Could Sea Floor Carpeting Help Harvest Wave Energy?

Carpet is usually something you try not to get wet. Dirt is a rug’s worst enemy, and when you add moisture of any kind, it becomes a permanent stain faster than you can say “my name is Mud.” According to a study published recently in the Proceedings of the Royal Society, however, installing a special type of carpet on the ocean floor could be key to harvesting the energy of waves on the surface.

In order to understand the rationale behind this underwater carpet, you’ve got to know a little bit about how waves work. Ocean waves form when wind blows across the surface of the ocean. Waves can travel thousands of miles before reaching land, and range in size from small ripples to huge waves over 30 meters high. But it’s when the waves start to approach the shoreline that things get interesting.

ocean-wave-energy-shutterstock

Image via Shutterstock

As a wave gets closer to shore, it begins to drag on the muddy seafloor. This drag slows the wave down and usually shrinks its size (which is good news for those of us swimming near shore!) Watching the mud exert this force on powerful waves gave Mohammad-Reza Alam of the University of California, Berkeley, a brilliant idea: why not create a  rug-like device that could absorb the wave’s energy as it passes overhead?

Alam calls his invention a viscoelastic “carpet of wave-energy conversion” (CWEC), and imagines placing it over a network of vertically oriented springs and generators on the coastal seafloor. “The gravitational force of waves overhead would make the carpet ripple, just as it interacts with mud on the sea floor, and that movement would be transferred to generators,” writes Tina Casey for Cleantechnica.

In early tests, Alam was able to show that the system can easily absorb 50 percent of incident wave energy over short distances of about 10 m. According to Physics World, that’s more than double the maximum possible with wind turbines and at least 20 times greater than currently achieved by solar-power convertors.

Unlike offshore wind turbines or other wave energy harvesting devices, the seabed carpet would be completely impervious to stormy weather. In fact, turbulent seas might actually increase power production.

Beth Buczynski is a freelancer writer and editor currently living in the Rocky Mountain West. Her articles appear on Care2, Ecosalon and Inhabitat, just to name a few. So far, Beth has lived in or near three major U.S. mountain ranges, and is passionate about protecting the important ecosystems they represent. Follow Beth on Twitter as @ecosphericblog

    • Jane Davison

      Wonderful, that is really neat. Having waves and using them for energy then trying to create a kind of carpet device for energy sounds like another form of the renewable energy. Let the storms come and it might just help us keep off or cut down on fossil fuels like Natural Gas and the other things like oil. We just need a little help in thls. Good for Mohmood Alam for coming up with this idea. This is the kind of thing that we need to research and explore. This also has to happen with the waves in lakes as well whether they are little waves or the big ones. Jane Davison

    • http://www.facebook.com/profile.php?id=100002929304682 Jim Page

      another possible form of energy that short sighted people would never consider.  interesting to see what could come of this

    • http://www.londonfloorsanding.org.uk/ Victor Sanders

      This sure looks promising. I think the problem with solar and wind energy is that they are not very efficient, and have periods where they would not be converting much energy. Wave energy or sea floor carpeting has more potential in this sense because the waves are always present. I would definitely like to see more updates about this technology.
      Victor – http://www.londonfloorsanding.org.uk/