Maersk vice president, head of fleet technology Ole Graa Jakobsen reveals the technology behind its battery pilot and how learnings from it could be applied
Maersk’s upcoming battery pilot on board a box ship will allow the operator to weigh up the benefits versus the retrofit cost – and could lead to it implementing the project learnings to other assets including terminals.
A containerised 600-kWh marine battery system will be installed in a trial on board Maersk Cape Town - the installation is planned for Q2 2020 - to improve vessel performance and reliability while reducing CO2 emissions.
The battery system will be used to improve efficiency of the vessel’s onboard electrical systems such as the generators. By maintaining the vessel’s auxiliary generators at a more optimal load, and avoiding running generators when not needed, fuel consumption can be reduced.
Additionally, it will support the generators with up to 1,800 kVA of power during rapid changes in electrical load such as thruster operation, reducing generator maintenance requirements. The battery system is also capable of providing redundant power, which can improve reliability at sea by ensuring a continuous power supply.
Maersk vice president, head of fleet technology Ole Graa Jakobsen tells Container Shipping & Trade “Our vessels require electricity for lights, machines, electronics and reefers. Today this power is supplied by diesel generators. They do not always operate efficiently. The generators are efficient at high load but often operate at lower loads and are less efficient. A battery can help to optimise the generator’s load profile, and better manage the switching of additional generators. This retrofit involving a containerised battery system is intended to test the value of the benefits of the technology, and to build an understanding of how to maximise these.”
Maersk Cape Town is a 4,500-TEU vessel built in 2011 at Hyundai Heavy Industries, South Korea. It is a Conakry-class ship which sails between West Africa and Asia. Explaining why this vessel was picked for the trail, Mr Jakobsen says “The reason behind this choice is that the vessel sails on long voyages where the battery system can prove its value. A key feature of the vessel is its waste heat recovery system, which allows the batteries to charge by capturing heat loss from the main propulsion as electrical energy. It is the best performing vessel of its class, based on various factors including the crew and systems operation.”
He adds “Within our fleet, there are 21 more vessels in this class, which may fall into scope for a wider rollout.”
The pilot will offer fuel and emissions savings. Mr Jakobsen says Maersk can save 2-3% of total fuel use, leading to saving 820 tonnes of CO2 annually.
Explaining further, he says “With this pilot energy storage system on board Maersk Cape Town, we expect to reduce auxiliary engine running hours significantly. This, and a more efficient engine loading, is expected to result in approximately 260 tonnes of fuel savings annually.”
He adds “It would be a similar percentage reduction for a Triple-E vessel, although the battery system would scale proportionately to expected fuel savings.
“This system cannot support the vessel during a full port stay, however, it does provide for easier future adaptation to include a shore power connection which will be looked at for later phases.”
He says that alongside zero carbon emissions, it is important to highlight the noise reduction and elimination of blackouts.
The containerised battery energy storage system was manufactured in Odense, Denmark by the system integrator and turnkey supplier Trident Maritime Systems.
Explaining why Maersk chose Trident Maritime Systems, Mr Jakobsen says it offered a package that included the engineering and manufacture of the whole system from its components, meeting the stringent requirements for the marine environment. “Other vendors we considered offered to supply the batteries, but not to manage the full system integration.”
Trident is a specialised system integrator, and Trident director energy management & marine conversions Magnus Hansson said this was “key” to this project because “there are many players selling batteries, but we do everything from A to Z”.
He explains the whole process is in close co-operation with Maersk Line. “We start with what kind of battery is appropriate and then look at the ship operating pattern and power consumption profile. One very important aspect is safety and considering all class and regulation requirements. We participate in a dedicated hazard identification workshop with the shipowner, class and authorities to make sure we cover all safety issues. Also, understanding the ships operation profile is key to achieving maximum operation efficiency of the installed equipment, what we call “true demand”.
Mr Jakobsen explains that while the completed battery system is designed to be modular and largely independent of the existing vessel infrastructure, there still needs to be full integration with the vessel systems. “This requires power and control cabling, modification to the main electrical switchboard, connection to the fire detection panel and software updates to the vessel’s control and automation systems,” he says.
A 40 ft container has been selected to house the bulk of the equipment. This includes the six battery racks, containing 108 battery modules. Besides these, there are power converters and a transformer which changes the electricity between the alternating current used on the vessel, and the direct current required by the batteries. There is also a logic controller and a circuit breaker to manage the connection and flow of energy between the vessel and the battery system. A ventilation system is deployed to keep all the components within their correct operating temperature ranges. This battery container is located at the aft end of the vessel above the mooring deck. To access the battery container, another container has been tailored and placed next to it.
A chiller unit for this system is in the second container, which is otherwise used to ensure access into the main container while other cargo sits around and above the battery system.
Mr Hansson says “One of the challenges is to fit all the equipment in the battery container. Also, the container compartment itself has to be fire protected, have the correct A60 fire insulation and be class-approved.”
He adds “The containerised solution has been selected as it allows for flexibility in onboard placement without searching for additional space. It allows for a retrofit standardisation for different container vessel classes as well.”
Asked about the challenges to using a battery on a container vessel, Mr Jakobsen says “Many battery vendors are not yet ready to meet the harsher requirements of the maritime environment – whether this is from a technical, manufacturing or only a certification perspective. A first step is to bring more vendors into this space, broadening the market and over time lowering prices as we have been seeing in land-based energy storage. However, to see widespread adoption of the technology, we require an increase in density of energy for the volume and weight.
“This technology maturation will allow the business case to become viable on more vessels where the cost-benefit ratio would have previously been favourable.
Eventually it may open avenues to other use cases such as propelling ships around ports to reduce emissions, or zero-emissions journeys for short-run voyages – but we are far from that today.”
Explaining how the take up of batteries will aid Maersk, Mr Jakobsen says “We will evaluate the success of the pilot system and where the benefits are primarily realised in a real-world environment. We can then consider whether the cost of such a retrofit weighs up against the benefits to be obtained within the Conakry-class, and beyond that into other classes of vessel. However, the business case is likely to make more sense in newbuildings where we can design the vessels to accommodate a battery system from day one.”
And the battery project could also be applied to other Maersk assets. Mr Jakobsen says “we could implement the learnings among all Maersk assets. Terminals, like vessels, require electricity for lights, machinery, electronics and reefers so batteries can play an important role in terminals, even a more important role than on board a vessel. Other groups of vessels operating differently (tugs, salvage) can still gain from understanding how we have utilised this battery system and how we can maximise the benefits.
He sums up “Maersk anticipates that, in the future, energy storage will become a cost-viable solution to reducing the fuel used by electrical loads on board our vessels.”