U.S. Department of Energy - Energy Efficiency and Renewable Energy

Water Power Program

Manta Wings: Wave Energy Testing Floats to Puget Sound

August 6, 2010

Columbia Power Technologies plans to test an intermediate-scale version of its wave energy converter device in Puget Sound later this year.

After the successful control tests, the company will move testing to open water in Puget Sound this fall. Columbia will test the intermediate 1:7 scale prototype, which will stand approximately 11 feet tall.  

"Puget Sound has the appropriate scale waves for these test models. It's mimicking a real ocean environment," says Reenst Lesemann, VP of Business Development for the Corvallis, Ore.-based company.

Earlier this year, the company tested a smaller 1:15 scale converter in the wave flume at Oregon State University's O.H. Hinsdale Wave Research Laboratory.

Like Manta Wings

The device, which  is called Manta because its movements are similar to those of a manta stingray, sits like an iceberg on the water. Even at nearly 80 feet tall, only 10 percent of the full-scale devices are visible on the surface.

The wave energy converter device is a permanent magnet generator. As the device floats on the water, the wings of the manta rotate around an axis with the movement of waves. A plate at the bottom of the device provides inertial resistance against the movement of the wings to help create more energy.

Columbia's device takes the energy from the ocean to actuate two permanent magnet rotary generators. These generators create electricity, which is collected from all devices in the wave farm, transmitted ashore to connect into the grid — and then subsequently delivered to homes and businesses.  

"The electricity generated in each wave energy device is collected in a centralized device —a pod— sitting on the sea floor. That aggregated electricity is then fed into a single line to transmit it ashore," Lesemann explains. "At some point, the line will be buried before landfall and will, once inland, be routed above ground to be tied into the grid."

Columbia hopes to have the device fully developed sometime in late 2011 or early 2012. When they're fully developed, the devices will be designed, installed and maintained by Columbia in its customers' offshore wave farms. The size of the farm—which will be two to three miles offshore—will vary, much like wind farms can vary in size.

Lesemann estimates that in an Oregon-like environment, the annual output for each device, as currently designed, would be between 1,500 to 2,000 MWh. The company continues its work to improve the device's output while lowering its construction cost.

Funding the Floating

Columbia received a Small Business Innovation Research grant and an Advanced Water Energy grant from the U.S. Department of Energy to help fund the project.

"The private capital sources willing to take the risk at this point are somewhat limited, so it takes a public/private collaboration to deliver this device to the market," says Lesemann.

So far, the project has already created a number of jobs in Oregon where Columbia Power is based.

"We've used a number of consultants and partners, both on research and development, and also on the environmental, manufacturing and deployment sides," says Lesemann. "These are good family jobs, ranging all the way from R&D to manufacturing. It really runs the gamut."