a type of limitation.

Financially, there are several regulatory and financial options that could accelerate the green transition if properly integrated into national policy. Montenegro’s status as a candidate country for the EU allows access to instruments for pre-accession financing, including the Instrument for Pre-Accession Assistance (IPA III), the Investment Framework for the Western Balkans and the Green Agenda for the Western Balkans, all of which directly support initiatives for the application of renewable energy sources and decarbonization in transport [13,15]. Furthermore, integrating the Port of Bar decarbonization roadmap into the upcoming revisions of the National Transport Strategy and the National Energy and Climate Plan would ensure stronger alignment with EU policy objectives and improve eligibility for EU Green Plan funding programs.

Strengthening institutional cooperation, policy coherence and regulatory harmonization will therefore be necessary steps to ensure the gradual integration of Montenegro into the low-carbon maritime transport network of the EU.

5.2. Economic Feasibility: Beyond Payback Periods

The economic assessment of the green transition of the Port of Bar reveals a financially viable path towards complete decarbonization, which, we can say, re-examines the assumptions regarding the cost burden of sustainability in small and medium-sized ports.

Unlike studies that present port electrification and the integration of renewable energy sources, i.e., the green transition as a whole, as capital-intensive undertakings that require large financial investments [1,5], the analysis carried out in this paper shows that almost zero net fiscal contribution of the port operator is possible through a strategic combination of asset monetization, national green grants and EU pre-accession instruments such as IPA III and CEF.

The proposed model offers a repeatable plan for small and medium-sized ports where public budgets are limited, but alignment with EU climate policy is both a political and economic imperative.

A particularly significant finding is the ultra-short payback period for Phase I, driven by synergistic savings from the elimination of costs that were previously separated for fuel use, and additional savings due to the partial use of solar self-consumption. This contrasts with typical return-on-investment horizons of 7 to 12 years, suggesting that smaller ports, often perceived as laggards and laggards in green innovation, may actually enjoy structural advantages, which include lower baseline energy demand, simpler infrastructure and greater flexibility in fleet renewal. The ability of Port of Bar to fully recoup its initial outlay in Phase 1 by reselling outdated diesel port equipment further highlights the hidden financial injection, i.e., a factor often overlooked in decarbonization models [5].

However, the economic logic changes significantly in Phase II, where the introduction of onshore electricity supply increases the capital expenditure and extends the payback period to almost 10 years. Although this exceeds typical private sector investment thresholds, it is aligned with the public good rationales underlying EU maritime policy. OPS is projected to generate minimal direct revenues with berth utilization of 40% but generate significant non-market benefits, including improved urban air quality, compliance with upcoming EU MRV and FuelEU maritime rules, and improved eligibility for future TEN-T co-funding. In this respect, the strategy of the Port of Bar reflects a broader trend observed in the ports of Gothenburg and Rotterdam, where OPS is treated not as a profit center but as a regulatory and reputational necessity [19,21].

What can be critical is that the financial sustainability of both phases depends on continued access to EU pre-accession funds, a dependency that introduces political and institutional risk. Montenegro’s candidate status provides a window of opportunity, but delays in IPA III payments or changes in EU budget priorities could jeopardize implementation. This highlights a systemic gap in the current green transition architecture for candidate countries: while the EU Green Plan and the Fit for 55 program establish binding environmental targets [48,49], they lack robust mechanisms to de-risk investments in non-member countries. The reliance of the Port of Bar from EU funds, which represents about 65% of the total capital expenditure, reveals a vulnerability that goes beyond the financial framework; it is a test of policy coherence between the enlargement and climate agendas [13,15].

Finally, and very importantly, the highlight is that the analysis confirms that monetary metrics alone cannot capture the full value of decarbonization. Achieving net-zero production positions the Port of Bar as a potential green hub for Southeast Europe, attracting ESG-aligned shipping lines and logistics partners. Furthermore, the projected creation of green jobs in solar energy maintenance, digital logistics and emissions monitoring directly contributes to Sustainable Development Goal 8 on decent work and Sustainable Development Goal 13 on climate action, as outcomes that are fully in line with EU just transition principles but perhaps remain absent from conventional cost–benefit frameworks [55,71].

In short, the case of the Port of Bar shows that economic profitability in small and medium-sized ports is not only a function of technology costs but of smart financing architecture, policy alignment and strategic positioning within regional value chains [14,25].

Future research should explore how digital twins and real-time monitoring and evaluation platforms, as planned in Bar, can further reduce investment uncertainty and optimize phase-out in heterogeneous port networks [27,28,131].

5.3. Global Supply Chains

A critical vulnerability that may affect the green transition model of the Port of Bar, in addition to the financial one, is also reflected in its high reliance and dependence on external suppliers.

As previously noted and analyzed, the EU pre-accession instruments, such as IPA III and CEF, are designed to provide the bulk of capital expenditures [13,15], the successful deployment of this funding depends not only on Montenegro’s political progress towards EU membership but also on the continued availability of specialized equipment and components from global markets.

The procurement of the necessary equipment and facilities is largely dependent on transnational supply chains that remain vulnerable to geopolitical instability, trade restrictions, and logistical bottlenecks [7,8].

Recent disruptions have already shown in the past how fragile “just-in-time” delivery models can be, especially for capital-intensive infrastructure projects in peripheral economies [7].

For a small port such as the Port of Bar, which lacks the bargaining power of larger EU hubs, delays in equipment delivery could translate into operational disruptions, missed funding windows and erosion of stakeholder trust.

Such a dependency can compound the risk that is rarely addressed in decarbonization roadmaps tailored to Western European ports [14,25]. Moreover, the absence of a national maritime decarbonization strategy or a specific risk mitigation framework for green infrastructure procurement further exacerbates the exposure [72].

Without proactive measures, which should include, among others, strategic storage of critical spare parts, supplier diversification beyond individual geographic regions or the development of regional maintenance partners with neighboring ports in the Western Balkans, the Port of Bar may find itself unable to implement even technically feasible measures. To improve resilience, future policy should integrate supply chain risk assessments into national green infrastructure planning and explore regional cooperation mechanisms within the Western Balkans Green Agenda to pool procurement and share technical capabilities [13,15,43].

5.4. Socio-Economic and Community Impact

In addition to environmental and economic benefits, the green transition of the Port of Bar is predicted to have significant social and employment implications. The gradual electrification of cargo-handling equipment, the implementation of renewable energy systems and the modernization of digital infrastructure will require the development of new professional profiles, particularly in renewable energy maintenance, digital logistics management and environmental monitoring. This structural transformation of the port’s employment base will foster the creation of “green jobs” and strengthen the local labor market’s adaptability to emerging technological demands.

Furthermore, the quality of life in nearby communities will be directly improved by the use of shore power systems and electric machinery to reduce local air and noise pollution. It is anticipated that cleaner operations and improved energy management will reduce health risks and help the municipality of Bar achieve its broader urban sustainability objectives. These social co-benefits highlight the port’s multifaceted transition and its alignment with the UN Sustainable Development Goals (SDGs), particularly those related to sustainable industry, decent work, and community well-being.

6. Conclusions

This study introduces a comprehensive, two-phase roadmap for the green transition of the Port of Bar, offering a replicable framework for small to medium-sized ports operating under transitional economic conditions. Unlike many studies focused on large and well-funded European ports, this paper provides an empirically grounded model that integrates operational data, theoretical modeling and expert consultation to guide the decarbonization of smaller port systems.

The main contribution and novelty of this research lie in the development of a mixed-method approach that combines quantitative KPI benchmarking, scenario-based optimization and qualitative AHP-based validation to assess technological, operational and governance measures.

Based on the conducted research, it can be concluded that the Port of Bar has realistic technical, regulatory and financial prerequisites for a successful transition towards sustainable and low-carbon business. The proposed transition model, which includes a clearly defined regulatory framework, a monitoring and evaluation plan with measurable indicators, as well as phased implementation in the periods 2026–2030 and 2030–2038, represents a practical basis for achieving the goals of decarbonization and electrification.

Application of clean technologies, increasing the share of renewable energy sources, and modernization of digital systems (PCS), will create conditions for a significant reduction in CO₂ emissions, greater energy efficiency and transparent process management. Of particular importance is the continuous monitoring of results through clearly defined KPIs, which ensures the possibility of timely corrections and optimization in each phase.

In the coming period, the key to success lies in the active cooperation of the Port of Bar AD with the Government of Montenegro, experts, the academic community, and relevant European institutions, with the provision of necessary investments and support through green funds and EU programs.

Despite its relevance and practicality, the research acknowledges certain limitations. The findings are constrained by data availability and expert-based assumptions, potential fluctuations in funding sources, and the need for adaptation when scaling to larger ports or multi-terminal complexes. External dependencies, such as regulatory changes, may also affect long-term outcomes. Nevertheless, the roadmap provides a robust foundation for adaptive management, allowing iterative monitoring and adjustment through real-time data analytics and performance indicators.

From an academic perspective, this research contributes to the growing body of literature on sustainable port development by bridging theoretical models of green logistics with empirical validation. It advances understanding of small-port decarbonization processes, offering a methodological framework applicable to other regional contexts.

From a managerial standpoint, the proposed model serves as a practical decision-support tool for policymakers and port authorities to plan, prioritize and evaluate sustainability investments. It demonstrates how digital transformation and green energy transition can be jointly leveraged to enhance competitiveness, compliance and long-term resilience.

Future research should focus on the longitudinal validation of transition outcomes, cost–benefit assessments of alternative fuels and autonomous operations and comparative studies with other Adriatic and Mediterranean ports. Such efforts will enable refinement of the model and strengthen its applicability across diverse maritime contexts.

In summary, the Port of Bar’s transition pathway exemplifies how small and medium-sized ports can pursue the dual objectives of decarbonization while maintaining economic viability, setting a precedent for sustainable port management in the wider Adriatic region.