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Wind turbines are tall structures with large blades can produce low-cost, renewable energy, but they also can be deadly to birds and bats. The turbines’ blades turn quickly in the air. Birds and bats fly into them and are killed. But, a new kind of wind generator could solve that problem. In 2002, Spanish inventor David Yanez saw a short film about the Tacoma Narrows Bridge in the U.S. Strong winds caused the bridge to collapse in 1940. It gave Mr. Yanez the idea for a new kind of wind-energy generator. He said it should be as low-cost as possible and need as little care as possible. He also said he wanted it to set up quickly. Mr. Yanez and his friend Raoul Martin took the idea to an engineering business. But they were told their idea would never work. So, Mr. Yanez and Mr. Martin built a small wind tunnel to experiment on their own. They built a large working model of the generator in a field near their workspace. They called the equipment Vortex. Mr. Yanez said there is a mast that serves like a blade on turbines. It is made from the same material as other generators. Wind causes the mast to move back and forth. It does not spin around. The Vortex generator creates less energy than a wind turbine with blades. But it is lighter and less costly to build and maintain. It is made mostly of plastic and has very few moving parts. The current model works at wind speeds ranging from 1.5 to 7 meters per second. Mr. Yanez expects the Vortex bladeless generator to be ready for sale by 2017.