Big rotors generate more electricity, particularly from low winds, but oversize trucks hauling blades the length of an Olympic pool can't reach many wind-energy sites. Blade Dynamics fabricates its 160-foot, carbon-fiber blade in multiple pieces, which can then be transported by standard trucks and assembled at a nearby location. It's a stepping-stone for 295-foot and 328-foot blades now being designed for offshore turbines. (Currently, the world's longest prototype is 274 feet.) The colossal size should enable 10- to 12-megawatt turbines, double the generation capacity of today's biggest models.