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issue during construction. The research vessel is used to collect water samples and track marine life in Long Island Sound and the actual ?noise? bene t of the silent propul- sion system was not realized until sea trials were conducted and schools of  sh and other marine life surrounded the vessel during its movements in and out of the harbor, with- out machinery noise or wake. Zero Emissions Full Electric Power While current battery technology is not capable of pro- viding enough capacity for an extended trip, many of the commercial vessels being used today have short durations of run time followed by predictable periods of inactivity. A short run ferry is an ideal candidate for full electric propul- sion; many ferries run for 20-30 minutes and are followed by a 10-15 minute of oading/loading phase. Indeed, the 2014 ship of the year, announced at SMM in Hamburg in September is such a vessel. Norled Ampere, built by Fjell- strand of Norway, is powered by a Corvus Energy ESS. Fully battery electric powered, she has no generator on board. The solution is, in a word, elegant in its simplicity. Due to issues in the local grid where the vessel was op- erating, there was not enough power available to ?quick charge? the batteries after each crossing. Upgrading the local utility grid was deemed time consuming, disruptive and very costly. The engineers at Corvus realized that a battery-to-battery transfer of energy would be far more ef-  cient. In this way, the system would be separated in three parts: an ESS on the vessel, and a shore station on each side. The shore stations are used to fast charge the vessel. When the vessel leaves the dock, the battery then slowly recharges from the grid. With the 30 minute crossing, 15 minute unloading and loading, then another 30 minutes return trip, the battery has ample time to recharge at a slower rate, which is easily handled by the existing grid infrastructure. With a shore station on each side, the vessel battery is fully recharged after each crossing and maintains reserve for additional crossings. Should a power failure occur on either side it is possible for Ampere to recharge on one side only and maintain service without disruption. The Ampere replaces an existing steel monohull design, using diesel mechanical drives with the new Zerocat design. As the name implies, the Zerocat is a catamaran, 260 feet long and is built from aluminum. The owners expect to earn a rapid return on investment from the vessel due to the fact that their operating costs for fuel are now zero. The vessel she replaces burned more than 260,000 gallons of fuel per year and, due to its age, was considered a high polluter. The propulsion system now requires no mainte- PROPULSIONCourtesy of Corvus Energy 2.7MWh Corvus lithium battery system aboard Prinsesse Benedikte.December 201426 MNMN Dec14 Layout 18-31.indd 26MN Dec14 Layout 18-31.indd 2611/25/2014 10:22:10 AM11/25/2014 10:22:10 AM