What do you get if you take the blades off a wind turbine? A better wind turbine. That sounds like a joke, but that’s actually more or less the model of a new wind turbine prototype. Instead of blades that turn in the breeze, the turbine is just a hollow straw that sticks up 40 feet from the ground and vibrates like a guitar string when the wind thrums by. The Spanish engineers who founded Vortex Bladeless in 2010 said they were inspired by the Tacoma Narrows Bridge disaster (maybe not the best pitch for clean energy to a disaster-wary...