Denmark’s shortest ferry route is now a pioneer of battery power Since 1958 the shortest ferry route in Denmark has provided a lifeline to Venø island in northern Jutland. It’s a highly scenic ride which today takes only two minutes over the narrow but deceptively 17-meter-deep sound. The current Venø Ferry has transported passengers at 30 minute intervals 36000 times annually since 2010. For six years it used diesel for electric power generation and propulsion, consuming 90,000 liters of fuel each year. In the drive to cut costs and achieve more sustainable operation, the ferry sought solutions to reduce the fuel consumption for the auxiliary power generators. The process was a collaborative development project with Danfoss Drives, EPTechnologies, Super B, Hvide Sande Shipyard, and contractor Vest-El, where the ferry was assessed, the battery supply and power conversion extensively tested, and finally the ferry equipped with a customized hybrid power generation system. From 19 hours of diesel power…. Extensive testing Before the retrofit, the two diesel auxiliary generators were powering the hotel load, bridge equipment, engine room pumps, fire extinguishing equipment and more. With a capacity of 2 x 86 kW dimensioned for worst case scenarios such as fire on board, the typical load was 12 kW, with fuel consumption rather high at 300g/kWh. To meet the demand, these generators ran for 19 hours daily. … to only 20 minutes Before the retrofit Danfoss Drives thoroughly tested the system by using a test rig to simulate the generator. The actual battery and microgrid were employed in this test. The ship’s load was simulated by a Danfoss drive with a load resistor and electrical motors. Danfoss and EPtechnologies performed the economic calculations predicting the reduction in fuel consumption expected with battery-hybrid operation. Now, the battery bank powers electricity consumption on the ferry for each crossing of the 200-m neck of water from Struer to Venø island. To maximize charging time, the staff connect to shore power supply as soon as the ferry reaches shore. In this way, the batteries recharge whilst the next passengers are boarding. With the bank of 88 kWh batteries installed, the auxiliary generators start up to automatically recharge the batteries only when battery power levels begin to drop. Fuel consumption has dropped to 209 g/kWh and the daily generator running time has dropped to only 20 minutes! Battery +– Shore supply = Filter ∼ Micro grid Gen2 G Ship grid 400 V 50 Hz Gen1 G Simplified schematic diagram of the hybrid power generation system. 2 Danfoss Drives ·DKDD.PC.941.A2.02 Test rig simulation of the Super B battery system and VACON® NXC micro grid converter at Danfoss Drives.
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