Dimitrios V. Lyridis, John M. Prousalidis, Anna-Maria Lekka, Vassilis Georgiou, Lambros Nakos
IMAGE LICENSED BY INGRAM PUBLISHING
The article presents the proteus plan, a holistic approach towards the transformation of ports into a sustainable energy hub encompassing cutting-edge smart grid technologies. More specifically, the Proteus plan, which has been developed by an interdisciplinary scientific team (the Proteus team) comprising maritime transport engineers, naval architects, and marine engineers, as well as electrical and computer engineers, aims at a smart port implementation of the integration of a series of actions, such as:
Within this context, the main challenges raised by the smart decarbonized electrification of maritime transportation are discussed.
The maritime industry, following the International Maritime Organization (IMO) and European Union (EU) directives toward minimizing atmospheric emissions of ships, has been focused on designing and building greener ships or greening existing ones via alternate retrofitting techniques. Furthering this concept, modern ports playing a key role in the transportation chain are also facing similar challenges in terms of providing innovative services of superior quality without adverse environmental and societal impact. These challenges have increased at least in the EU by the advent of the so-called fit-for-55% package of directives, currently under consultation aiming at accelerating the pavement toward complete atmospheric neutralization.
To this end, all ports would reform their strategic priorities, being transformed into smart energy hubs where sustainable and smart electric energy systems tend to predominate. In particular, the port facilities and services related to this target include the installation, operation, and management of systems like ship-to-shore interconnection, charging of battery-based ships, safer power supply, RESs, port lighting, cargo-handling cranes, and energy storage systems (ESSs).
This article concerns a discussion of the sustainable growth reformation of ports in alignment to green shipping demands, on the one hand, and the smart grid concept on the other. This combination consists a holistic approach of the port energy transformation, the so-called Proteus plan, which has been developed by an interdisciplinary scientific team (the Proteus team) comprising maritime transport engineers, naval architects, and marine engineers, as well as electrical and computer engineers. Within this context, we show that it is of major importance to design and develop a centralized supervisory EMS of a supervisory control and data acquisition (SCADA)-type in the port area that can integrate, monitor, and control all available energy sources (RESs, grid supply, batteries), as well as all loads served, which comprise ships in cold-ironing mode, battery ships in charging mode, cargo-handling equipment, refrigerating reefers, etc. In this way, all energy transactions can be performed in an optimum manner from the techno-economical point of view. For instance, energy can be stored from RESs or from the grid when the latter provides it in low price, or even from cranes operating in regenerative mode, and provided to loads and consumers upon demand.
Within the framework of greener shipping established by IMO resolutions, modern ports, being transportation hubs, are confronted with significant challenges in terms of providing innovative services of superior quality and high financial, environmental, and societal impact. To this end, all ports would resynthesize their master plan, according to which they are subjected to a transformation into smart energy hubs where electrification plays a key role. In particular, the port clients subject to penetration and sophisticated management of electric energy are:
the characteristics of which are discussed next, highlighting the important role of a central power management system (PMS) supervising all energy transactions in the port jurisdiction.
Ship-to-shore power interconnection (Figure 1) or alternate maritime power is one of the most appealing ways of eliminating the atmospheric pollution (and noise) produced by ships being at berth as their engines are shut-down, while they are supplied with electric energy from the National Grid via the appropriate port infrastructure (Figure 2). The interconnection is recommended to comply with International Electrotechnical Commission/International Organization for Standardization/IEEE 80005 series of standards, namely -1, -2, and -3, while it comprises three distinct subsystems (Figure 2):
Figure 1. Ship-to-shore interconnection scheme (the red lines refer to three-phase flexible power cable connections, while the black line refers to the flexible earthing connections).
An extension of this interconnection type consists in charging battery-driven ships via shore power facilities. Vessels with electric energy storage units (batteries, supercapacitors, etc.) and consecutively with electric propulsion systems, have become quite popular in the last decade as they have been proven both cost-effective and environmentally friendly. These ships have been successfully used for short-sea shipping applications in Northern Europe—e.g., in Norway, Denmark, and Sweden—while some feasibility studies have been performed for Greece where, due to the Aegean Archipelagos, there is a plethora of short-sea itineraries served by shuttle ferries. According to these studies, the investment in an electric transformation of a significant number of such vessels is worthwhile both cost-wise and environmentally.
Furthermore, the same infrastructure utilized for shore-to-ship can be exploited for the reverse power flow: i.e., from the ship to the shore grid. This “reverse cold ironing†can be used in the case of emergencies, such as environmental disasters, but since it can be treated as an energy transaction between the ship and the port it can be exploited in many ways. Thus, in certain cases it might be more beneficial from an environmental and economical point of view for this approach, with a typical example being the noninterconnected islands, the power of which in most cases is strongly dependent on oil, with all its subsequent side-effects (in terms of cost and pollution). In such a case, it has been proven appealing from many points of view to procure electric energy from ships, the electric power of which is based on greener fuels, like liquified natural gas.
One of the most advantageous characteristics of reefers is that they are able to keep their thermal condition almost constant for fairly long intervals, on the order of 6–12 h, even if there is no power supply, which provides significant freedom in controlling the energy supply to them. Thus, they can be supplied on an intermittent basis according to an optimized operation scenario of the entire energy system of the port, as this is processed by the corresponding EMS. As already hinted, long intervals without power supply have no adverse impact upon the internal temperature conditions of the reefer and, consequently, to its content as well.
Modern energy-saving lighting devices, especially those based mainly on LED technology, provide significant reductions in energy demands (in terms of kilowatts) while offering equivalent levels of luminance (Figure 2). Of course, it is well known that LED light devices introduce harmonic distortion problems, which must be taken into consideration.
Figure 2. Luminance of the Kyllini port (LED lights have been placed only in the fishing docks).
Cranes are extensively used for cargo handling in container ships and car carriers. The energy profile of one port crane during operation is shown in Figure 3(a). As can be seen, a most critical issue is the negative power during lifting down of a load that corresponds to the regenerative braking of the driving motor. This regenerated amount of power can either be stored to battery systems of the port or supplied to ships in cold-ironing mode, or even supplied back to the main grid via the port distribution network. Moreover, what is also important to note is that due to this regenerative power, the mean power demand during the duty cycle of the crane is significantly lower than its peak demand. This is further reinforced when a set of cranes is examined. For instance, in Figure 3(b) the power demands during the combined operation of seven cranes is shown; the mean power demand is less than 30% of the maximum peak demand noted, which is something that should be taken into consideration by the EMS of the port grid.
Figure 3. (a) Operating profile (two full cycles of operation) of one single port crane. (b) Total power demand of seven cranes operating concurrently; the mean power demand is in blue.
RESs, like photovoltaic units (PVs) or wind generators (WGs), produce green energy. Hence, taking into account meteorological data, clusters of PVs and small-scale WGs can be deployed in locations available within the port jurisdiction. Moreover, based on economical criteria, the green energy produced can be stored in energy storage units or distributed to the port consumers or even sold to the main grid.
The modern services offered in the port jurisdiction could include parking stations for electric or hybrid-electric vehicles:
The battery units installed in the port jurisdiction can serve the following two-fold goal:
1) Provide energy buffering, i.e. storing electric energy, which is:
2) Facilitate energy bunkering, i.e., electric energy is provided to battery-driven
ships, such as short-sea shuttle ferries. This bunkering can be performed either via:
Furthering the aforementioned concept, all energy storage units installed onshore or onboard ships at berth could service providing storage on demand, provided that this mutually beneficial for all parties involved.
The energy transactions of all electrical subsystems described previously are figuratively depicted in Figure 4. Considering that some of these transactions (e.g., those between the shore grid and the ESSs or the cranes or even the interconnection with the ships) follow the trends of smart microgrids and are bidirectional (Figure 5) ports via their electrified facilities, and can be transformed into energy hubs buying and selling electric energy in bulk. The next step is that all energy sources in the port area, including vessels (with batteries) at berth, battery stacks, and RESs can store or provide energy upon demand. Within this framework, energy is not well located in certain providers but is rather distributed throughout an energy cloud with which transactions can be bidirectional too.
Figure 4. Overview of electric energy transactions within a port.
Figure 5. Integrating electric energy transactions within the port with its PMS.
The PMS of the port is to have an overall supervisory monitoring and control of the energy transactions in the port network (as depicted in Figure 5), remote-control of energy flow, protection, and visualized inspection of critical operating parameters, along with automatic meter reading, meter data management, and asset management for operation, maintenance, and billing purposes. Moreover, the SCADA-type PMS must have capabilities of providing energy to all loads by all available sources in an optimized manner, so that the ultimate target, i.e., the minimized atmospheric pollution by any thermal energy source in the port area, is achieved. To this end, the PMS should be comprised of the following components:
To this end, efficient algorithms for global optimized operation have already been developed. For instance, the port authority acts as the manager and all energy sources and loads are considered to be agents. According to this “win–win†cooperation scheme, the operation scheduling of each agent, as well as the electricity price for the energy transaction between each agent and the port, are finalized after a series of iterative negotiations between them.
Taking into account the aforementioned development perspectives of the ports, the following courses of action can be taken by the port authorities:
Within the context of port energy transformation, the electric network operators need to take some initiatives, in parallel. Thus, the Hellenic Distribution Network Operator has identified the challenge of the energy transformation of ports within the context of green shipping and, via the assistance of the Proteus team, has established a roadmap toward this end (Figure 6).
Figure 6. The roadmap of network operators to support port energy transformation. ONS: onshore power system; RAE: Regulating Authority of Energy.
The main pillars of this roadmap are as follows:
In this section, an effort is made to outline the role of the ports and, consequently, the ships within the electricity market according to the Proteus energy transformation plan as mapped versus the options offered by the directive 2019/944/EU. The latter establishes common rules for the generation, transmission, distribution, energy storage, and supply of electricity, together with consumer protection provisions, with a view to creating truly integrated competitive, consumer- centered, flexible, fair, and transparent electricity markets in the EU. First, the necessary terms are explained so that the operating schemes discussed are more comprehensible.
An aggregator is a natural or legal person who combines multiple customer loads or generated electricity for sale, purchase, or auction in any electricity market. The aggregators act as intermediaries in the electricity market. Independent aggregator means a market participant engaged in aggregation who is not affiliated to the customer’s supplier.
A closed distribution network operator (CDNO) is where a closed distribution system is used to ensure the optimal efficiency of an integrated supply that requires specific operational standards, or where a closed distribution system is maintained primarily for the use of the owner of the system. It should be possible to exempt the DSO from obligations that would constitute an unnecessary administrative burden because of the particular nature of the relationship between the DSO and the system users. Industrial sites, commercial sites, or shared services sites—such as train station buildings, airports, hospitals, large camping sites with integrated facilities, and chemical industry sites—can include closed distribution systems because of the specialized nature of their operations.
An active customer is a final customer, or a group of jointly acting final customers, who consumes or stores electricity generated within its premises located within confined boundaries or, where permitted by a member state, within other premises, or who sells self-generated electricity or participates in flexibility or energy-efficiency schemes, provided that those activities do not constitute its primary commercial or professional activity.
An energy community is a legal entity comprising natural persons, local authorities, including municipalities or small enterprises, that has for its primary purpose to provide environmental, economic, or social community benefits to its members or shareholders or to the local areas where it operates, rather than to generate financial profits. Moreover, it may engage in generation, including from renewable sources, distribution, supply, consumption, aggregation, energy storage, energy efficiency services, or charging services for electric vehicles or provide other energy services to its members or shareholders.
Based on the fundamental definitions of the 2019/944/EU directive, the following alternative schemes have been identified as possible operating models of ports and ships in the electricity market in view of their extensive reformation via electrification.
According to this operating model (Figure 7), the port operates as a CDNO; hence, the port is fully responsible for the reliable and resilient distribution of electric energy into the zone of its jurisdiction. Thus, all energy providers or suppliers inject their energy to the point of common coupling (PCC) of the port, which in turn dispatches it to the ships as well as to other customers served at the port energy terminals. In this operating scheme, the port cannot be an energy provider or producer (hence it cannot own or manage any power sources).
Figure 7. The first alternative operating scheme of ports and ships in the electric energy market.
On the other hand, the ships are treated as active customers who participate in the electricity market either directly or as a member of one or more aggregators; the latter scheme, i.e., being members of an aggregator entity, could be proven even more beneficial for them in terms of pricing, as the aggregator can negotiate for large amounts of energy.
In the second operating scheme (Figure 8), the port once again operates as a CDNO, and hence, it cannot be an energy provider or producer (i.e., it cannot manage any power sources including RES’s and/or energy storage units), at least directly. However, it is possible that another body related to the port (e.g., a subsidiary company) can be one of the energy providers. This can be done provided that the members of the board of this electric company are not the same executives as those with the port authority.
Figure 8. The second alternative operating scheme of ports and ships in the electric energy market.
The ships are treated, once again, as active customers who participate in the electricity market either directly or as members of an aggregator, and they can negotiate with all energy providers, including the one related to the port authority.
Like the first model, this one is most favorable for big-sized ports, where the port authority is strongly interested in being a key player in the energy market. From the ship-side point of view, the electric company of the port could be treated as a last-resort power provider preferred, for instance, by ships visiting the port rather infrequently, and hence not interested in attaining the best available price of the market.
This third alternative model is fairly different from the previous two. In this case (Figure 9), the port along with the ships can comprise an energy community; both the port and the ships can be active customers too. The energy community entity can be engaged in all electric market activities, as it can own RESs and/or energy storage units, as well as serve other members of this very same community, namely the ships at berth, etc.
Figure 9. The third alternative operating scheme of ports and ships in the electric energy market.
This operating model can be applicable in small-sized ports with a limited number of visiting ships. In this case, the ship-owning companies and the port authorities can both be small enterprises having convergent if not common benefits by being partners in the same energy community.
The Proteus plan, as outlined above, has already been implemented in a number of ports within the framework of the following European projects:
According to the roadmap, at the initial stage of implementation there are a number of technical issues that need to be considered, studied thoroughly, and treated properly. Two of them are discussed below.
First is imbalance between power supply and demand. It is probable that the power demands of the ships at berth might not be met by the grid and the port network. Considering that these power demands can correspond to huge energy amounts, this situation can provoke several adverse phenomena, like voltage and/or frequency stability problems to the entire grid. The solution could consist of exploiting flexibility in adjusting power demands by the ships in combination with efficient energy dispatching by the PMS of the port grid.
Second are power quality problems. Considering the equipment related to the port reformation mentioned above, there are a number of power quality phenomena engaged, such as:
This article presents the Proteus plan, a holistic approach toward the transformation of ports into sustainable and smart energy hubs encompassing cutting-edge smart grid technologies. Thus, we show that energy reformation of ports toward decarbonization via electrification necessitates the coordinated activities of a number of stakeholders and beneficiaries, like port authorities, electric grid authorities, and ship owners. The numerous emerging challenges comprise technical and regulatory aspects but they can eventually be treated.
We express gratitude to the following institutions: Climate Infrastructure and Environment Executive Agency of the European Union (EU), for their financial support on implementing the Proteus plan in a great number of European ports through the Connecting Europe Facilities instrument; Hellenic Distribution Network Operator, Regulating Authority of Energy, for the continuous support to port energy transformation via electrification; European Commission agencies (General Directorate of Transport of the EU, General Directorate of Energy of the EU, European Maritime Safety Agency of the EU), for the fruitful discussions on smart and sustainable ports.
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Dimitrios V. Lyridis (dsvlr@mail.ntua.gr) is an associate professor in the School of Naval Architecture and Marine Engineering and Director of the Laboratory for Maritime Transport in the National Technical University of Athens, 15780 Athens, Greece.
John M. Prousalidis (jprousal@naval.ntua.gr) is a professor with the School of Naval Architecture and Marine Engineering and Director of the Laboratory of Marine Engineering at the National Technical University of Athens, 15780 Athens, Greece.
Anna-Maria Lekka (alekka@gatesltd.gr) is a transport engineer and the manager of Gates Ltd., 14121 Athens, Greece.
Vassilis Georgiou (vgeorgiou@protasis.net.gr) is an electrical engineer and the managing director of Protasis SA, 15231 Athens, Greece.
Lambros Nakos (l.nakos@hydrus-eng.com) is a naval architect and marine engineer and the managing director of Hydrus-Group SA, 15343 Athens, Greece.
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