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Danes take all-battery power to a new level

Ship & Boat International: September/October 2015

Danish shipbuilder Soeby Vaerft has been entrusted with the construction of an all-battery electric ferry to serve the island of Aeroe, on which the shipyard is located. Efficient operating costs, zero emissions, virtually silent running and minimised wake wash will be key attributes of the design, which will have a 4.2MWh energy storage system ­ the highest capacity of any battery installation specified for a ferry to date.

The vessel will also be beyond current state-of-the-art with regard to charging power, charging time and endurance.

On the grounds of its environmental, technological and societal value, the initiative is receiving a large measure of EU funding under the auspices of the Horizon 2020 research programme, in which it is entitled the E-ferry project. If adjudged to be successful, the technology could be taken forward in Europe-wide applications, in coastal zones, island services and inland waterways. The project will also give form to the Green Ferry Vision concept of the Danish maritime community, and provide a template for further renewal of the substantial Danish coastal ferry fleet.

In essence, the newbuild ferry scheme ranks as a demonstration project to prove the performance of an emissions-free, 100% electric-powered passenger and vehicle ferry on longer routes than hitherto ­ namely, of more than 5nm.

Collaborative project
E-ferry is focused on building an innovative vessel combining energy efficient design, lightweight equipment and materials and a state-of-the-art, electric-only system with automated, high power charging, as a cost-effective alternative to fossil-fuelled ferries. The operational and economic feasibility of the concept will then be validated and demonstrated to the industry and ferry operators through the deployment on the Soeby/Fynshav and Soeby/Faaborg crossings in southern Denmark.

Carbon-fibre reinforced (CFR) composite modules, provided by Faaborg-based Tuco Marine, will be used in the E-ferry’s superstructure. All findings from the approval process for the CFR elements for the design will be made available to the wider European maritime industry through the dissemination of project activities and results.

EU money to the tune of approximately €16 million (US$18.2 million) has been approved for the €21.3 million (US$24 million) E-ferry project. The Municipality of Aeroe is coordinating the endeavour with eight partners, namely Soeby Vaerft, consulting naval architect Jens Kristensen, the Danish Maritime Authority, Tuco Marine, the Danish Institute of Fire and Technology(DBI), Hellenic Institute of Transport, electric drive company Visedo, and battery supplier Leclanché. Among the associates are Force Technology, Danish utility South Electric, Svendborg International Maritime Academy, and Dutch ferry operator TESO.

In Denmark, a large collaborative group from the local and national maritime clusters has come together under the banner of the Green Ferry Vision to design and produce the E-ferry prototype. According to the Green Ferry Vision partners, the zero-emission ferry concept allows for a design in which the machinery space is minimal, and which offers total redundancy, high fire safety, improved speed in confined waters and at restricted depths, low energy consumption and fewer crew, making for cost-efficient operation.

The four-year, EU-sponsored E-ferry undertaking began with the first year’s work on detailed design and gaining the necessary approvals. The second year covers the ship construction period, including tests and sea trials. The final two years, corresponding to the ferry’s first two years in service, will be the operational demonstration stage to prove the feasibility of the concept.

The E-ferry prototype, laid out for both passengers and vehicles and adopting a forward bridge, is to be deployed on the Little Belt crossings from Soeby, on Aeroe, to Fynshav and Faaborg, respectively, starting in June 2017. The design has been developed to ensure year-round schedule-keeping in harsher weather conditions than can be achieved with the present vessel, and to cut transit times by up to 25%.

CO2 reduction
Finnish electric drive train specialist Visedo will supply the Aeroe ferry’s entire electrical system, while the record-breaking 4.2MWh energy storage system will be sourced from the Swiss battery manufacturer Leclanché. Earlier this year, the two companies entered into a strategic cooperation agreement, and are among the partners in the E-ferry project.

Visedo, which has also developed the battery management system for the newbuild, attaches extra significance to the ferry deal because industry giant Siemens had earlier been a candidate for the contract.

The ferry is expected to achieve superior efficiency by virtue of lighter construction materials, optimised hull shape and a complete electrical drive train. It is claimed that the design will save approximately 50% in energy compared to the existing diesel ferry, and reduce CO2 and NOx emissions by 2,000tonnes and 41.5%, respectively, per year.

As well as much reduced noise emissions due to silent electric motors, the design will result in considerably less wake wash, by as much as 60-70%, a feature which allies with the bid to reduce the impact of shipping activity on sensitive areas of the shoreline in the shallow Danish waters. Charging power of up to 4MW will allow for quick turnarounds and increase overall efficiency. Until recently, factors of capacity and range have been a barrier to the uptake of battery technology. Leclanché’s energy storage system will be based on banks of lithium-ion batteries.

The banks of batteries will be positioned in the midbody and aftership underdeck areas, with the two propulsion motors and associated gearboxes located between the two battery groupings. With its twin propellers, twin rudders, two bow thrusters, and underwater lines, the ferry will meet high manoeuvrability criteria.

Eurozone job generator
The lightweight approach to the choice of all materials, machinery and equipment, including the CFR composites in the superstructure, compensate for the mass of the batteries to achieve overall ship weight reduction. The hull will be built in steel, but it will not have to bear conventional machinery, fuel tanks and hydraulics. Construction design for the car deck and ro-ro access has been optimised to meet the standards of a two-compartment ferry.

One of the motivations for EU financial backing is that the concept could give competitive advantage to regional shipbuilders throughout the EU by applying the design concept’s blend of innovative technology with lightweight materials. At the same time, assisting a transition from conventional to electric ferries by enhancing local infrastructure could have a positive impact on the social balance in EU regions where production jobs are scarce and disappearing.

Moreover, the introduction of novel, fully- electric ferry solutions would raise the ‘green’ energy profile to the potential benefit of European tourism and technology offering.

For the island of Aeroe specifically, a fleet of four smaller ferries of zero-emission type carrying a crew of three, possibly down to two crew during off-peak periods with low passenger demand, could make for improved, more economic infrastructural links than using three larger, conventional ferries manned by five crew.

The Danish maritime cluster, in particular, is cognisant of the wider opportunities presented through the growth of the knowledge base regarding electrically powered vessels, and the opportunities this presents for local shipyards and specialised sub-suppliers.

A number of Danish operators are already in the industry’s vanguard of the introduction of hybrid electric solutions, but the E-ferry/Green Ferry Vision focus on a low-weight ferry powered solely by renewable energy stored aboard in batteries signifies a major, further advance. 

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