Authors: Dr. Theo Notteboom, Dr. Athanasios Pallis and Dr. Jean-Paul Rodrigue

Ports can play a role in setting circular supply flow principles in terms of materials, energy, land and waste management.

1. Circularity and the Circular Economy

Production systems and the related supply chains tend to be organized linearly through a sequence involving the extraction of resources and materials, their transformation, manufacturing, and distribution. At every step, particularly after final consumption or the end of product lifecycles, wastes are generated and need to be discarded. However, in conventional supply chains, a rather small fraction of wastes are reused or recycled, mostly because production systems may not be designed to reuse some materials or because new materials may be easier and cheaper to procure. As environmental concerns emerged in the 1980s, greater pressures were placed on developing recycling capabilities with the emergence of concepts such as closed-loop production systems and “cradle to cradle” designs. The goal was to shift as much as possible from linear processes oriented along the “extract-manufacture-consume-dispose” paradigm toward circular processes such as “reduce-reuse-recycle”.

This circularity was eventually conceptualized in a wider context and became known as the circular economy (CE).

The circular economy is a feedback system that tries to minimize the inputs of resources as well as the generation of wastes leaking into the environment.

The circular economy emphasizes reducing waste and promoting resource efficiency through recycling, reusing, and remanufacturing. It applies well to products and assets with longevity and is less suitable for products with a short life cycle. For instance, assets such as vehicles and appliances can be better designed with CE principles than products such as clothing and even mobile phones. From a supply chain perspective, circularity is expanding reverse logistics principles into a more comprehensive framework, including two subsystems: one related to biological goods (e.g., food) and the other to technical goods (products). Four fundamental principles help define circularity:

• Maintenance. A product can be regularly serviced and upgraded to expand its life cycle before becoming obsolete or unusable.
• Reuse. A product can be transferred from one user to another by using a form of leasing or sharing involving collection, maintenance, storage, and delivery.
• Remanufacture. The manufacturing of a new product from similar products once it has ceased to function because of damage or wear and tear. The manufacturer refurbishes major parts and adds new components for the parts that cannot be repaired if necessary. Then, the product is reintroduced into the supply chain.
• Recycle. Once consumption occurs, discarded products can be collected and used as inputs in manufacturing other products.

Implementing these principles requires two fundamental changes within supply chains:

• Product design. Conventionally, products are designed to be single-use and discardable. The goal is to design products that can be modular, upgradable, and of longer duration. At the end of their life cycle, it should be possible for the product to be disassembled, reused, and recycled. A challenge concerns that technological developments incite the design of products with short life cycles.
• Feedback loops. Capabilities to incorporate feedback loops need to be developed so that circular supply chains become operational. Through feedback loops and their collection mechanisms, goods can be shared, reused, remanufactured, or recycled. A challenge concerns that feedback loops can be complex and costly to implement.

The CE brings forward the concept of extended producer responsibility, imposing on manufacturers and distributors a higher degree of responsibility for the environmental externalities of the goods they produce. This involves increasing involvement, even covering some of the related costs, over three main cycles: production and distribution, consumption and recycling. Improving the production and distribution cycle, mostly through improved product design, is expected. Further, the consumption cycle allows for extended longevity of the product, namely a capacity to reuse, and once a product is discarded, mechanisms should be in place to ensure that it enters the recycling cycle. During the latter, goods are collected, sorted, and reprocessed, eventually transformed as manufacturing inputs, thus reentering the production cycle. The concept of extended producer responsibility also involves a form of legal and economic responsibility. However, this raises ethical and legal issues as the burden is placed on the producers and distributors over environmental externalities that are complex and controversial to assess and, particularly, to measure. At the same time, users may face less accountability for their consumption behavior.

2. The Circular Maritime Economy

The crucial role seaports play in global trade and economic development is well documented. As sustainability concerns gained traction, the circular economy emerged as a parallel concept that redefines conventional linear supply chain practices by adding feedback mechanisms. Its principles, namely reduce, reuse, recycle, and remanufacture, align with stated goals by the port industry to minimize its environmental impact, conserve resources, minimize its footprint, and optimize operations. These principles promote a closed-loop system, encouraging seaports to envision their practices and rethink their role in global and local supply chains. The application of circular economy principles is not only about more efficiency in the existing economic system but also about notable changes in supply chains.

The circular economy presents a paradigm shift for seaports, transforming them into actors more actively involved in implementing sustainable principles and promoting resource efficiency. By addressing challenges and seizing opportunities, seaports can contribute to a circular global economy with the expectation of improved resilience and environmental impacts. An alignment between governments, businesses, and stakeholders can facilitate the process, but the nature and extent of such an alignment have not been well defined. Ports and governments are paying attention to the energy transition, or even parts of it, such as hydrogen (flows, infrastructure). Circular challenges are somewhat overshadowed, and the interactions between energy and CE transitions are not fully recognized.

A comprehensive overview of the circular economy, as it applies to maritime container shipping and ports, underlines the main linear and feedback mechanisms particular to the industry. It underlines that there are two separate and interdependent circular systems:

• Maritime shipping ship maintenance, ship sales and charters (reuse), ship conversion (remanufacture), and ship scrapping (recycle) are elements of CE mechanisms. Responsible ship recycling and circular ship design are key fields of action in this area.
• Ports have CE mechanisms, including port maintenance, concessions (reuse), port upgrading (remanufacturing), and port conversion (recycling).

While maritime shipping involves specific CE mechanisms, a focus on ports underlines that they play a dual role in the circular economy:

• Circular ports. Identifying the existing or potential circular processes within a port considering their inputs and outputs. Fundamental inputs to port operations include capital, land, equipment, labor, and energy, all of which can be subject to circular processes. At the minimum, circularity should result in similar output levels even if several inputs are reduced. A core strategy is to establish linkages between existing port users to find commonalities.
• Circular maritime supply chains. Identifying the existing or potential options where a port can develop and expand circular processes within the supply chains it supports. The port can be a site, a facilitator, and an intermediary for circular processes.

The setting of circular economy principles in ports is incited by drivers such as the goal to attract new added value activities in the port area, new technologies allowing for new circular mechanisms, the provision of incentives such as subsidies and tax abatements or inducing compliance to circular principles with rules and regulations about environmental externalities. However, several barriers can hinder the development of a circular economy at ports, such as an organizational structure having a lack of leadership, stakeholders seeing limited benefits from CE activities, acute capital requirements with limited demonstrable returns, land availability issues, and the need for infrastructure supporting circular economy activities such as electric power generation and recycling facilities.

Containerization illustrates a specialized form of circularity since a container can be reused as long as it remains in good condition, requiring regular inspections and maintenance. Empty containers need to be repositioned between locations having a positive inbound trade balance and those with a positive outbound trade balance. At the end of their life cycle of about 15 years, containers can be recycled for their components or remanufactured for other uses, such as for storage sheds and real estate (housing, offices, retail).

American containerized trade with China in the 2010s can be considered an early form of circular maritime supply chains. Incentivized by imbalanced trade and the associated lower container freight rates for China-bound cargo, waste paper and recycled goods such as metals were collected on the US West Coast and loaded into empty containers, preferably 20-footers. Then, containers were carried to China, and the cargo was used as manufacturing inputs. Thus, the contents of many American retail imports from China, including the packaging, were recycled goods. This circular process emerged without any form of planning and was the outcome of market considerations, which should be the most desirable option in implementing circular processes.

3. Ports as Hubs for Material Sourcing

A. Recycling and beyond

The recycling economy differs from the circular economy in that most materials can only be recycled a few times before their quality declines and are no longer reusable. A circular economy aims to keep products and materials in use without degrading their quality or downcycling into lower-valued products. A wide array of recycling, upcycling, and reuse processing techniques are available for different types of materials, products, and waste streams:

• Mechanical recycling involves processing products or materials into secondary raw materials or products by mechanical processes such as sorting, washing, drying, grinding, re-granulating, and compounding. Mechanical recycling does not change the chemical structure of the material, which permits multiple reuse, creating a closed loop. Still, the quality of the component may degrade and can eventually no longer be recyclable.
• Chemical recycling involves processing products or materials by changing their chemical structure and turning them back into substances (even at the molecular level) that can be used as raw materials for manufacturing other products or materials. Chemical recycling technologies include, for example, pyrolysis, gasification, hydrocracking, and depolymerization. The challenge is that chemical recycling may consume large quantities of energy and may require expensive catalysts.

Each technique leads to different decomposition levels of the materials concerned, as exemplified by the available recycling technologies in the life cycle of plastics, the treatment of contaminated dredged material, ship recycling, or the recycling of wind turbines. The associated chemical processes (if any) need to be very precise and flexible, as the input materials can be very diverse. This requires detailed knowledge of the incoming materials and advanced methods to sort out different waste products. Next to recycling, waste material flows can be reduced by simplifying materials and products at the design phase and by designing business models and product designs to make more efficient use of materials.

B. Action fields for material sourcing hub creation

Seaports can transform into hubs for circular materials by adopting comprehensive strategies. They can act as hubs for material recovery and reuse by implementing reverse logistics and encouraging sustainable product design. By salvaging materials from end-of-life products and returning them to value chains, seaports can contribute to a more resource-efficient economy. In this way, seaport ecosystems can manifest as sources of materials and even individual molecules that can form the building blocks for new materials and industry procurement sources. By integrating these aspects and fostering a circular materials ecosystem, seaports can advance circularity, reduce waste, and promote sustainable practices within their operations and the wider community. Several key areas of action can be identified:

• Material flow analysis and mapping. Detailed insights on recycling and reuse flows for a broad array of supply chains (batteries, precious metals, plastics, etc.) and waste products (waste heat, wastewater, etc.) are needed. This requires thoroughly analyzing material flows within and outside the port to understand the types and quantities of imported, exported, and processed materials. Such an exercise should enable the creation of detailed materials flow maps to identify potential circular material opportunities. Some of these circular flows can be organized locally (including the port-city interface), while a more regional and even global flow system needs to be developed for others. Material exchange platforms are essential to material flow analysis and mapping and typically include four components: a material passport, a digital twin, material valuation, and matchmaking. Ports are challenged to develop digital platforms that connect businesses and industries within and around the port to facilitate the exchange and reuse of materials. Some industries may be unaware of material sourcing opportunities. Digital matching platforms ideally allow finding high-value reuse options for materials or (waste) products and unlock the potential of these streams by matching them to their highest-value uses.
• Waste reduction and recycling programs. Relevant stakeholders should implement waste reduction and recycling programs within the port and surrounding areas to minimize landfill waste. At the same time, appropriate infrastructure and incentives should be provided to allow the responsible disposal of materials. For the transition to a circular economy, ports are challenged to close material cycles so that residual flows are given a second life and reused or recycled.
• Circular material sorting and processing facilities. Port ecosystems that want to promote a hub function in material sourcing need to establish dedicated facilities within the port area for sorting, processing, and repurposing various materials. This also involves implementing technologies that enable efficient sorting and processing of materials to extract maximum value from waste streams. Ports can be instrumental in developing circular flows by supporting small-scale demonstration or showcase projects in the port area. Such projects enable testing the technical and economic feasibility of a broad array of material recycling and upcycling techniques. At the same time, such projects are needed to strengthen stakeholder support for circular activities and to gain access to capital to fund a later transition from proof of concept (typically start-ups) to projects of a viable economic scale (scale-up).
• Collaboration, partnerships, and intermediation. To become material-sourcing hubs, ports need to foster a collaborative port ecosystem focused on circularity. Port actors need local businesses, research institutions, government agencies, and non-profit organizations to drive research, innovation, and knowledge sharing in the field of circular materials. At the same time, port authorities, industry associations, and other relevant stakeholders can cooperate to facilitate industries to trade surplus materials, by-products, or waste streams that can be repurposed by others. Inter-firm cooperation through industrial symbiosis is a form of mediation that brings companies together in an innovative collaboration and finds ways to use one’s waste as a raw material for another.
• Circular material policies and incentives. For ports to become effective material-sourcing hubs, the wider port ecosystem should advocate for and implement policies that incentivize businesses to adopt circular practices, such as tax incentives for recycling and material reuse, reduced tariffs for reusing materials, or subsidies for circular technology adoption.
• Education and awareness. Relevant port actors should facilitate and implement awareness campaigns and educational programs to inform stakeholders, including businesses, employees, and the general public, about the benefits of and specific demands related to creating material sourcing hubs as part of a circular economy in a port context. The information provided should be evidence-based to avoid a public backlash if projects are hyped and do not yield according to inflated expectations.
• Circular design and innovation. The port ecosystem should promote and create awareness of product and packaging designs, prioritizing recyclability, reusability, and durability to ensure easier material recovery and reintegration into the economy. This also includes circular supply chain design by supporting businesses that prioritize sourcing materials from recycled content or utilizing reusable materials and by facilitating efficient transportation and logistics to minimize waste and optimize material use.
• Monitoring and reporting. The port ecosystem should be responsible for establishing monitoring mechanisms to track the progress of circular material initiatives, including relevant metrics related to material reuse, recycling rates, land use implications, and environmental impact. Regularly reporting progress to stakeholders enhances awareness and creates transparency. Such an exercise can be part of broader sustainability reporting or be developed separately.

A core challenge remains that few, if any, of these practices have been demonstrated. The value proposition of port circular principles is still to be assessed.

4. Port Land Management

The circular economy in seaports impacts land management and spatial planning by promoting efficient resource use, waste reduction, and sustainable practices. This can lead to optimized land allocation, improved waste management systems, and the integration of recycling and reuse facilities within port areas. Additionally, the circular economy encourages the development of eco-friendly transportation and storage solutions, influencing the layout and design of port infrastructure.

A. Land availability and demand for CE

Land has become a scarce and complex resource for ports to manage. Therefore, it is over the issue of land and its footprint that ports are challenged to address the circular economy as this particular resource is difficult to improve. Land is required for CE activities to develop in ports, but how much space varies on the types of CE activities and future economic scenarios relevant to the port. Some studies in this area indicate that, depending on the scenario, the circular economy as a whole could require up to 40% more space in 2050 than the current linear fossil economy.

The circular economy as a whole could require up to 40% more space in the 2050s than the linear fossil economy of the 2020s.

For CE to be implemented in a seaport context, it is important to create the right conditions in spatial planning policy by paying attention to circular strategies when developing, transforming, and restructuring areas in the port area and its region. This requires coordination and cooperation between relevant stakeholders such as various government departments, managing bodies of ports, and port land users or concessionaries. In many regions, it is considered a challenge to find the necessary space between existing land claims in seaport areas but also in the vicinity of the port (such as in relation to housing, nature, agriculture, and mobility).

Irreversible decisions on land allocation can further complicate the transition to a circular economy. For example, when an industrial estate with a high nuisance level or high environmental impact is given another destination, this decision can jeopardize the reuse of the site for industrial CE activities. Also, the development of an industrial estate of the highest environmental category takes decades due to permitting and licensing processes. Therefore, it is important to reserve the space required for circular activities with a more industrial character in a timely manner and to be careful with repurposing existing industrial estates and brownfields in seaport areas.

To prepare for and accommodate the transition to a circular economy, managing bodies of ports, and local, regional, and national public authorities are challenged to consider the following:

1. Develop a systematic approach to secure the required space for CE developments: Decentralized authorities and managing bodies of ports must develop a regional spatial vision of the circular economy and raw materials, linked to a concrete implementation strategy at the regional level. In line with this, higher government levels must work with other parties at the country or supranational level on a spatial strategy or pathway for a circular economy.
2. Estimate the space required in and around seaport systems under different CE scenarios.
3. Reserve strategic locations in planning terms to avoid irreversible choices that hinder the CE transition. A physical environment that is attractive for circular behavior can contribute to the transition to a circular economy.
4. Plan and develop infrastructure for the circular economy: Circular economy requires timely adjustments in transport and energy network infrastructure and the space required to transport materials, goods, and the required (renewable) energy.

B. The (re)development and (re)use of port sites

From a port (re)development perspective, port sites can be labeled with several different field names, depending on the location and current use, including greenfield, brownfield, blackfield, greyfield and bluefield.

Designating these terms can have regulatory and financial implications in the context of land redevelopment or regeneration.

Greenfield port development in uncontaminated areas is increasingly under pressure due to a lack of greenfield space, competition by potential alternative uses (nature, agriculture, urban), and the availability of other sites that could be reused. Therefore, ports are challenged to consider the redevelopment, regeneration, and reuse of existing port sites. However, these sites are often contaminated. In the past, landfill sites in ports were very common, functioning as buffers or storage areas for waste. While these practices have been replaced by specialized chemical waste treatment facilities, reminders of the old practices can be found in the form of contamination at many port sites.

Non-greenfield land might face major challenges in attracting project developers and investors because of (historical) environmental contamination, even if these lands do (or could) have enormous potential in terms of space for port renewal or the implantation of new companies. Environmental contamination can involve soil penetration of chemicals, asbestos-containing materials, lead-based paints, and hazardous wastes. These locations can be frightening for most developers and business owners due to the fear of expensive environmental liability, high remediation costs, and unsafe conditions for workers.

Still, the redevelopment of port brownfields produces numerous environmental, social, and economic benefits. Today, many of these original port locations have been replaced by newer technology, or have moved to more strategic locations (the so-called port migration). In many cases, seaports have grown away from their original locations (see the ‘Anyport’ model), many times leaving behind abandoned sites, buildings, and equipment. By cleaning up and returning these lands to use, communities can remove dangerous structures and stop or stabilize contamination near waterways. Most seaports were initially developed in or close to an urban core. Port redevelopment presents valuable opportunities for urban regeneration in the form of waterfront redevelopment, and it may catalyze revitalization in the broader community.

Brownfield redevelopment frees space for various uses and creates more available property for sale or lease, providing ports with additional sources of revenue. Besides, redevelopment of previously used sites can help alleviate pressure on undeveloped wetlands and coastal areas, thus protecting important coastal habitats.

Quite a few countries have worked out specific regulatory frameworks in order to facilitate the redevelopment or regeneration of brownfield sites. An example is the so-called brownfield covenants or agreements signed between a public authority on the one hand and the actors of a brownfield project on the other hand, in which the necessary agreements are made about temporal demands and expectations and procedural requirements and expectations. The brownfield covenant makes it possible to work on the concrete redevelopment of the port site or area over a longer period of time within the agreed framework. The responsible government or public agency might also provide a number of financial benefits when concluding a brownfield agreement, such as:

• A specific procedure for expropriating essential land to realize the project.
• An exemption from the normally mandatory provision of financial security on the transfer of contaminated land.
• An exemption from registration duties when purchasing real estate in the context of a brownfield project.
• Public authorities might offer competitive grants to provide funding for environmental assessments, remediation, public education, and economic assistance.
• Financial assistance to fund the necessary cleanup efforts can provide developers with the necessary liability assurance to invest in redeveloping these areas.

Brownfields can also play a role in energy transition in ports.

Energy generation from renewable sources is not affected by contaminated soil, groundwater, or air. When a property with environmental contamination is in various stages of remediation, the land can be used to house solar panels (brightfields) and wind farms (windfields). Thus, brownfields can be reused for renewable energy generation.

Next to greenfield and brownfield port development projects, port sites can also accommodate retrofit projects whereby the equipment, installations, and buildings on an existing site are upgraded to meet contemporary market or sustainability standards. Typical examples include:

• The transition from a conventional container terminal to a fully or semi-automated terminal by replacing manned yard equipment with automated stacking cranes (ASC) and automated guided vehicles (AGV) for horizontal transport.
• The retrofitting of industrial installations to allow a transition from fossil fuels to renewables; to change the feedstock used as input for the production process; or to enable the reuse of waste heat or other byproducts of the production process.
• Existing warehouses and distribution facilities in the port are upgraded by adding additional insulation, changing lighting to LED lights, installing solar panels on the roofs, and replacing diesel-powered equipment such as forklifts with electric equipment.

C. Lifecycle management of port infrastructure

An essential principle of the circular economy involves a commitment to keeping products in use and providing value to the process. Life cycle thinking involves the consideration of the economic and social values of circularity and thinking about design, development, and, crucially, what happens once a structure reaches the end of its life cycle. In this realm, ports are infrastructure-intensive facilities that should develop infrastructures with an extended life cycle that can be repaired, refurbished, and reused.

Lifecycle management of port infrastructure is an important aspect of circular principles.

Embedding circular principles within the design phase of port infrastructure considers flexible port infrastructure design, which allows for upgrades, extensions, and alternative uses when needed. Integrating flexibility concerns in the design of quaywalls and locks is not easy, given that the initial construction and any changes made afterward are typically very expensive. Building infrastructure creates strong path dependency mechanisms since it sets standards and capacity for long periods. Therefore, designing for flexibility in practice might result in building more capacity than the current market (or projections) might anticipate to avoid expensive retrofitting or reconstruction afterward. For instance, designing a sealock larger than the current capacity would justify anticipating the potential future scale increases in vessel sizes. Still, new technologies such as additive manufacturing allow for new opportunities for the construction and maintenance of port terminal facilities, particularly if the materials are sourced from construction recycling materials.

The lifecycle management of port infrastructure also involves sustainable maintenance strategies aimed at reducing the environmental impacts of port operations, enhancing the resilience and performance of port assets, and extending the economic life of the infrastructure. There are different approaches and methods to develop such strategies, depending on the type and condition of the infrastructure, the port’s vision and goals, available data and tools, and stakeholder involvement. Some key considerations for port infrastructure include:

• Port infrastructure maintenance strategies with a focus on minimizing the life cycle cost and greenhouse gas emissions while maximizing the reliability of the infrastructure.
• Evaluate, compare, and improve maintenance strategies by taking into account technical, environmental, and economic aspects. A proactive and preventive maintenance approach considers the uncertainties and complexities of port infrastructure.
• Decision-making and maintenance planning system by integrating data on the technical details of the condition of port infrastructure, a risk-based evaluation of infrastructure performance, and a cost-benefit analysis of risk treatment solutions.

Decisions and strategies concerning the circularity of port infrastructure are among the most costly and risk-prone. If they are successful, the benefits can be substantial, but if not, the sunk costs can create serious financial difficulties for infrastructure managers. When port infrastructure has reached the end of its life cycle for economic or technical reasons, it should be stripped for parts and components, and anything left should be recycled and reused. The challenge remains the cost of recovery and reuse of heavy physical infrastructures.

D. Land concessions

Land for port development is a scarce and valuable resource, making the concessioning of port sites to private companies a primary task for landlord port authorities. A well-designed concession policy allows port authorities to retain some control over the organization and structure of the supply side of the port market while optimizing the use of scarce resources such as land.

Therefore, landlord port authorities can consider the explicit inclusion of circular economy factors when awarding land concessions to private operators:

• When deciding which site to award, port authorities could more explicitly look at the CE quality of the port site. Brownfields might be more expensive to redevelop but often lead to higher spatial quality and site regeneration. Port authorities could also include more stringent guidelines on the circular design of port infrastructure and superstructure, making the concessionaire bear some responsibility for repurposing the site they used near the end of the concession.
• In the awarding or selection phase, the CE quality of the candidate’s bid can constitute a new element in the qualification phase of a port site awarding process. By doing so, possible candidates are rewarded for their current proposals and previous initiatives in other ports or locations in circular activities and operations. There is scope to more explicitly integrate circularity-inspired performance measures in the selection process next to more traditional criteria such as throughput expectations, financial performance, the price bid, and socio-economic impacts in terms of value-added created and employment effects.
• Port authorities should also consider including CE elements in the post-bidding phase, such as by including circularity-inspired clauses that go beyond simply stipulating that the concessionaire will have to make efforts to comply with local, national, and supranational legislation related to CE. Such clauses could, for example, refer to the compulsory use of circularity management reporting or monitoring systems.

5. Energy Management

Circular economy strategies encourage the use of renewable energy sources and the adoption of energy-efficient technologies, which directly impact seaport operations. Energy is crucial in optimizing resource use, material recycling, and minimizing waste. Additionally, energy efficiency measures contribute to the overall sustainability of circular practices by lowering resource consumption during manufacturing and transportation processes in seaport areas.

Ports have a significant role in the convergence of energy and materials transitions. It concerns a twin transition or the transition to a circular and low-carbon society over the various components of the port ecosystem, such as waterways, quays, yards, and hinterland transportation. Renewable energy integration and energy-saving measures can enhance the overall sustainability of seaport activities. However, abundant and low-cost energy sources are fundamental to economic prosperity, particularly in developing economies. There is a high risk that circular principles applied to the maritime sector could increase the cost of energy and, consequently, the cost of transportation.

In the context of seaports, energy management contributes to circularity in several ways, such as:

• Renewable energy integration. Seaports can adopt renewable energy sources such as solar, wind, or tidal power to generate electricity. Integrating these sources into the port’s energy mix reduces reliance on non-renewable energy and lowers the environmental impact.
• Energy efficiency measures. Ports can implement energy-efficient technologies and practices in port operations to help reduce overall energy consumption.
• Waste-to-energy systems. Port ecosystems can explore waste-to-energy systems where waste generated within the port is converted into energy. This supports waste management and contributes to the circular use of resources by extracting value from materials that would otherwise be discarded.
• Digitalization. Deploying digital/data infrastructure and technologies, such as energy management systems and IoT devices, allows ports to monitor and control energy consumption in real time. Digital solutions allow for more informed decision-making and the identification of opportunities for energy optimization.
• Electrification of port equipment. Transitioning from traditional fossil fuel-powered equipment to electric or hybrid alternatives reduces the carbon footprint of port operations. This electrification can extend to various activities, including cranes, trucks, and other machinery used for cargo handling.
• Energy storage solutions. Incorporating energy storage systems, such as using batteries or the transition of green electricity (wind/solar/hydro) to green hydrogen, allows seaports to store excess energy generated during periods of low demand and use it during peak times. This helps balance the energy supply and demand and ensures a more stable and efficient energy use.
• Lifecycle Assessment. A lifecycle assessment of the port’s energy infrastructure is crucial for identifying areas where improvements in terms of energy use can be made.

Energy management also plays a crucial role in recycling and upcycling activities in seaports. The collection and transportation of recyclable materials by seagoing vessels, inland barges, rail, or trucks often involve energy-intensive processes. By optimizing routes, improving fuel efficiency, and transitioning to alternative energy sources, the overall energy footprint associated with the logistics of recyclables can be reduced. A vast amount of energy is required in the sorting and processing stages of recycling facilities. Advanced sorting systems and machinery, and the use of zero- or low-carbon energy sources help to minimize the energy and emission impact of these activities. In some cases, recyclable materials are used as feedstock for waste-to-energy systems, where they are converted into energy through processes like incineration. For these activities, it is essential to maximize the energy yield while minimizing environmental impacts. Finally, manufacturing products using recycled materials also requires energy management throughout the production processes through the use of energy-efficient equipment and renewable energy sources. Regularly monitoring, analyzing, and implementing energy-efficient technologies and practices throughout the recycling supply chains contribute to continuous improvement in recycling operations.

6. Waste Management

Seaports generate significant waste through dredging, construction, industrial activity waste, and vessel-generated waste. Managing wastes at ports has been practiced for centuries with simple disposal practices such as nearby landfills or simply dropping wastes into the ocean. For instance, Monte Testaccio in Rome is an artificial mound almost entirely composed of discarded imported amphorae accumulated during the maritime trade of the Roman Empire over four centuries. Many amphorae could not be reused because there were limited outbound trade flows for the capital city. The current scale of waste-generating activities in port areas forbids such practices, and in the last decades, complex waste management activities have emerged. Adopting CE practices represents the latest evolution in this trend by implementing waste reduction and reuse/recycling programs, leading to decreased environmental emissions and better resource management. It is shifting the focus to closing material loops at the port system level, where waste can be used as a resource in other parts of the value chain.

Waste management in seaports is linked with several activities, including treating contaminated dredge material, recovering and reusing industrial waste heat, waste-reception facilities for vessels, and treatment of waste generated during port operations by port authorities, terminal operators, and other service providers. The way that ports collect and manage waste generated by landside activities or ship calls can lead to high recycling rates and valuable materials finding their way back into the economy. Otherwise, an inefficient system where most waste (recyclable or not) ends in the sea or landfills or is incinerated, with harmful environmental impacts and potentially significant economic losses.

One of the most significant sources of waste in ports results from dredging, which allows the berthing of seagoing vessels of increased size and to keep shipping channels open. For many ports, hundreds of millions of cubic yards of material are dredged annually to maintain access for ships into harbors and waterways. However, of that dredged material, only clean (non-contaminated) material, accounting for less than half of all dredged material, can be used for land reclamation, construction fills, beach reconstruction, topsoil, and habitat creation or restoration. Contaminated dredged material must be stored in specific facilities where it can either be left to naturally be restored over decades (decomposition by bacteria) or be manually and chemically decontaminated.

Waste treatment is critical to circularity in ports. The development of effective port reception facilities (PRF) to collect ship wastes and the establishment of systems that provide incentives for ships to use these facilities are significant elements in a process toward reducing waste discharges and implementing circular principles related to waste management.

Waste generation on seagoing vessels may be harmful when inadequately managed. The annual ship wastes and residues at sea are estimated to exceed 1,2 million cubic meters of oily waste, 1,4 million cubic meters of sewages, 450,000 tons of garbage, 24,000 cubic meters of sludge, and 360,000 cubic meters of bleed-off from scrubbers. The amount and types of waste may vary from one ship category to another. For example, cruise ships are among the highest waste generators. While they comprise only a small percentage of the global shipping industry, it is estimated that around 24% of all waste produced by shipping comes from this sector. At the same time, some geographic areas are more exposed to the accumulation of and impacts from sea-based waste due to their proximity to shipping routes. Two European cases, Malta and the North Sea, with heavy maritime traffic, are good examples of higher geographic exposure compared to other parts of the world, such as the Baltic Sea, the East Mediterranean, the Caribbean Sea, or the North Persian Gulf. For ports, the presence of the essential PRFs and associated processes (i.e., segregation, recycling, etc.) for handling the waste that ships deliver is crucial.

A circular economy approach also emphasizes lowering the wastes generated by seagoing vessels discharged at sea. In the absence of available global data, the precise amount of the waste gap, that is, waste generated on board ships but not delivered at ports or treated onboard, is not known, i.e., wastes at sea might be the outcome of several sources, in Europe alone, and although garbage delivered in ports has increased since the introduction of regional rules for ports reception facilities, a significant delivery gap in waste remains, estimated between 60,000 and 300,000 tonnes, i.e., 7% to 34% of the total to be delivered annually.

With shipping accounting for substantial discharges of wastes and residues at sea, port activities targeting the reduction of discharges of ship-generated waste and cargo residues into the sea are closely linked with protecting the marine environment. Ports have a crucial role to play in achieving this goal. Avoiding dumping any food, domestic, and operational waste by a vessel or disposing of plastics in territorial waters is subject to ports providing the facilities for receiving ship-generated residues and waste. PRFs should meet the disposal needs of ships using the port without causing undue delays. Circularity is advanced by implementing a cost recovery system (e.g., a waste fee), incentivizing ships not to discharge ship-generated waste at sea. Still, addressing the existing “waste gap” goes beyond port responsibilities and demands investments and measures to combat a range of waste resources, thus requiring collective action by additional stakeholders.

The efforts of ports in selecting and managing the waste they collect are linked with the need to implement waste management and develop facilities, technologies, or services to allow continuity to a ship’s waste disposal life cycle. This involves separate perceptions between how waste management from vessels is carried out and the systems and controls implemented in land-generated solid waste management. Since there are differences between land-based and maritime waste management, it is worth effectively segregating the types of waste generated onboard and ashore with the recycling facility. Yet, an on-board and ashore integrated waste management system is essential to avoid a ship-shore interface break. Developing and implementing comprehensive programs where all types of waste and the waste management process are jointly considered might best address the adverse impacts of waste management. This is because implementing the appropriate waste management schemes would enable avoiding abrupt breaks in the life cycle of waste streams sorted and collected on-board and their transfer ashore.

An integrated approach takes into account five over-arching principles for waste management:

• Waste management hierarchy. The aim is for waste materials to be reused, recycled, recovered, or used as an energy source rather than to prevent waste generation and reduce its harmfulness by safe disposal. The goal is to identify the most harmful or valuable wastes and prioritize the handling, disposal, and reuse accordingly.
• Self-sufficiency in the community along with establishing an integrated and adequate network of waste disposal facilities.
• Implementing the best available techniques. Costs associated with circularity are reduced as much as possible and in the most economically efficient way.
• Proximity. Wastes should be disposed of as close to the source as possible.
• Extended Producer Responsibility. Economic operators, particularly product manufacturers, must be involved in extending the life cycle of substances, components, and products from their production.

Regulatory initiatives at international and regional levels support a circular approach in handling the generated waste, as they provide specific long-term obligations for ports that establish the right conditions for receiving and treating the reception of wastes. The International Maritime Organisation (IMO) Convention for the Prevention of Pollution from Ships (MARPOL 73/78) has addressed the delivery of ship-generated waste and cargo residues via initiatives promoting PRF availability and enhancing suitability. The requirements that limit the types of waste discharged into the marine environment have been adopted as part of Annex V of the convention, which sets restrictions on handling waste, including all food, domestic, and operational waste.

An example of the measures endorsed at a regional level concerns the European Union (EU), where institutions have adopted and regularly reform directives that aim to enhance the presence of effective PRF in European ports. This directive applies only to ship operations in EU ports, addressing in detail the legal, financial, and practical responsibilities of the different operators involved in delivering ship-generated waste and cargo residues.

7. Strategies for the Circular Economy in Ports

Implementing CE strategies requires the involvement and commitment of many stakeholders and demonstrable benefits. It also involves social and organizational changes supported by economic and legal tools.

A. Path creation toward circularity

The specific challenges brought by CE for ports in the fields of material sourcing, land management, energy management, and waste management were discussed in the previous sections. These challenges include knowing the contribution of a particular economic activity, such as a port service provision, to the environment, equipping the labor force with the relevant skills, raising awareness, and increasing the capacity of involved business entities, modifying linear economic systems, developing and investing in new business models, changing behavior; and relationships between consumer and producer liability regimes, pricing goods and services to reflect full costs and set up policies that promote circular economy.

From a strategic perspective, it is important to acknowledge that circularity in ports is to be perceived as a long-term transition with path dependency mechanisms. This implies that a successful circular transition is a step-by-step process in which small-scale opportunities for closing material flow cycles are identified and seized (for example, two companies in the port area linking waste streams), opening up opportunities for new and larger projects or initiatives. It also underlines the risks of hyping the potential of circularity with inflated expectations. While port authorities and other stakeholders might set large-scale, long-term ambitions regarding circularity as part of strategic planning processes, practical implications often involve a growth path from isolated circular initiatives involving only a few actors to more integrated port-wide plans and projects.

Circularity in ports can only materialize when acting entrepreneurially. The existing technological, economic, and governance-related knowledge and know-how and the relationships and interactions between actors in the port community are the starting point. Such an entrepreneurial approach is expected to eventually generate multiple ‘small wins’ that have the potential to accumulate in a much more profound circular transition in the port. In that sense, a port will have to go through a transitional stage before growing into a truly circular port in the longer term.

Integrating circularity into seaport planning involves designing and operating seaports with sustainability and resource efficiency in mind. In general, CE activities need to develop at three different levels:

• Micro-level. Focus on improving the environmental performance of individual companies involved in port activities by reducing resource consumption and pollution discharges or designing more environmentally friendly services.
• Meso-level. Focus on networks that improve regional systems and environmental protection, energy cascading, exchanging by-products, recycling waste, and, when possible, sharing infrastructures.
• Macro-level. Focus on port-related communities (i.e., regions, cities, municipalities, or provinces) that might facilitate the development of a sustainable port services provision and use system.

Existing CE initiatives at ports already range from the micro-level, such as reusing waste streams within a single port or service provider, to the meso-level, such as industrial symbiosis between two or more companies at a port, to interregional port-industry networks for the exchange of secondary resources at the macro-level (e.g. the Bioport of Europe project of the Port of Rotterdam). The initiatives have varied from short-term demonstration projects (see, e.g. the Port of Antwerp Sustainability Strategy) to more innovation and optimization-focused medium-term initiatives (see e.g. the Biopark Terneuzen project of the Port of Zeeland) to long-term vision strategies.

B. A system thinking approach

Integrating circularity in seaport planning and operations demands a systems thinking approach.

Port authorities and port-related stakeholders should consider the interconnectedness and interdependence of various elements within a system when addressing challenges related to the path toward circular processes in ports. To consider the environmental, social, and economic aspects of circularity in ports holistically, system thinking also requires understanding the interactions and interdependence of various elements within the system, such as materials, energy, technology, land, governance, and human behavior. Changes in one part of the system can have ripple effects throughout the entire system over time. For circularity to gain traction in ports, all actors involved should gain an understanding of the dynamic nature of the system, thereby recognizing that it evolves and adapts over time and should be able to adapt to changing conditions and uncertainties, namely through resilience.

Synchronism considerations are part of the system thinking approach. Not all elements within the system will develop at the same speed, leading to time lags and bottlenecks in the development of ports towards more circularity. For example, a lack of funding, scarcity of land, limited supply of material flows for recycling, non-optimal governance arrangements, or constraining regulatory frameworks are some of the reasons that can stall the development of a circular project in a port. By adopting a systems thinking approach in circularity, stakeholders can develop more effective strategies and interventions that address the complexity and interconnectedness inherent in sustainable and circular practices.

C. Self-assessment and monitoring

Port ecosystems should engage in circular economy self-assessment. Ports are challenged to assess the current operations of the seaport to identify areas where circularity principles can be applied. This may involve thoroughly analyzing the materials and resources flowing through the port, waste generation, and energy consumption. The setting up of a port-based material exchange platform can be helpful in achieving this, but other initiatives to improve transparency on flows, projects, and plans in the CE context are welcomed.

Performance measurement and monitoring also play a key role in supporting the circular transition in ports. In view of assessing the circular port efficiency and port effectiveness, key performance indicators (KPIs) can be developed and implemented to measure and follow up on circular economy aspects in ports. Implementing performance metrics also helps track the progress of circularity initiatives within the seaport. Some port authorities (such as Copenhagen Malmo Port) have already developed monitoring practices in this field, while broader monitoring exercises have been designed recently, such as the Circular Port Monitor. This monitor provides a concrete framework of 12 indicators tracking the progress towards a circular port. It provides port authorities with a monitoring system of the progress of and performance towards circularity and allows the formulation of the next steps for the gradual advancement of circularity ambitions. Still, monitoring progress toward circular goals is at an early stage of documentation, exploration, and implementation.

D. The governance of circularity in ports

Implementing circular principles in ports requires the consideration of a series of governance challenges:

• Intermediaries for configuring, brokering, and facilitating circular transition efforts. Intermediation helps to balance the many different objectives and efforts in the complex network of port-related actors and stakeholders. A wide array of public and public-private organizations can be instrumental in community building and leadership toward circular transition.
• The role of the port managing entity. Port authorities play a central role as active community builders, engaging policymakers across different policy areas and levels of governance, as well as various stakeholders in the circular port transition. Port governance settings have to be aligned to make it possible to fully benefit from the port’s managing entity’s position between actors and networks so that the port authority engages as an intermediary in the port’s circular transition and is a leader in building-related communities with the port ecosystem. Port authorities might advance processes reducing, incentivizing, and supporting waste reduction and high-quality separation of generated waste, enabling industrial symbiosis, facilitating the clustering of activities to prevent by-products from becoming wastes, advancing new business models, and encouraging wider and better consumer choices. While they aim to decarbonize their footprint in the energy transition process, port authorities can also stimulate emission reductions of the main emitters. Within the wider port area and to benefit the wider economy and community, port authorities can be the facilitator, enabler, developer, and integrator of renewable energy streams and supply chains and stimulate energy transition initiatives in the port.
• Community building and collaboration enable the collaborative resolution of common issues, the development of case studies that can act as blueprints to accelerate the take-up of initiatives, the realization of the essential incremental phases, and any (de)regulatory needs and the required transitional phases. It can also bring CE-related projects to reality (i.e., not being overambitious) and, not least, increase investments in advancing circularity. As circular projects are not necessarily interconnected, and their contribution might not be entirely visible and understandable by all involved in the port ecosystem, the level of voluntary investments by individual entities might be otherwise low. As cluster and community managers, port authorities have a specific role in engaging and stimulating collaboration with local governments, environmental organizations, and businesses to exchange best practices, share resources, and align goals for CE in ports. Through cluster governance of the circular port transition, the port authority might even assume leadership in aspects that conventionally were outside its jurisdiction, such as various strategies to monitor and improve circular performance, setting up material flow analysis tools, and facilitating relations with its surrounding urban areas on circular port issues. The leadership of the port authorities creates conditions for increased levels of investments in advancing port circularity.

E. Focus areas

Implementing port circular processes can particularly focus on the following approaches:

• A focus on resource efficiency. Port infrastructure and facilities need to be planned, designed, and operated to minimize resource consumption, such as energy, water, and raw materials. This includes, for example, energy-efficient lighting, renewable energy sources, and water recycling systems.
• A focus on sustainable transportation. This does not only involve using low-emission and energy-efficient transportation methods, such as electric or hybrid vehicles, for cargo handling and transport. It also assumes a sustainable modal split in the connection to the hinterland.
• Digitalization and smart technologies. Digital technologies and data analytics are not only important to optimize port operations. They can also help improve resource allocation, reduce energy consumption, provide transparency in material flows, and enhance overall circular efficiency.
• Circular business models. Port authorities can encourage port-related businesses to adopt circular business models, where products and materials are designed for reuse, refurbishment, or recycling.
• Research and innovation. Port authorities can support research and innovation initiatives to find new circular solutions, technologies, and practices for seaports.
• Public awareness and education. Educating port stakeholders and the general public about the importance of circularity in seaports is key to making the transition feasible and fostering a sense of responsibility and sustainability within the community.
• Regulatory compliance. Port authorities should ensure the port complies with relevant environmental and sustainability regulations and standards. At the same time, the broader port community should provide input and feedback about the regulatory environment, such as when complex and inconsistent regulations complicate the CE transition in the port.
• Financial considerations. The circular transition involves significant finance and investment needs. Port authorities, in cooperation with relevant stakeholders, should carefully estimate and assess the upfront investments needed for circular projects and the associated return on investment. Also, the link with sustainable finance is an important consideration when engaging in circular projects in a port context.

The previous sections discussed other focus areas in the fields of material sourcing, land management, energy management, and waste management.

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Related Topics

• Chapter 1.2 Ports and Maritime Supply Chains
• Chapter 1.4 Ports and Distribution Networks
• Chapter 2.5 Green Shipping and Supply Chain Management
• Chapter 2.6 Ports and Energy Transition
• Chapter 6.4 Port Resilience
• Chapter 7.4 Port-City Relationships

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Acknowledgment: This chapter has been made possible with the support of Circular Flanders. However, the content in this chapter reflects the personal inputs of the authors about the subject supported by relevant sources and inputs. Further information and background material on circularity in ports can be found in the circular ports section of the website of Circular Flanders.

References and further reading

• Alix, Y., Mat, N., Cerceau, J. (eds.) (2015). Economie circulaire et écosystèmes portuaires, Editions EMS: Cormelles-le-Royal, 423 p.
• Barona, J., Ballini, F., Canepa, M. (2023). Circular developments of maritime industrial ports in Europe: a semi-systematic review of the current situation. Journal of Shipping and Trade, 8(1).
• Bjerkan, K. Y., Hansen, L., Steen, M. (2021). Towards sustainability in the port sector: The role of intermediation in transition work. Environmental Innovation and Societal Transitions, 40, 296-314.
• Carpenter, A., Lozano, R., Sammalisto, K. and Astner, L. (2018). Securing a port’s future through Circular Economy: Experiences from the Port of Gävle in contributing to sustainability, Marine Pollution Bulletin, 128, 539-547.
• CE Delft / EMSA (2017). The Management of  Ship-Generated Waste On-board Ships, Lisbon: EMSA. 
• Circular Ports (2024), website hosted by Circular Flanders, https://circularports.vlaanderen-circulair.be/
• Courtens, F. M., Haezendonck, E., Dooms, M., Verbeke, A. (2023). Accelerating the circular economy transition process for gateway ports: The case of the Port of Zeebrugge. Maritime Transport Research, 4, 100088.
• de Langen, P. W., Sornn-Friese, H., Hallworth, J. (2020). The role of port development companies in transitioning the port business ecosystem; the case of port of Amsterdam’s circular activities. Sustainability, 12(11), 4397.
• Dellink, R. (2020). The consequences of a more resource efficient and circular economy for international trade patterns: A modelling assessment, OECD Environment Working Papers No. 165
• European Commission, 2018. Impact Assessment proposal for a Directive on port reception facilities for the delivery of waste from ships, COM(2018) 33 final. Brussels: European Commission..
• Faut, L., Soyeur, F., Haezendonck, E., Dooms, M., de Langen, P. W. (2023). Ensuring circular strategy implementation: The development of circular economy indicators for ports. Maritime Transport Research, 4, 100087.
• GESAMP (2021). “Sea-based sources of marine litter”, (Gilardi, K., ed.) (IMO/FAO/UNESCO-IOC/UNIDO/ WMO/IAEA/UN/UNEP/UNDP/ISA Joint Group of Experts on the Scientific Aspects of Marine Environmental Protection). Rep. Stud. GESAMP No. 108. 
• Haezendonck, E., Van den Berghe, K. (2020). Patterns of circular transition: What is the circular economy maturity of Belgian ports?. Sustainability, 12(21), 9269.
• Wille, E., Tempst, W., Hill, A., Van Cauwelaert, F. (2023). A View on Port Area Regeneration in the Flanders Region (BE), Circular Flanders/ OVAM, 5 June 2023