No one knows the most efficient way to capture energy from the constant motion of the ocean. But a recent U.S. Department of Energy (DoE) competition has surfaced some likely options.
The DOE Office of Energy Efficiency and Renewable Energy announced AquaHarmonics as the winner of its Wave Energy Prize. An 18-month design-build-test competition, the Wave Energy Prize attempts to jump-start development of technology for generating cost-efficient wave energy. A collaboration between Oregon State University graduates Alex Hagmuller and Max Ginsburg, AquaHarmonics received the $1.5 million first prize. CalWave Power Technologies and Waveswing America were awarded second and third place, respectively, winnning $500,000 and $250,000.
The AquaHarmonics system is called point absorber with latching/de-clutching control. The system is contained within a cylindrical buoy connected to a mooring line. As the absorber rises on a wave, the line reels out and generates power. The line reels back in when the wave recedes. At full scale, the system would measure about 50 feet in diameter at full scale. Electronic controls maximize capture of wave energy, making it possible to deploy the system across across a range of ocean conditions.
With more than 50 percent of the U.S. population living within 50 miles of coastlines, there is vast potential to provide clean, renewable electricity to communities and cities across the United States using wave energy. – U.S. DoE
The AquaHarmonics point absorber is just one of the many techniques advanced by the competition. Second-place winner CalWave Power Technologies entered a submerged pressure differential device–an underwater mechanism of springy fiberglass “carpets” that flex to capture wave motion. Waveswing America developed a sub-sea pressure-differential point absorber device that incorporated a linear power generator technology and advanced control algorithms to maximize yield.
Ninety-two teams registered for the prize beginning in April 2015, and nine finalists and two alternates, which were announced in March 2016. These teams received up to $125,000 in seed funding to build scaled prototypes of their wave energy converter devices. The finalist teams tested their prototype devices in the wave-making facility at the Naval Surface Warfare Center’s Maneuvering and Seakeeping Basin at Carderock, Maryland. The teams aimed to reach goals set out by the competition to double the energy capture of wave energy per unit structure cost. Four teams achieved the goals, with Aquaponics having the highest scores.
Some of the details in the article first appeared in the Portland Business Journal.