Tang, the hybrid catamaran, harbinger of things to come
by Sail-World Cruising on 29 Sep 2010
Tang sailing SW
She's called Tang, and she looks just like a normal catamaran, but normal she's not, she's the harbinger of things to come. US designer and manufacturer of large-format batteries International Battery is joining hands with Electric Marine Propulsion(EMP) to build hybrid power units for big boats and yachts.
The partnership with EMP will aim to build a hybrid power train for the world's largest plug-in, hybrid-electric sailboats -- a 60-foot Tag Yachts catamaran that runs on wind-generated electricity stored in International Battery's lithium-ion batteries.
Christened 'Tang' at its Sept. 21 launch, the carbon-fiber speedster is undergoing tests at Tag facilities in St. Francis Bay, South Africa. It will set sail later in 2010 to its owner in Florida and will appear at the Miami sailboat show in February.
Tang's hybrid system includes twin E motion 18-kilowatt permanent-magnet motors and International Battery's lithium cells configured into a 144-volt battery pack. The pack's total energy capacity is a hefty 46 kilowatt-hours. That's more than twice the usable capacity of an 8D battery pack -- the largest conventional size carried with the E motion system. Yet the lithium pack weighs roughly 40 percent less.
The company said the extra energy capacity would allow the sailing yacht to offer more luxury and power hungry amenities to passengers including a large flat screen television set, entertainment system, lighting, cafe-standard espresso machine, refrigerator-freezers, dishwasher, microwave, conventional oven, gas or electrical burner top, washer-dryer, air-conditioning and a water maker.
Analysts said the latest project could signal major changes in shipping and maritime transport, with the promise of reduced risk of pollution from fossil fuels.
'This is a transformational combination of technologies,' said EMP Chief Executive Officer Dave Tether. 'Our E Motion hybrid system converts wind and solar energy into a practical power source for boat motors and auxiliaries. And, International Battery's lithium cells provide the lightweight, high-capacity storage that really lets us take advantage of it.'
The main renewable energy input to the large-format battery pack is electricity regenerated by wind power as the boat's propellers spin in the wake, under sail. The propellers turn the 18-kilowatt propulsion motors, which automatically become generators and send electricity back to the batteries.
'The initial thrust and response when engaging forward is vastly better than anything experienced with standard diesel propulsion,' said Tim van der Steene, managing director of Tag Yachts. 'It's quiet and the power is there instantly. It goes hand-in-hand with sailing, which is about moving in harmony with nature, quietly, without polluting the environment.'
When there's not enough wind, twin 22-kilowatt diesel generators kick in automatically for recharging, together or individually as needed. The generators are 144-volt direct-current units that recharge the batteries directly without the normal energy loss incurred through a charger.
The batteries also can be charged with a 144-volt charger that plugs into shore power. The charger handles a wide range of voltages and frequencies, a big advantage in out-of-the way ports with erratic supplies of electricity.
International Battery CEO Ake Almgren said the large-format lithium prismatic cells could be used as the building blocks for battery systems with high energy density -- 'which means smaller footprints and lower weight.'
'Because we use a unique, environmentally friendly, water-based manufacturing process, our batteries will feel right at home storing clean, renewable energy for this hybrid vessel and others to follow,' said Almgren.
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