Cold Ironing Implementation Overview in European Ports—Case Study—Croatian Ports

Abstract

Cold ironing technology, recognized as a tool to reduce emissions while ships are at berth, has been introduced in several European ports aligning with the international and European environmental and legal framework for reducing greenhouse gas emissions. The study aims to identify the prospects for cold ironing technology’s introduction into Croatian state-owned ports according to European sustainable conditions. The authors surveyed a group of port experts and stakeholders. Response analysis showed that the technology implementation in Croatian ports is feasible, but only 40% of state-owned ports currently dispose of a minimum electric connection power of more than 1 kV. Furthermore, the analysis showed that all surveyed experts confirmed a cold ironing technology application perspective in state-owned ports. Substantial investments and financing demands have to be concerned to achieve sustainable implementation. Significant efforts are still needed to overcome the challenges in the technology application requiring cooperation between stakeholders. The international legislative regulations implemented by the IMO insist on the safety of ships and people, respecting both the security of navigation at sea and overall operations in the port.

1. Introduction

Maritime transport is continuously increasing the movement of goods and people, with 90% of international traffic being carried by ships [1], which are considered the most fuel-efficient mode of transport in terms of ton-miles [2]. A significant number of port calls increases the energy pressure on ports that regularly serve vessels in daily operations. Energy demand has substantial environmental impacts through SOX, NOX, CO₂, and particulate matter emissions, neglecting the sustainability of energy consumption. The emissions directly affect human health and quality of life in the adjacent areas of the port. It is estimated that maritime transport emits 3% of global greenhouse gas (GHG) emissions, with a projected increase of 50% to 250% by 2050 if no further action is taken [3]. The mentioned year is a deadline according to the European Green Deal to fully decarbonize the shipping industry. Reducing hazardous emissions contributes to ports’ sustainability and green perspective [4].

In recent decades, numerous incentives and policies have been adopted to address the challenge of reducing GHG emissions, including the contemporary European Green Deal, which introduces drastic measures in the shipping industry to reduce pollutant emissions and introduce green, sustainable technologies [5]. To cope with pollution and emissions in seaports and adjacent areas, “Cold Ironing (CI) technology”, also known as “On-Shore Power Supply (OPS)”, “Alternative Marine Power (AMP)”, and “Shore Side Electricity (SSE)” [3], is one of the methods used to achieve sustainable maritime transport. Cold ironing technology refers to the use of shore power systems to generate ship electricity at berth. Normally, ships use auxiliary engines at berth to power equipment such as lighting, ventilation, pumps, cranes, etc. These engines use HFO (Heavy Fuel Oil), MGO (Marine Gas Oil), or MDO (Marine Diesel Oil) as fuel and cause harmful emissions to the atmosphere [6]. If cold ironing technology is introduced as port infrastructure, ships could be connected to a shore-based power source, allowing auxiliary engines to have a different power-load distribution [7]. It is also necessary to redistribute the ship’s power system to prepare it for shore connection.

The International Maritime Organization (IMO) has taken significant steps to reduce emissions of harmful gases from ships and improve safety at sea. The adoption of the IMO Directive in 2011 and the Greenhouse Gas Reduction Strategy in 2022 demonstrate the organization’s commitment to these goals [8]. The IMO is actively involved in 92 projects worldwide, the main objective of which is to adapt to climatic conditions in the maritime industry. One of the most important projects is “Toward Green and Efficient Navigation”, which will be implemented in 2022 and 2023. The port authorities of the city of Singapore are among the partners involved in the project [9,10]. However, the project requires significant financial resources to be accessed at local, regional, national, and international levels, and optimal synergy between stakeholders is necessary to achieve the project’s goals. Although there is no direct correlation between the implementation of cold ironing and the safety of navigation, an implicit link can be found in the benefits of cold ironing, particularly its ability to improve air quality and visibility for port workers and ship crews, contributing to the overall visibility in ports. This in turn has the potential to reduce the risk of accidents. In addition, the use of cold ironing technology can mitigate the risk of fires or explosions in the vicinity of the port city, which could be caused by improper handling of the ship’s fuel [11,12].

A further literature search revealed several relevant papers. In addition, special emphasis was placed on the literature dealing with the introduction of cold ironing in Croatian ports. In the ASAP (Adriatic Sea Area Protection) project, the authors focused on preventing air pollution from ship emissions. They concluded that effective solutions should be implemented through cold ironing, acknowledging the potential challenges and the need for well-defined financial support [13]. The authors in [14] discuss short sea shipping in Croatia and the associated environmental impacts with the incentive to use cold ironing for all ships involved in short sea shipping. The research by A. Cuculić et al. [15] is based on the economic and environmental aspects of applying cold ironing technology in the ports of Rijeka and Dubrovnik. Similar research objectives were also pursued in [3] where the author aims to analyze and study the technical, economic, environmental, and social aspects of introducing on-shore power supply in the Nordic countries. The author in [16,17] concludes that OPS is an effective way to reduce greenhouse gas emissions, air pollution, vibration, and also noise pollution. In [16], the authors also describe the implementation of a calculation method to approximate a specific environmental charge in ports to promote cold ironing technology, while in [17] the authors present CI technology as the most effective way to reduce ship-related emissions in the port area during the hoteling period. In [18], the feasibility of installing cold ironing in a medium-sized port was discussed, and it was concluded that the ferry type is most suitable for cold ironing in medium-sized ports. In addition, the feasibility of cold ironing depends on the activity and composition of port traffic, especially during berthing periods and ship calls, as discussed in [1]. In the selection of ship types, the main potential users of cold ironing technology were identified, namely cruise ships [18,19,20,21] and ro-ro ships [18,19,20,21]. The vessel type factor is used as one of the determinants to create

Table 1. European seaports with functional cold ironing technology.

Country	Port	Implementation Year	Type of Vessel	Reference
Belgium	Zeebrugge	2000	RoRo	[22]
Belgium	Antwerp	2008	Container	[23]
Finland	Kemi	2006	RoPax	[23,24]
Finland	Kotka	2006	RoPax	[23,24]
Finland	Oulu	2006	RoPax	[25]
France	Dunkirk	2020	Container	[26]
Germany	Lubeck	2008	RoPax	[25]
Germany	Hamburg	2016	Cruise	[27]
Germany	Kiel	2019	Cruise	[28]
Netherlands	Rotterdam	2012	RoPax	[25]
Norway	Bergen	2022	Cruise	[29]
Sweden	Gothenburg	2000 & 2010	RoRo, RoPax	[22,30]
Sweden	Stockholm	2006	RoRo, RoPax, Archipelago ferries	[31]
Sweden	Karlskrona	2010	RoPax	[22,30]
Sweden	Ystad	2012	RoPax	[30]
Sweden	Trellebrog	2013	RoPax	[22,30]
UK	Southampton	2022	Cruise	[32]

, which can help in decision making for the implementation of cold ironing technology in ports. The approach also acknowledges that different vessel types may have different requirements and challenges in adopting cold ironing, which highlights the importance of considering vessel types in the analysis. Using the literature review of ports that have installed cold ironing technology, the authors compiled a list of ports, some of which are located near cities or in urban centers and thus negatively impact local communities through emissions. The close connection between ports and urban areas is frequently observed in Croatia as can be seen in the example in Figure 1.

This paper aims to analyze the application circumstances of cold ironing technology in Croatian state-owned ports. Because this technology is already used in a considerable number of propulsive European seaports (see Table 1), which to some extent have similarities with the state-owned ports in Croatia, such as the port of Split (see Figure 1), the question arises about the prospects for the use of on-shore power supply systems in the state-owned ports of the Republic of Croatia. By conducting a survey on a group of state-owned port experts who are official representatives of the ports of Dubrovnik, Ploče, Split, Šibenik, and Zadar, as well as experts and stakeholders from private companies and maritime-oriented institutions, results were obtained on the current and future implementation aspects of the technology. Because there are currently no concrete plans for cold ironing technology implementation in the seaports of the Republic of Croatia, it is necessary to obtain an application perspective that considers the increasing concern about the trends in the energy sector in light of ongoing global events and compliance with international and European emission reduction plans. In addition, this study aims to provide an overview of the challenges associated with the introduction of cold ironing technology in the state-owned ports of the Republic of Croatia from an economic, technical, environmental, and social perspective. The research aims to assist in developing a thorough overview for the seaports regarding the research goals. Moreover, this study aims to bridge the existing knowledge gap by providing decision makers with a comprehensive understanding of the potential of cold ironing technology and its implementation in seaports.

This paper is divided into seven sections. The first section is the introduction. The second section discusses the environmental incentives, documents, policies, and the legal framework in the European Union and Croatia. The third section provides a brief overview of the advantages and challenges of cold ironing technology, which sets the context for the following sections. The fourth section describes the method used in the study, while the fifth section presents the results of the study. The Discussion section summarizes the study’s results along with the brief overview of the framework proposal in Croatia and the relevant literature. Finally, the Conclusion section examines the limitations of the study and provides recommendations for future research.

2. Environmental Incentives and the Legal Framework—European Union and the Republic of Croatia

In the face of increasing concern about greenhouse gas emissions, international and European institutions have developed various regulations to incentivize the adoption of environmentally friendly technologies. Because shipping and ports contribute 3% of greenhouse gas emissions [3], 2% of CO₂, 10 to 15% of NOX, and 6% of SOX [33] to global emissions, regulations were needed to encourage shipping and port stakeholders to reduce air pollution and adopt energy-efficient environmentally friendly technologies. The IMO has issued several regulations to reduce greenhouse gas emissions. The MARPOL Annex VI of the International Convention for the Prevention of Pollution from Ships introduced technical and operational measures for energy efficiency measures [3]. The IMO has also adopted a strategy to reduce GHG emissions from shipping by at least 50% by 2050, with the goal to fully decarbonize the shipping industry by the end of the century [34].

Since 2010, the Community ports of the European Union have required a maximum sulfur content of 0.1% by weight for marine fuels used by ships at berth. The European Commission has recommended that ships in ports located near residential areas use shore power to maintain the air quality in ports. Simultaneously, European guidelines call for the implementation of port facilities to be included in the national policy frameworks of European countries to facilitate faster conversion and deployment of shore-side power [16]. The European Sea Ports Organization (ESPO) supports ports in the implementation of on-shore power supplies (OPS) concerning air quality management and advocates the assessment and reduction of port fees for the proactive use of cold ironing technology [35]. In 2019, the European Commission presented the Green Deal Strategy with the goal of achieving sustainable development of the European economy. This can be achieved by transforming environmental challenges into opportunities for various policies that will ensure the transition to decarbonization with investments of more than EUR 250 billion [5,36]. In the proposal for the EU legislative package “Fit for 55” under the Green Deal, the promotion and implementation of cold ironing is supported. The Alternative Fuels Infrastructure Regulation (AFIR) is proposed as a revision of Directive 2014/94, which requires, among other things, that ports have shore power supply infrastructure to supply passenger ships and container ships of GT over 5000 from the beginning of 2030 [37]. The European Community Shipowners’ Association (ECSA) calls on the Commission to assess the importance of alternative fuel supply infrastructure in European ports, including shore power. Under the Green Deal, the Commission requires docked vessels to use shore-side power. In addition, ECSA invites the Commission to consider measures to facilitate the use of shore-side electricity from renewable energy sources by docked vessels [34].

Croatian regulators support green technology initiatives to reduce GHG emissions through several strategies, namely:

• The National Development Strategy of the Republic of Croatia until 2030 defines, among others, the application and development of green and sustainable technologies in various economic sectors in line with the European Green Deal [38];
• The Energy Development Strategy of the Republic of Croatia until 2030, with a view to 2050, discusses a vision of a low-carbon economy. The strategy defines the pace of energy sector changes in technologies, devices, transportation, energy consumption, and other factors. It also indicates Croatia’s contribution to the global reduction of greenhouse gas emissions in accordance with international commitments [39,40];
• The Transport Development Strategy of the Republic of Croatia for the period from 2014 to 2030 discusses the sustainability of ports by reducing their impact on the environment through increased energy efficiency, promoting the use of alternative fuels and establishing emission control areas. The aim is to ensure the long-term sustainability of the maritime sector, modernize port superstructure and infrastructure, and promote the use of renewable energy sources in the port sector. This also includes the establishment of a “clean air” program in order to reduce ship emissions in ports [41];
• The Croatian Strategy for Hydrogen by 2050 is consistent with the goals of the European Green Deal Strategy and the European Strategy for Hydrogen. The strategy explicitly mentions the supply of electricity to ships at berth and highlights the application of cold ironing technology as an important element in ports with a significant number of cruise calls such as Dubrovnik, Split, and Zadar [42].

3. Implementation Advantages and Challenges

More than 90% of European ports are located in urban areas, with passenger terminals in close proximity to city centers. It is worth noting that the state-owned ports surveyed in the Republic of Croatia are situated in urban areas and close to city centers. As an example, Figure 1 depicts the port of Split in Croatia and port of Kiel in Germany. Increasing health concerns, climate change awareness, and environmental legislation are forcing European port authorities to reduce harmful emissions [43]. As shown in Table 1, several European ports have already introduced cold ironing technology. Due to strict environmental policies and social awareness, most cold ironing facilities are located in Northern Europe [22]. Cold ironing technology is an effective method for reducing emissions [16,17]. Although the technology is effective [18], some challenges should be addressed.

Figure 1. Port of Split (left) [44] and port of Kiel (right) [45] urban integration.

Figure 1. Port of Split (left) [44] and port of Kiel (right) [45] urban integration.

Figure 2 displays the six state-owned ports in Croatia: Rijeka, Zadar, Šibenik, Split, Ploče, and Dubrovnik. Further information provides concise port specifics [46]:

• The port of Rijeka is a development-oriented port with specialized basins for handling various types of cargo. It is the largest Croatian port in terms of transportation and handles a wide range of cargoes, including containers, bulk cargo, and crude and refined petroleum products. The port can accommodate several vessels, such as tankers, bulk carriers, container ships, general cargo vessels, passenger ships, and ro-ro vessels;
• Zadar is a vital transportation hub in Croatia that connects continental traffic routes, maritime routes, railways, highways, and airports. The port meets international, national, and local requirements, including tourism, and the ferry terminal serves as the primary link to nearby islands and other coastal destinations. The Zadar Port Authority governs different port areas, including passenger terminals, cargo, and fishing ports;
• The port of Šibenik operates handling, transport, and storage machinery and has the necessary railway, road, electrical, and telephone infrastructure. It features terminals for bulk and general cargo and passengers;
• Split is the largest passenger port in the Republic of Croatia, and national and international traffic has been continuously increasing, indicating further growth trends. The port handles more than 5 million passengers and 730 thousand vehicles annually;
• The Port of Ploče serves as the main gateway to the Pan-European Corridor Vc and is the second-largest port in Croatia regarding annual cargo volumes, just behind the Port of Rijeka. The port terminals facilitate different types of cargo, including general, container, dry bulk, and liquid cargo;
• Finally, the Port of Dubrovnik plays a critical role in international passenger transport and is one of the most significant cruise ports in the Mediterranean area. The port primarily focuses on passenger transport in international and domestic freight, and the reconstructed port terminals are predominantly used for ferries and cruise vessels.

3.1. Advantages

The use of on-shore power allows ships to shut down their generators and auxiliary engines, consequently reducing emissions, noise, and vibration and improving the quality of life for the population in the adjacent port area [48,49]. It was calculated that a ferry with a capacity of 2400 passengers emitted 260 kg NOX, 16 kg CO, 35 kg SO₂, 6.2 kg particulate matter, and 12,050 kg CO₂ during a single 10.5 h berthing period [50]. During this time, the ship consumed 3754 kg of fuel and 15,420 kWh of electricity [50].

Arguably, the economic benefit of the technology is related to the regular use of the expensive low-sulfur marine fuel, considering the rising price trend of fossil fuels [13]. The return on investment for the CI establishment is from selling electricity to the ships and the socio-economic benefit of pollution reduction, based on the assumption that external health costs would balance capital investments [51]. The on-shore power reduces port gas emissions by 48–70% CO₂, 3–60% SO₂, 40–60% NOX, and 57–70% black carbon. The benefits were also observed in ports without sulfur emissions (SECA) [52]. Based on the research results from the authors of [53], it was found that up to USD 128 million in environmental benefits could be realized if on-shore power systems were deployed in the Chinese port of Dalian from 2020 to 2035. Another author stated that the total health benefits of cold ironing in European ports would be up to EUR 2.94 billion in 2020, with carbon dioxide emissions reduced by up to 800,000 tons [19]. Cold ironing is particularly effective in reducing greenhouse gas emissions over the long term because, unlike other measures, the technology can be implemented relatively quickly. According to an analysis conducted for the European Economic Area (EEA) and the United Kingdom, 3 million tons of carbon emissions per year could be reduced through the use of on-shore power supply and this figure could be multiplied in countries with a higher share of renewable energy, such as Sweden and Norway [6]. Similar findings can be observed in [54] where the authors suggested that the use of cold ironing technology can reduce pollutants by more than 70–80%.

3.2. Challenges

Economic concerns are one of the challenges related to the cold ironing implementation feasibility. The financial investments in the technology are significant for ports and shipowners. They also vary depending on the technical options such as voltage, frequency, cable management systems, maintenance, and the need for onboard transformers and/or onshore converters [19,30]. Retrofitting an existing vessel with shore power equipment could be more expensive than the additional cost for a newbuild vessel. Furthermore, there are no operational business models for cold ironing technology applications for seaports, and there is uncertainty about the number of ships connected to the OPS. For shipping companies, the financial concerns are related to the potential operational savings or losses when ships are at berth, which implies the cost relationship between electricity costs and the use of low-sulfur fuel [13,30]. However, this may change in light of future fuel price trends [37].

Another difficulty that should be addressed is related to the technical aspects of the broader application of the technology. It lies in the incompatibility between the ship and the power grid, because there is no standardized voltage and frequency. The lack of uniformity resulted in a variation from 440 V to 11 kV. On the other hand, some ships use 220 V at 50 or 60 Hz [24]. Therefore, setting up a series of frequency conversion systems is necessary. It is important to note that European power grids generally operate at 50 Hz [1]. The technical obstacles also vary depending on the type of ship. Cruise ships have a significant demand for electricity, which means that ports must have adequate power supplies, transmission networks, and power management strategies. This could require significant changes to the power grid and overall port infrastructure, resulting in higher costs [48]. In general, introducing cold ironing technology increases the port’s energy requirements [33]. According to [50], cold ironing does not eliminate GHG gasses and priority pollutants but outsources them to the electricity-generating industry. To optimize the sustainability of cold ironing technology, the electricity used to charge the vessel should come from renewable sources.

4. Methodology

The authors conducted research to explore the potential implementation of cold ironing technology in Croatian seaports, similar to some European ports (as shown in Table 1). A study was conducted to point out the emissions at ports, which may influence the determination to implement novel technology. The survey results were analyzed, affirming the application perspective in all surveyed state-owned ports. The authors found that state-owned ports have the highest potential for implementing cold ironing technology, particularly considering their established collaboration with various stakeholders, such as state and private entities, European regulatory bodies, and experience with European funding. The target audience for the research was identified based on the parameters above: state-owned ports and public and private companies involved in the port operations. A survey was created accordingly, and during the second quarter of 2022, the authors conducted the survey using an electronic communication data collection method distributed to the official public email domains of the targeted state-owned ports and stakeholders. The survey contained detailed instructions and was requested to be completed by official state port and stakeholder representatives to ensure the data’s accuracy and quality.

To investigate potential applications of cold ironing technology in Croatia, a survey was conducted and distributed to stakeholders (official representatives of ports) in the state-owned ports of Rijeka, Zadar, Šibenik, Split, Ploče, and Dubrovnik, as well as to experts and stakeholders from private companies and maritime institutions. To understand the research, it is important to know that Croatia has six state-owned ports (Figure 2) [46]. The survey consists of two parts. The first part collects general relevant data about the state-owned port, such as the form of electricity supply, the type of vessels that can currently be connected to conventional shore power supply, the development of electricity costs, and the plans for the future introduction of the cold ironing technology. This part also examines the approximate timeline for the introduction of the technology, its financing, and the interest of shipowners in cold ironing technology implementation. The second part of the survey was conducted among both public (excluding ports) and private companies in the Republic of Croatia. The aim of this survey was to obtain relevant data on the participation of companies in the implementation of cold ironing technology in the state-owned ports of the Republic of Croatia. In addition, this survey aimed to investigate what impact the introduction of such technologies could have on the general safety standard of shipping. The details of the survey and questions can be observed in the Appendix A.

In addition to descriptive, classification, analysis, and synthesis methods used throughout the paper, the research on the feasibility of implementing cold ironing technology in state-owned ports in Croatia primarily employs survey, case study, and statistical analysis approaches. These methods provide a comprehensive and in-depth analysis of the potential for implementing cold ironing technology. The survey was used to gather primary data from the state-owned port experts and stakeholders involved in the port operations. The case study provides a detailed analysis of the implementation of cold ironing technology in Croatian ports, including the benefits and challenges faced by the experts, stakeholders, and decision makers during the possible implementation phase. Finally, statistical analysis was used to analyze the survey data and identify trends and potential implementation barriers. By utilizing these methods, the research comprehensively analyzes the feasibility of implementing cold ironing technology in Croatian state-owned ports. It provides key insights that can inform decision-making processes for implementing this technology.

5. Results

The survey “High Voltage Shore Connections in state-owned ports of the Republic of Croatia” contained the required explanations and was completed by five of the six surveys sent out (83.33% is a representative result). The expert group consists of the state-owned port official representatives involved in the port’s different topic-related processes. One official representative from each of the state-owned ports of Zadar, Šibenik, Split, Ploče, and Dubrovnik participated in the survey.

Figure 3 shows the status of shore power supply type in a state-owned port. According to it, high-voltage connections with more than 1 kV are available in 40% of the ports, while connections with less than 1 kV are accessible in another 40% of the ports studied. Twenty percent of the ports have no shore power connection, and the DC connection is not available for all ports studied.

Table 2. Types of ships that can currently be connected to the conventional shore power.

		State-Owned Port
		Zadar	Šibenik	Split	Ploče	Dubrovnik
Vessel type	RoPax/RoRo
	Bulk carriers
	Tanker
	Cruise
	Excursion boat	X	X	X	X	X
	Nautical tourism vessels	X			X	X
	Smaller private boats	X			X	X
	Catamarans			X

follows on from Figure 2 above. The experts were asked to choose the type of ships that could be connected to the conventional shore power grid. As shown, inadequate infrastructure prevents RoPax/RoRo, bulk carriers, tankers, and cruise ships from connecting to the shore power grid. On the other hand, excursion boats can connect to the conventional shore power supply system in all observed ports. A similar case is observed in the port of Split, where catamarans can also connect their cables to the conventional shore power supply. The port of Zadar allows connection for nautical tourist vessels and smaller private boats, as well as in the ports of Ploče and Dubrovnik.

All respondents confirmed a perspective for the introduction of cold ironing technology in their ports. According to the experts, Figure 4 shows the approximate time it will take for alternative marine power to be fully operational in their ports. For 20% of the ports, there is no defined cold ironing technology implementation perspective. The results show that 60% of the ports need a period between one and five years for implementation. Finally, for 20% of the experts’ answers, the application period is more than five years.

Regarding the funding preferences (Figure 5) for cold ironing technology infrastructure, 60% of the ports’ experts opted for dual funding with port funds and European Union co-financing. On the other hand, 40% of the port experts prefer exclusive funding from state and/or European funds.

Table 3. Ship types for which shipowners showed interest in a cold ironing connection.

		Port
		Zadar	Šibenik	Split	Ploče	Dubrovnik
Shipowners’ interest for vessel type	RoPax/RoRo			X
	Bulk carriers
	Tanker
	Container				X
	Cruise		X	X
	Excursion boat	X				X
	Nautical tourism vessels	X				X
	Smaller private boats					X
	Catamarans

shows the general interest of shipowners in connecting their vessels to cold ironing technology in a state-owned port in Croatia. According to the experts at the Port of Šibenik, shipowners have expressed interest in cruise ships, while at the Port of Split, the interest is in RoPax/RoRo and cruise ships. In the port of Zadar, there is interest in excursion ships and ships for nautical tourism. For the port of Ploče, shipowners are interested in container vessels for cold ironing connection. It is worth mentioning that the official representative from the Port of Ploče added the container vessel type in the response. For the port of Dubrovnik, shipowners are interested in connecting excursion boats, nautical tourism vessels, and smaller private boats to the on-shore power supply.

Finally, Figure 6 shows the experts’ opinion on possible price increases in energy, especially electrical energy, in light of current global events and the possible effect on the port industry. Sixty percent of port experts believe that the increase in energy prices will have an impact on port business. Twenty percent of port experts are undecided, while the other twenty percent cannot assess the likelihood of the energy price increase on port operations and business.

Six different legal entities, which are recognized stakeholders, including public (excluding ports) and private companies and organizations, in the Republic of Croatia, participated in the second phase of the survey entitled “Enhancing Navigation Safety through the Implementation of High-Voltage Shore Connections within State Ports in the Republic of Croatia”. A group of 11 participants took part in this survey stage, with involvement from officials holding senior positions in six companies and organizations that were surveyed. All participating legal entities completed the survey, resulting in a response rate of 100%, indicating the successful completion of the survey.

Figure 7 shows that a significant proportion of surveyed companies in the Republic of Croatia are not engaged in the implementation of cold ironing technology in state ports in any way. Specifically, 63.6% of the surveyed participants stated that they have no contact with the mentioned technology. The remaining 36.4% of participants have dealt with the technology to some extent, of which 18,2% had direct or partial contact with the technology in question.

Figure 8 illustrates a notable result of the survey: a large majority (90.9%) of respondents believe that the introduction of cold ironing technology would have a positive impact on increasing safety in navigation. The survey results are in line with the International Maritime Organization’s (IMO) guidelines and strategic objectives to improve maritime safety [8].

6. Discussion

The shipping industry is burdened with pollutant emissions, while the port population is directly affected during ships’ berthing period. Over time, numerous strategies have been developed to combat emissions from ships. One of the possible solutions that has been adopted by several European ports is cold ironing technology. As discussed in this study, the circumstances and specifics of the technology must be met in order to successfully implement cold ironing technology. Currently, there is no functioning on-shore power supply in Croatian ports. Given the restrictions and measures introduced by international and European regulatory authorities, the prospects for the application of cold ironing technology in the most propulsive and significant state-owned ports in Croatia have been questioned.

The research showed that 40% of state-owned ports in the Republic of Croatia are eligible for cold ironing technology implementation, considering the required power of more than 1 kV (see Figure 2). Sufficient power supply is one of the fundamental prerequisites for the use of shore power, as the power demand for certain types of vessels is significant, as stated in [48] and [20]. Another 40% of ports have a power connection of less than 1 kV, while the rest (20%) do not have a necessary power connection. Considering the above results, 60% of the ports lack adequate infrastructure, resulting in higher start-up costs for cold ironing technology implementation projects, as stated by the author in [48]. Although most of the observed state-owned ports can supply conventional power to a range of vessel types (Table 2), the inadequacy of concrete measures to introduce cold ironing technology is evident. Sixty percent of port experts indicated that it would take between one and five years for cold ironing infrastructure to become fully operational (Figure 3). Two of the ports from the observed “one and five years” timeframe do not have a power connection greater than 1 kV, while the port with a power connection greater than 1 kV does not have a defined timeframe for the technology’s introduction.

To cope with the substantial financial investment, 60% of port experts suggest that cold ironing technology should be co-funded by both the port and the EU, and the rest have opted for funding from state and/or EU resources, as shown in Figure 4. Nevertheless, adequate and defined financial support is of great importance for a feasible implementation of cold ironing technology, which agrees with the authors in [13]. Regardless of the type of funding, it should be recognized that Croatian ports have sufficient experience with European funding, which should be considered as an opportunity to meet GHG emission-free deadlines. Another cost impact that should be considered is the development of energy prices related to the current global events. More than half of port experts agreed that energy price trends will have an impact on their port operations (Figure 5). If electric power becomes more expensive, it may suspend any narratives for on-shore power supply, while ports that are viable for on-shore power should consider competitive models for shipowners to reduce the uncertainty of the cost relationship between electricity and fuel.

Shipowner interest in cold ironing technology at state-owned ports (Table 3) correlates closely with the type of vessels calling at the port. It also corresponds to the main potential ship types for cold ironing, namely cruise ships [18,19,20,21] and ro-ro ships [18,19,20,21]. The activity of certain ship types and the number of port calls are higher in some ports than in others. The high activity of vessels in certain ports makes them a suitable environment for the development of business models that can facilitate the adoption of cold ironing technology and bring benefits to both ports and shipowners, provided the appropriate model is applied.

From the survey results presented in Figure 6, it can be observed that a considerable proportion of the companies operating in the Republic of Croatia are not engaged in any initiatives aimed at implementing cold ironing technology in state-owned ports. Despite this fact, the state-owned and private companies surveyed positively assess the potential impact of cold ironing technology on enhancing navigation safety of shipping, as well as the overall safety in ports [11,12], as shown in Figure 7. This result is consistent with the International Maritime Organization’s (IMO) strategic goals for improving maritime safety [8,9,10].

Considering the Croatian regulations, it is safe to say that they are in line with the international and European strategies to reduce GHG emissions, achieve the zero-emission target, and ensure safety at ports during navigation. As mentioned above, there are several strategies that promote the sustainability of the maritime sector, the vision of a low-carbon economy that considers the factors of transportation and energy consumption, and the clean air program [38,40,41]. Of the above strategies, only the “Croatian Strategy for Hydrogen by 2050” explicitly mentions cold ironing and its application in ports [42]. While institutions and policies promote green technologies, the lack of appropriate guidelines and adequate government and financial support is one of the reasons why the state-owned ports in Croatia do not incentivize cold ironing applications.

Based on the survey findings, the authors propose several frameworks or models for successfully implementing cold ironing technology in Croatian state-owned ports. These frameworks include [13,30,51,55,56,57]:

• Conducting a thorough feasibility study to assess the costs, benefits, and environmental impacts of implementing cold ironing in Croatian state-owned ports;
• Collaborating with other ports in the European Union, particularly those located on the Adriatic Sea, to evaluate and quantify the effects of cold ironing on the entire cluster of ports. This could facilitate the sharing of best practices and resources among ports;
• Developing a comprehensive cold ironing implementation strategy that considers the unique challenges and requirements of the technology;
• Investing in necessary infrastructure and providing workforce training that ensures ports are fully equipped to handle the technological, environmental, and safety challenges of cold ironing;
• Engaging with various ministries of the Republic of Croatia to ensure that implementing the technology aligns with relevant policies and regulations.

The authors also propose a partnership-based implementation approach that involves different stakeholders, including government, public institutions and businesses, the private sector, and academia [30,49,51,54,58,59]:

• Government-led framework: The government can lead the cold ironing implementation by providing funding, creating policies and measures, and setting up viable infrastructure. This approach can help ensure compliance with emission policies and promote the adoption of green port technologies;
• Private sector-led framework: Private companies operating in Croatian ports can invest in cold ironing technology and collaborate with other stakeholders to drive its adoption. This approach could also include collaboration with the ship owners considering their interest in the technology;
• Public–private partnership (PPP) framework: the government and private sector can collaborate to implement cold ironing technology, combining public funding and private sector expertise;
• Multi-stakeholder framework: Various stakeholders, including government, private sector, and academia, can work together to implement cold ironing technology. This approach can help address the unique challenges of implementing cold ironing technology and ensure a coordinated effort towards decarbonization goals.

The proposed frameworks provide comprehensive and strategic planning for successfully implementing cold ironing technology in Croatian state-owned ports. The suggested frameworks and implementation approaches offer a flexible and collaborative approach to address the challenges of implementing cold ironing technology and achieving decarbonization goals.

7. Conclusions

To conclude, introducing cold ironing technology in Croatia’s state-owned ports requires substantial financial, technical, and know-how resources, which can be obtained through state and/or EU funding. Specific institutional guidelines and plans would improve the prospects for the use of on-shore power in ports of state significance. Guidelines for business models for ports with considerable calls should be introduced. Such models should be beneficial to both the port and the shipowners. Institutional policies, plans, and business frameworks should be developed with experienced stakeholders in port activities, shipowners, green technology, and cold ironing technology. Applying green technologies, such as cold ironing, would make the port and shipowners more competitive and sustainable while benefiting the adjacent port population and the environment. Increasing energy prices, especially those related to electricity, are a concern for port operators, which may lead them to prioritize economic considerations over the implementation of sustainable, environmentally friendly technologies. Bearing in mind experts’ opinions, cold ironing technology implementation depends greatly on the government and regulatory ministries. A necessary port development strategy complying with the regulations and international acts is a prerequisite for contemporary ports. That is why the authors investigated fundamental conditions and obstacles concerning cold ironing technology based on expert opinions in Croatian state-owned ports. Investments in renewable energy sources should be encouraged to meet the energy price trends and benefit the power infrastructure for cold ironing technology. Efforts to reduce emissions must come from all environmental and port stakeholders. Therefore, the conjunction of activities, projects, strategies, and plans with them is necessary.

The importance of this research lies in its establishment of a framework for the implementation of cold ironing technology in the state-owned ports of the Republic of Croatia. Through the application of scientific methods and analysis based on the survey, the study has produced valuable insights and assumptions that can assist decision makers in future endeavors to implement cold ironing technology in state as well as non-state ports throughout Croatia. This study has contributed to the growing body of knowledge on sustainable, environmentally friendly technology in the maritime industry, and its findings can serve as the basis for policies and strategies that promote the adoption of cold ironing technology in Croatian ports. The results of this research serve as a solid foundation for future studies examining the feasibility, different frameworks, benefits, and challenges associated with cold ironing technology and can provide a useful reference point for stakeholders seeking to introduce this technology in other port systems worldwide. Ultimately, the implementation of cold ironing technology can enhance the competitiveness and sustainability of the port sector in Croatia while benefiting surrounding communities and the environment.

This study is subject to certain limitations as it relies on limited sample sizes for both parts of the survey. In the first part of the survey, six surveys were sent to the state-owned ports, with five completed (the survey was completed by authorized representatives of five of the six state-owned ports). On the other hand, officials from all six public (excluding ports) and private legal entities answered the second section of the survey, resulting in 11 completed surveys. Additionally, limited data were available on port strategies and plans related to cold ironing technology in Croatia, and a broader view of the sector could be provided by examining other sustainable technologies for implementation in ports. It is critical to define the specific onshore power requirements for each port to ensure successful implementation of cold ironing technology. To gain a complete understanding of how the implementation of cold ironing technology is related to different frameworks, it is essential to explore them thoroughly and conduct further research. Future research could also focus on how to increase the level of engagement of companies in the implementation of cold ironing technology.