Berkeley team tackles drought with waves


A research team at the University of California believes it has an innovative solution to not one, but two critical problems facing the state. It's a device known as seafloor carpet, designed to deliver both energy and fresh water.

"As the waves travel over the carpet, you can clearly see the carpet follows the wave motion and the motion drives the hydraulic pumps underneath," says co-developer Marcus Lehmann, PhD.

The prototype is a scaled down version of what could ultimately be a reliable, energy system with the potential to provide other benefits as well. Professor Reza Alam, PhD, who leads the team, says the idea is based loosely on the physics of mud on the sea floor which absorbs much of the turbulence created by waves before they crash onto the shoreline.

"So that's one that came to my mind. If mud can do such a great job, if we place a seafloor carpet on the seabed that responds to the action of wave the same way as mud, then it must be able to take out the same amount of energy from the oceanic waves," Alam explains.

The action of the hydraulic pumps connected to the carpet forces seawater water through a single line, which creates a high-pressure flow that can be used to produce electricity on shore. But in addition to driving turbines, the team believes pumps could also be used to provide something just as valuable to drought stricken California: fresh, drinkable water, forced through desalination filters.

"In fact in the current test we have it generates high pressure water that can be used for desalination. And desalination is the first application we're working on at this point," says Alam.

The team is currently setting up partnerships to create a large scale prototype, and hopes to begin ocean testing within two years.

"With this kind of technology we could fill in the gaps," says Lehmann. "In terms of over-all production of electricity, we could switch over to fresh water, and at night when there's no sun, we could produce electricity."

The carpet isn't the first attempt to harness wave power, but the team believes it has several advantages over competing technologies, starting with durability. Because it sits on the ocean floor, researchers believe it will take far less punishment than surface systems and potentially require less maintenance.

Written and produced by Tim Didion

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