Electric marine fleet management method and system

Abstract

A method is provided for dispatching a fleet of electrified vessels (200) for harbour operations. The method comprises receiving a schedule of tasks (118) to be executed by the fleet, monitoring (120, 122) the vessels (200) and their batteries, as well as an availability of at least one battery charger. The method further comprises determining (126) an amount of time and energy required for the vessels (200) to complete the tasks, and then assigning (128) each task to one of the vessels (200) based on all input data. The method further comprises determining (130) a schedule of battery charging events for the vessels (200). The task assignment (128) and the schedule of charging events are designed to maximise a total number of tasks executed by the fleet in a predetermined period.

Description

[0001] ELECTRIC MARINE FLEET MANAGEMENT METHOD AND SYSTEM

[0002] Field of the Invention

[0003] This invention relates to a method of dispatching a fleet of electrified vessels for harbour operations, considering task energy demands and vessel charging needs.

[0004] Background of the Invention

[0005] Decarbonisation of the shipping industry is becoming increasingly prominent as the world seeks to reduce greenhouse gas emissions. An aspect of this decarbonisation relates to the electrification of support vessels in a port, for example, a fleet of tugs.

[0006] Currently, tugs are usually powered by diesel fuel. Diesel has been used in this industry for decades and, as a result, technology in this field has progressed to the point where any given tug can perform harbour operations for an entire shift without the need to refuel. In other words, for a given shift, a tug has more than enough fuel on board to meet the energy demands required to complete all tasks during a shift.

[0007] At the time of writing, electrification of vessels is a nascent technology and as such electrified tugs do not have equivalent energy potential stored on board as their diesel counterparts. Therefore, consideration needs to be made regarding the optimisation of fleet operations.

[0008] A challenge faced by harbours is managing a fleet of a limited number of vessels to perform harbour tasks with a limited number of charging facilities to resupply the vessels with charge.

[0009] It is against this background that the present invention resides. Summary of the Invention

[0010] According to an aspect of the invention, a method is provided for dispatching a fleet of electrified vessels for harbour operations. The method comprises receiving a schedule of tasks to be executed by the fleet, the schedule of tasks comprising a location and a task description for each task. The method further comprises monitoring a current state of charge of a battery of each vessel in the fleet, a location of each vessel in the fleet, and an availability of at least one battery charger disposed to supply charge to the batteries of the vessels. Further, the method comprises processing the incoming data by determining, based on the task description, an amount of time and an amount of energy required for the vessels to complete the tasks in the schedule of tasks. The processing further comprises assigning each task to one of the vessels based on the current state of charge of the battery of said vessel and based on the amount of time and the amount of energy required for said vessel to complete the task, and determining a schedule of battery charging events for the vessels and the at least one vessel battery charger based on the current state of charge of the battery of said vessel and the tasks assigned to each vessel. The assigning of each task and the determining the schedule of charging events comprises maximising a total number of tasks executed by the fleet in a predetermined period. Finally, the method according to the invention comprises dispatching individual instructions to the vessels of the fleet for completion of the tasks on the schedule of tasks.

[0011] With the method according to the invention, wait time between harbour operation tasks is reduced and the vessels are used more efficiently, taking into account not just their location relative to the tasks to be performed, but also the need and possibility to charge the vessel batteries that deliver the power to perform such tasks. The invention, therewith provides an integrated approach wherein both the vessels and the available battery chargers are put to optimal use, in accordance with their capacities. Consequently, the total number of harbour operation tasks that the fleet is able to perform per day is increased. The benefit of this is efficient management of harbour operations while operating within the limitations of an electrified, zero carbon emission tug fleet.

[0012] By monitoring the state of charge of each vessel and assigning tasks and charge events based on the amount of energy required for said vessel to complete a task, it is made possible to assign the tasks in such a way that the full battery capacity of the vessels is used efficiently, leading to fewer charging events and less travel to and from the battery chargers. As a result, the energy spent by any given vessel travelling between harbour operation tasks and battery chargers is reduced, and the amount of energy put to use for fulfilling such tasks is increased.

[0013] The assigning of each task and / or the determining the schedule of charging events may comprise minimising vessel travel distance. The vessels not only travel while performing one of the harbour operation task, but also when moving from one task to another, and when moving to and from one of the battery chargers to charge their batteries. Vessel travel distance can be minimised by assigning tasks to vessels that are located close to the task location or will be close to the task location at the point in time when the task needs to be performed. Vessel travel distance may be reduced further by ensuring that a subsequent task' s start location is nearby the previous task' s finish location. By minimising the total vessel travel, not just for a single task, but also between multiple tasks and charging events, the total amount of time and energy used by the vessels is minimised and the total number of tasks executed by the fleet is maximised.

[0014] The assigning of each task and / or the determining the schedule of charging events may comprise minimising vessel idle time.

[0015] Avoiding vessels to be inactive while waiting for a new task to be performed or an available battery charger to be charged by, may further promote the efficient use of the complete fleet of vessels and increase the total number of tasks executed by the fleet.

[0016] The assigning of each task to one of the vessels may comprise minimising the amount of time for said vessel to complete the task.

[0017] Minimising the task completion time helps to quickly free up the vessel for new task and saves time and money. On top of that, minimising the task completion time improves the quality of service offered to the clients serviced by the vessel fleet.

[0018] The amount of energy required for the vessel to complete the task is preferably calculated taking into account not just the energy required for performing the task, but also an amount of energy required for the vessel to travel from the location of the vessel to the location of the task. For a task that needs to be performed immediately, this additional amount of energy required is calculated from the vessel' s current location. For a task to be performed later, this additional amount of energy required may be calculated based on an expected or scheduled location of the vessel at the point in time when it may be dispatched to perform the respective task.

[0019] The calculation of the energy required for the vessel to complete the task may further take into account an amount of energy required for the vessel to travel to the at least one battery charger after completing the task. When the state of charge of the vessel batteries is expected to be below a minimum threshold after the completion of a particular task, or if the state of charge is insufficient for enabling the vessel to perform a subsequent task, a charging event may be scheduled after the completion of an assigned task. However, if during travel to the battery charger the state of charge of the vessel batteries drops below the minimum threshold, this may have a negative influence on the lifespan of said batteries. Or even worse, the vessel may run out of power and be unable to reach the battery charger at all without being tugged there by another vessel. This can all be avoided by taking into account the amount of energy required for the vessel to travel to the at least one battery charger.

[0020] In preferred embodiments, the assigning of each task to one of the vessels comprises ensuring that a difference between the current state of charge of the battery of said vessel exceeds the amount of energy required for the vessel to complete the task by a minimum threshold.

[0021] This minimum threshold or safety margin may help to increase the lifespan of the vessel batteries and to ensure that all operations can be performed as planned, without needing any later rescheduling. Other safety margins than a minimum threshold for a state of charge of the vessel batteries may include a minimum amount of time between two subsequently scheduled tasks or charging events for each vessel. Using such a time-based safety margin may, for example, reduce the risk that a vessel is not yet available for performing a task when scheduled, or that one vessel is blocking access to one of the battery chargers when another one is scheduled to be charged. Preferably, the method of dispatching a fleet of electrified vessels further comprises receiving local weather information, and the amount of energy required for the vessel to complete the task is further based on the local weather information. The local weather information used for determining the amount of energy required for the vessel to complete the task may be based on current weather information, which may be obtained from local sensors and / or a remote weather information provider. The weather information preferably comprises a weather forecast too. Similarly, the method of dispatching a fleet of electrified vessels may comprise receiving tidal information, and taking this tidal information into account when determining the amount of energy required for the vessel to complete the task.

[0022] Weather and tidal conditions can have a significant effect on the amount of energy required for the vessel to complete a task or travel to and from the task location. For example, and generally speaking, more energy is required to travel upwind or against the tide and less energy is required to travel downwind or with the tide. Factoring the effect of weather and / or tidal conditions into the calculation of total energy requirement for the vessel will give a more accurate prediction of the energy consumption of the vessels. This allows for an improved allocation of tasks and a higher probability that all tasks can be performed as planned, without a need to make further adjustments later. Furthermore, the higher accuracy of the predictions may allow for using smaller safety margins when scheduling harbour operation tasks and vessel charging events. By shrinking such safety margins, the total number of tasks executed by the fleet can be increased even further.

[0023] Preferably, the method of dispatching a fleet of electrified vessels further comprises dispatching individual instructions to the vessels of the fleet for completion of the charging events on the schedule of battery charging events. Alternatively, vessels just move to the nearest, or nearest available battery charger whenever their state of charge drops below a minimum threshold. This minimum threshold may be fixed at a level that ensures that the battery is sufficiently charged to reach the battery charger without fully depleting its capacity. Alternatively, this minimum threshold may be dynamic and dependent on, e.g. , a distance to the nearest battery charger, or weather and / or tidal conditions.

[0024] In preferred embodiments, the method of dispatching a fleet of electrified vessels further comprises dispatching the schedule of battery charging events to the at least one battery charger, such that the battery charger may be able to prepare for oncoming charging events. For example, the battery charger may select, install, and configure a suitable charger connector that is compatible with the charging inlet of the first vessel that is scheduled to be charged. The battery charger may comprise a robotic arm for connecting the charging cable to the vessel' s charging inlet, which robotic arm is parked in a safe and secure storage position when not use and may be employed and prepared for charging, just before the vessel to be charged arrives. The battery charger may refuse an unscheduled charging request, when knowing that it will interfere with the scheduled charging of one of the vessels of the fleet.

[0025] If the at least one battery charger comprises a plurality of charging connectors, the schedule of battery charging events may further be based on a nominal charging power of each one of the charging connectors. The fleet may comprise a variation of vessel types and sizes with different battery capacity. Some vessels may be configured for charging at a higher charging power and may thus be scheduled to be charged by battery chargers capable of delivering such higher charging power . When not enough high nominal power battery chargers are available , vessels with a larger battery capacity or ves sels that are more urgently needed for performing their next scheduled harbour operation tas k may be sent to the high nominal power battery chargers . Smaller ves sels and ves sels that are not urgently needed for performing new ta sks may be sent to the lower nominal power battery chargers .

[0026] According to another aspect of the invention , a system is provided for dispatching a fleet of electrified ves sels for harbour operations , the system comprising a controller conf igured to perform a method as de scribed above .

[0027] According to a further aspect of the invention , a computer program product is provided comprising machine readable instructions which , when executed by a computer , are arranged to perform such a method .

[0028] Brief Description of the Drawings

[0029] Figure 1 shows a schematic of an example electrified ves sel for harbour operations .

[0030] Figure 2 shows a f low chart for a method of dispatching a fleet of electrified ves sels for harbour operations .

[0031] Detailed Description of the Drawings

[0032] Figure 1 shows a schematic of an example electrified ves sel 200 for harbour operations . Inside the ves sel 200 , a battery pack 202 is provided for powering the propuls ion of the ves sel 200 . This battery pack 202 may be charged by battery chargers provided in or near the harbour where the ves sel is operating . Figure 2 shows a flow chart for a method 100 of dispatching a fleet of electrified vessels 200 for harbour operations . These harbour operations range in scope but primarily relate to guiding and / or towing large vessels 200 which may struggle to navigate the confines of the harbour on their own. The vessels 200 for performing the harbour operations may be referred to as tugboats, or tugs for short. Alternatively, tugs may be used to fight fires or to tow vessels that have no movement capability such as barges, rafts or disabled ships. At a high level, the method 100 comprises an input stage 102, a processing stage 104, and an output stage 106. While these stages 102, 104, 106 may be performed sequentially and repeatedly, the method preferably is a continuous mix of data gathering, data processing, and data output. Changing circumstances, updated task descriptions, and completed tasks and charging events may lead to continuous updates to the lists of tasks assigned to each vessel and the schedule of battery charging events describing which vessel is to be charged where and when.

[0033] The method 100 will be implemented in software and run on a computer system or network of computer systems that may be located in or near the harbour, or somewhere more remote. Communication between the fleet management system and the vessels 200 and battery chargers involved may run through a public wireless telecommunication network, or through a dedicated private communication network.

[0034] In Figure 2, the input stage 102 is represented by a series of inputs 108-118 and a series of monitoring tasks 120-124. The data received at the input stage 102 of the fleet dispatchment algorithm 100 comprises a schedule of tasks 118 relating to harbour operations. Each task on the schedule is defined by at least a task location 108 and a task description 110. The task location 108 indicates where a vessel needs to show up when assigned to perform said task. The task description 110 comprises information about what the vessel 200 is supposed to do. The task description may, for example, comprises a code or short text describing the activity, such as 'tug' or 'accompany' , a desired or required start time and / or end time, a route to follow or target location to reach, a weight and / or size of a ship asking for assistance, etc. For tasks requiring more than one vessel 200, a single task description 110 may comprise a number of vessels that is needed for the task. Alternatively, separate task descriptions 110 may be provided for each individual vessel 200 that needs to be involved in the task. The input data further comprises a current location 112 for each vessel 200 in the fleet, battery information 114 such as a current state of charge (SoC) for a battery of each vessel 200 in the fleet, and battery charger information 116 relating to an availability and / or capacity of at least one battery charger disposed to supply charge to the vessel batteries.

[0035] While the schedule of tasks 118 may only be provided once or periodically, data 112, 114 describing the vessel fleet and battery charger availability 116 is preferably updated more frequently or continuously. Accordingly, the input stage 102 preferably comprises processes for monitoring vessel locations 120, monitoring vessel batteries 122, and monitoring battery chargers 124. Of course, when the schedule of tasks 118 is altered while the fleet is operating, also updates to the schedule of tasks 118 may be processed in the subsequent processing stage 104. For example, when one or more vessels are urgently needed for putting out a fire, they may need to let go of a task that was previously assigned to them and a recalculation of the planning is needed. Delayed or otherwise altered tasks may be highlighted or otherwise marked as delayed in any visual overview of the task schedule. The length of the delay may be stored and displayed too. Furthermore, once a scheduled and assigned task has been completed, the schedule of tasks 118 may be updated by, e.g. , removing the task from the schedule 118 or marking the task as completed.

[0036] The vessel location monitoring process 120 mainly involves a continuing cycle of receiving vessel location data and updating a database or register with the most recent location data 112 for each vessel. All or part of the historic data may be maintained for commercial or legal reasons and could be used as training data for further improving the optimisation algorithms used in the fleet dispatchment algorithm 100. The vessels in the fleet will typically be equipped with global positioning system (GPS) sensors that can act as a source for the location information 112 of the respective vessel and as input for the vessel location monitoring process 120, but other known ways of tracking vessel locations may be used.

[0037] The battery monitoring process 122 may, e.g. , involve receiving vessel state-of-charge (SoC) data, receiving battery capacity data, and updating a database or register with the most recent battery data 114 for each vessel. The electrified vessels may have an onboard battery management system (BMS) that automatically and / or on request provides the battery data 114 to the battery monitoring algorithm 122. Battery data 114 may, for example, be expressed as a percentage of the total battery capacity, or an amount of kilowatt-hours left in the battery. When it is preferred to not fully deplete the batteries before recharging, the SoC may be indicated relative to a minimum charging level instead of to full depletion.

[0038] The battery charger monitoring process 124 may be used to keep track of various aspects that are relevant for planning the dispatching and the charging of the electrified vessels of the fleet. For each of the at least one battery chargers provided for charging the batteries of the vessels, the current availability status is monitored. This may be done by periodically requesting the battery chargers to communicate their current status, or each charger may submit a status signal each time its availability status changes. For battery chargers configured to charge more than one vehicles at a time, availability may be partial and expressed as a number of available charging connectors, or a portion (percentage, kW, or MW) of the chargers nominal charging power that can be made available for charging vessel batteries. Some battery chargers may be mobile and change location. In that event, the battery charger monitoring process 124 may further comprise monitoring the battery charger location.

[0039] In addition to the current availability status, the battery charger monitoring process 124 may monitor the future availability of the battery chargers . Future availability will depend on the charging events planned for the vessels in the fleet, but may also be influenced by maintenance schedules or planned use by other vehicles. For example, trucks, buses, and consumer vehicles may show up, announced or unannounced, at the battery charger for charging their batteries. Hence, even when there are no changes to schedule of tasks 118 or to the tasks assigned to the vessels in the fleet, it may be important to continue monitoring current and future battery charger availability, such that the task assignment can be adapted to the changing circumstances .

[0040] It should be noted that the abovementioned monitoring steps 120, 122, 124 are independent of one another and the algorithms used for performing these steps may receive, process, and deliver information concurrently, continuously and in no particular order. The input stage 102 is followed by the processing stage 104, wherein the received schedule of tasks 118 and the additional input data described above are processed to efficiently plan the tasks and charging events for the vessels in the fleet. To allow for a efficient planning of all vessel tasks and planning events, it is important that the amount of time and energy required for each vessel to complete the tasks from the schedule of tasks 118. The required time and energy is calculated in a work assessment step 126. For this step, at least the task description 110 of each task in the schedule of tasks 118 will be needed. For a more accurate calculation of the required time and energy for each vessel to perform a task, more information will be needed. For example, the type of vessel, its current location or the location where it is expected to be when the scheduled task needs to be performed, and current or expected weather and tidal conditions may play a role in determining how much time and energy a vessel will need to perform the task. In some embodiments, the work assessment step 126 may include determining a number of vessels 200 required to perform the task. This number may depend on the type and abilities of the vessels 200 that are, or may be made, available for the task 118. For example, it may be determined that a specific task can be performed by either two large or three small vessels.

[0041] In a subsequent processing step, a task assignment algorithm 128 and a charge event planning algorithm 130 determine which tasks are assigned to which vessels, and when and / or where the vessels are going to be charged. The task assignment algorithm 128 and the event planning algorithm may run sequentially, with the task assignment algorithm running first and inserting suitable large gaps in the activity schedule for each vessel to allow sufficient time for charging when the vessel batteries are expected to be at low capacity. Preferably, the two algorithms run in parallel and exchange intermediate results in such a way that an optimal activity and charging schedule can be determined that maximises the number of tasks that can be performed by the fleet in a set period of time (e.g. per hour or per day) .

[0042] It is to be noted that the maximising of the number of tasks always takes place in the context of a set of constraints. For example, legal constraints, safety constraints and cost constraints may be of influence of the total number of tasks the fleet can perform in a set period of time. The task assignment algorithm 128 may thus take into account one or more of such constraints. Additional input data may be used to enable the task assignment algorithm to do this. For example, energy pricing data, or energy pricing forecasts may be taken into account such that all tasks are scheduled and performed in an economically efficient way.

[0043] When the circumstances change or the schedule of tasks is adapted, a recalculation or adjustment of the activity and charging schedule may be desired. In preferred embodiments, the processing stage runs repeatedly or continuously to ensure an optimal deployment of the full fleet. For example, vessel locations 112, vessel battery data 114, or battery charger availability 116, may differ from what was originally planned or expected and the activity and charging schedule may be updated accordingly to ensure that the fleet is used as efficiently as possible. If the battery charger monitoring process 124 keeps track of the planned or expected future battery charger availability, any adaptations to the charging schedule are preferably communicated to the battery charger monitoring algorithm 124 too. In the output stage 106, individual instructions are sent out to the vessels in a vessel instructing step 132, instructing them to perform specific tasks at specified points in time. Preferably, the vessels further receive instructions prescribing when to charge their batteries and to which charger they need to go for having their batteries charged. Additionally, in a charge information dispatch step 134, information about the scheduled charging events may be sent to the battery chargers too, such that they can prepare for the arrival of specific vessels that are coming over to have their batteries charged.

Claims

C L A I M S1. A method of dispatching a fleet of electrified vessels (200) for harbour operations, the method comprising:- receiving a schedule of tasks (118) to be executed by the fleet, the schedule of tasks comprising a location (108) and a task description (110) for each task;- monitoring (122) a current state of charge (114) of a battery of each vessel (200) in the fleet;- monitoring (120) a location (112) of each vessel (200) in the fleet;- monitoring (124) availability of at least one battery charger disposed to supply charge to the batteries of the vessels (200) ;- determining (126) , based on the task description (110) , an amount of time and an amount of energy required for the vessels (200) to complete the tasks in the schedule of tasks ( 118 ) ;- assigning (128) each task to one of the vessels (200) based on the current state of charge (114) of the battery of said vessel (200) and based on the amount of time and the amount of energy required for said vessel (200) to complete the task;- determining (130) a schedule of battery charging events for the vessels (200) and the at least one vessel battery charger based on the current state of charge (114) of the battery of said vessel (200) and the tasks assigned to each vessel (200) , wherein the assigning (128) of each task and the determining (130) the schedule of charging events comprises maximising a total number of tasks executed by the fleet in a predetermined period; and- dispatching (132) individual instructions to the vessels (200) of the fleet for completion of the tasks on the schedule of tasks (118) .

2. The method of Claim 1, wherein the assigning (128) of each task and / or the determining (130) the schedule of charging events comprises minimising vessel travel distance .

3. The method of Claim 1 or 2, wherein the assigning (128) of each task and / or the determining (130) the schedule of charging events comprises minimising vessel idle time.

4. The method of any preceding Claim, wherein the assigning (128) of each task to one of the vessels (200) comprises minimising the amount of time for said vessel (200) to complete the task.

5. The method of any preceding Claim, wherein the amount of energy required for the vessel (200) to complete the task is further based on an amount of energy required for the vessel (200) to travel from the location (112) of the vessel (200) to the location of the task.

6. The method of any preceding Claim, wherein the amount of energy required for the vessel (200) to complete the task is further based on an amount of energy required for the vessel (200) to travel to the at least one battery charger after completing the task.

7. The method of any preceding Claim, wherein the assigning (128) of each task to one of the vessels (200) comprises ensuring that a difference between the current state of charge (114) of the battery of said vessel (200) exceeds the amount of energy required for the vessel (200) to complete the task by a minimum threshold.

8. The method of any preceding Claim, further comprising receiving local weather information, and wherein the amount of energy required for the vessel (200) to completethe task is further based on the local weather information .

9. The method of Claim 8, wherein the local weather information comprises a weather forecast, and wherein the amount of energy required for the vessel (200) to complete the task is further based on the weather forecast.

10. The method of any preceding Claim, further comprising receiving tidal information, and wherein the amount of energy required for the vessel (200) to complete the task is further based on the tidal information.

11. The method of any preceding Claim, further comprising dispatching individual instructions to the vessels (200) of the fleet for completion of the charging events on the schedule of battery charging events .

12. The method of any preceding Claim, further comprising dispatching (134) the schedule of battery charging events to the at least one battery charger.

13. The method of any preceding claim, wherein the at least one battery charger comprises a plurality of charging connectors and wherein the determining (130) the schedule of battery charging events is further based on a nominal charging power of each one of the charger connectors .

14. A system for dispatching a fleet of electrified vessels (200) for harbour operations, the system comprising a controller configured to perform a method according to any of the preceding Claims .

15. A computer program product comprising machine readable instructions which, when executed by a computer, are arranged to perform a method according to any of Claims 1

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