Electric Ferries Making Headway
January 1, 2018
Hybrid and all-electric ferries are continuing to make headway in Europe where Finland's first all-electric ferry, the 321.5-foot Elektra, has been placed in service on the 15-minute run between Parainen and Nauvo.
Built by Poland's CRIST yard for state-owned operator FinFerries, the new vessel is one of a growing number of electric ferries being built in Europe, and like the world's first all-electric ferry, Norway's 2015-built Ampere, Elektra makes use of Siemens-developed technology. Designed by Finland's Deltamarin the 525-dwt vessel measures 321 feet by 50 feet and has five lanes to accommodate 90 vehicles along with seats for 375 passengers. It is actually a hybrid, with three Scania diesel-generators on board, but these are only brought into use during winter ice conditions. Otherwise the ferry operates on electricity alone, provided by a 1MWh battery bank that receives a quick 5- to 7-minute charge at each end of its 1.6 kilometer route using Cavotec automated mooring and charging stations.
The short charging cycle is sufficient to keep its battery bank charged at its optimum level of about 75 percent. A service speed of 11-knots is provided by two 900kW azimuth propulsion thrusters supplied by Rolls Royce.
In Denmark a true all-electric ferry measuring 195 feet by 39 feet is about to enter service between the Danish mainland and the island of Aeroe after final outfitting at the Scandinavian country's Søby Værft yard. Developed as part of the EU Horizon 2020 initiative, the new "E-Ferry" is a single ended ro/ro passenger ferry with one continuous main deck for 36 vehicles and inside seats for up to 130 passengers.
A principal challenge in the vessel's development has been its relatively long service route of 10.7 nautical miles and the fact that it must complete a full round-trip between battery charges. With this in mind, the ferry has been equipped with a 4.2 MWh Leclanché lithium-ion battery bank that will be charged using a 4MW shore-based charging system to be established in Søby Harbor. The charging system will connect automatically, via plugs, when the ferry arrives and charge each side of the vessel separately at up to 2 x 2MW DC to allow relatively short terminal stays of between 15 and 20 minutes.
A service speed of 14.5-knots will be furnished by two Visedo PowerDRUM 750 kW propulsion motors backed by two Visedo PowerDRUM 250 kW hull thrusters. These motors are extremely light weight for their output, the 750 kW units weighting just under 2,100 pounds each and the 250 kW motors 1,025 pounds each. Once in service the E-Ferry will operate through a two-year demonstration period during which operational data will be collection, with the expectation that its success will place its nine European project partners from Germany, Switzerland, Finland, Denmark and Greece at the forefront of global all-electric marine drive.
In Norway, where a Norwegian funding institution, Innovation Norway, has been partly funding alternative energy projects, a new automatic wireless induction charging system developed by Finland's Wärtsilä has been successfully tested on the hybrid coastal ferry Folgefonn, owned and operated by Norled. The system eliminates the use of a cable connection between the vessel and shore and speeds up vessel turn-around time. It has made the 278ft Folgefonn the first commercial ferry in the world to operate with a high power wireless charging capability for its batteries.
The Wärtsilä system, which is capable of transferring more than a MW of electrical energy, has been designed to maintain efficient power transfer at distances of 19.5 inches between the two charging plates built into the side of the vessel and the pier. To date, no other wireless charging system is as powerful, or capable of maintaining the transfer of energy, at such a distance.