Why waves could be the solution to powering our world
About a mile offshore from Kaneohe Bay on the Hawaiian island of Oahu, a yellow, doughnut-shaped contraption bobs up and down with the motion of the ocean. The hulking device, as wide as a school bus is long, looks a bit like a massive buoy or life raft. In fact, it’s a wave energy converter — one example of a new renewable energy technology that transforms ocean waves into electrical power.
The Lifesaver, as the device is known, is full of gears, cables, and sophisticated electronics. But while other renewable energy devices (like wind turbines and solar panels) are relatively mature technologies, wave energy converters represent a nascent technology. If wind energy has a graduate degree, says Luis Vega, manager of the Hawaii National Marine Renewable Energy Center that’s testing the Lifesaver, “wave energy is still in the first grade.”
But Vega and other experts see big things for wave energy. If they’re right, arrays of wave energy converters moored along coastal regions of the U.S. will be providing power to millions of homes in coming decades.
Like solar and wind power, wave power harnesses energy that comes ultimately from the sun. Solar radiation causes air pressure gradients that cause wind, and wind gives its momentum to the ocean surface, producing waves. As Alam puts it, “Wave power is a very dense form of solar power.”
Just how dense? Every square meter of a solar panel receives 0.2 to 0.3 kilowatts of solar energy, Alam says, and every square meter of a wind tower absorbs 2 to 3 kilowatts. Every meter of the California coast receives 30 kilowatts of wave energy.
Wave energy has another advantage over solar and wind. Waves are easy to forecast, Brekken says. And unlike solar, which works only in daylight hours, wave energy can be harnessed 24/7.