Skimming across a man-made lake 300 kilometers southwest of Sydney, the twin-hulled Marjorie K looked like an exotic, overgrown waterbug. The resemblance grew as her crew manipulated the 7-meter boat's "wings" -- long, broad, lightweight modules covered with waterproofed solar cells. Each cell generated electricity just as a solar cell in an everyday pocket calculator does; by adjusting the wings' angle to the sun, the crew gathered more energy for their craft's electric motor.

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