A few startups have spent millions developing massive underwater power plants that gather energy from ocean waves. But a Florida teenager has invented a small-scale alternative, designed for the developing world, that costs just $12.
Hannah Herbst, age 15, started thinking about renewable energy after talking with her nine-year-old pen pal in Ethiopia. "I found out that she's living in energy poverty, and she doesn't have access to things that I take for granted every day," Herbst says. "Then I was boating with my family through the Boca Raton Inlet, and our boat was really jerked around by the current. I thought, why not use this power?"
Her prototype, which won her top prize in the 2015 Discovery Education 3M Young Scientist Challenge, uses a 3-D printed propeller connected by a pulley to a hydroelectric generator. As waves move the propeller, the generator turns that motion into usable electricity. As part of the contest, Herbst worked with a scientist from 3M to refine the design into a final prototype.
Unlike large-scale ocean energy projects, the tiny system doesn't generate a lot of electricity. But Herbst says it's enough power to run a small desalination machine, turning ocean water into safe drinking water.
Because the main parts are made from recycled materials, Herbst thinks the machine could easily be made anywhere. "When I'm done developing it, I'm going to open source it," she says. "Everybody in the world can have access to the materials list and the data I got—everything you need to make this device. I really want to help my pen pal. I can't imagine a day without energy in my life."