Scientists have known for decades that muddy coastal sediments absorb the power of waves as they roll toward beaches. The result is a free service courtesy of soft ocean bottoms that diminishes the sea’s energy before it reaches the communities living beyond them.
Now an engineering team is working to expand the muddy seafloor’s portfolio of services to include power generation. They are building a “carpet” system meant to be installed underwater on coastlines that would harvest power from waves.
"Mud basically moves up and down under the action of the waves and small-scale motions called turbulence occurs within the mud layer and that converts the wave energy into heat," says Reza Alam, a University of California, Berkeley assistant mechanical engineering professor who is leading the effort. "Our idea was to design a carpet that sits on the seafloor and acts like a mud layer to extract energy from ocean waves and convert it into useful energy."
See a video of the project below.
Sitting on top of a volcano may be just what Nevis, a small sombrero-shaped Caribbean Island, needs to become one of the greenest nations on Earth. Frequented by many celebrities including Oprah Winfrey, Dustin Hoffman, Michael Douglas and Beyoncé, this former British colony is about to tap into the geothermal power that lies beneath its pristine surface.
“Nevis is on the cusp of something truly revolutionary,” says Hon. Mark Brantley, Nevis’s deputy premier. “We in Nevis care deeply about the environment—and weaning ourselves off fossil fuels for our energy needs reduces our carbon footprint.”
Generating loads of electricity from moving water might soon shift away from the province of behemoth structures like Washington’s Grand Coulee and China’s Three Gorges dams.
Over the last few years, researchers and industry have been chalking up successes developing small-scale, distributed hydroelectric generators to potentially replace their massive forebears, whose footprint causes major disturbances in the environment and communities nearby. These emerging technologies, collectively called hydrokinetics, can turn moving water in rivers, manmade spillways and ocean tides into electricity that gets pumped into power grids.
“For new projects that need to be started, small hydrokinetic distributed networks should be considered as a viable candidate against big dams or other major power production projects,” says Diana Marculescu, a Carnegie Mellon University computer and electrical engineering professor who works in hydrokinetics. “In the long term, these distributed generation projects can become a serious alternative to large-scale hydroelectric, especially in the developing world, where increase in demand will be much larger.”