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Wave of the Future

Patrick Lynett’s research on wave buoys could make wave energy competitive with other alternative energy sources
By: Erin Rode
January 05, 2015 —

USC Viterbi Professor Patrick Lynett
USC Viterbi Professor Patrick Lynett’s research has largely focused on short-term coastal disasters, from tsunamis to hurricanes to typhoons. But with his newest project, he’s attacking a pressing, long-term problem: the ever-increasing need for energy.

Alongside Professor Merrick Haller from Oregon State University, Lynett, a professor in the Sonny Astani Department of Civil and Environmental Engineering, is optimizing existing wave energy buoys by finding a way to predict wave height.

He and his team believe their prediction system could triple wave buoy energy production. This in turn would reduce the cost of wave energy production, improving its status as a potential source of alternative energy, and allowing it to compete with wind and solar energy.

“Marine renewable energy technology has the potential to be an important component of the renewable energy portfolio for most states with access to the sea,” Haller said.

Despite their potential, wave energy buoys are fairly uncommon, mainly because current models are more expensive, and less promising, than solar and wind power. Because of this, wave energy is only practical in locations with large waves and little sunlight like the Pacific Northwest and the United Kingdom, Lynett said.

However, he believes that his research will increase their practicality, leading to more widespread use.

“As with all technology, if you find a few places to apply it, and it turns out to be a functional and practical concept, then the applications expand, and the equipment become more economical,” Lynett said.

Wave energy buoys are often designed to produce energy through simple electromagnetic induction, which is best described as like a spring and coil. As waves jostle the buoy, a magnet is pushed up and down through coil, which induces a voltage. The larger the wave, the more the magnet moves, and the more energy the buoy can produce.

“If you know exactly what the wave is going to be like,” Lynett said, “You can tune the magnet motion to match the frequency and the amplitude of the wave, which would optimize energy extraction.”

The waves provide mechanical energy, which the coil and magnet system converts to usable electricity.

Under maximized energy conditions, a single wave buoy could produce as much energy as 1,000 solar panels. Lynett estimates that one wave buoy has the potential to power anywhere from 50 to 250 homes.

Lynett and colleagues plan to maximize energy output through radar technology. Equipment vehicles parked along the beach would contain radar systems that would send signals out over the ocean, and gather an image of the “wave field,” or wave height and behavior, around a specific buoy.

However, this image only reveals wave height at the time of the snapshot, not what their height will be by the time they reach the buoy. The snapshot alone doesn’t provide enough information for scientists to adjust the buoy for upcoming waves.

         A wave buoy. Courtesy: Ocean Power Technology
Lynett is currently working to solve this by creating a new numerical model. The model will use the wave field information from the radar system to predict what the wave heights will be just a few minutes into the future.

This may seem like a daunting task, but Lynett considers the project a “fun challenge.”

Optimizing wave buoys in this way would produce more energy per dollar put into the buoy, which in turn would make wave buoys a more attractive source of energy.

“If we can make it work, maybe we’ll start to see these types of radar systems set up everywhere, because compared to the value of the energy that you get out of the wave buoy, the radars are relatively cheap,” Lynett said.

Although there’s currently a relatively small market for wave energy buoys, Lynett feels optimistic that through his team’s research, these buoys could become an attractive source of energy for all coastal areas.

“I like to imagine that in a few decades Southern California has solar everywhere, turbines in our windy areas, and wave energy buoys off the coast,” Lynett said.