American research firm SRI International and Japan's Hyper Drive Corporation today are testing the latest generation of their jointly developed buoy-mounted, ocean wave-powered generator off the coast of Santa Cruz, Calif. As the generator bobs up and down, an accordionlike device inside, made of artificial muscle called Electroactive Polymer Artificial Muscle (EPAM), stretches and contracts, creating mechanical energy that is converted into electricity.

SRI is hoping to demonstrate its ability to generate at least 10 Watts of power in waves about 3.3 feet (one meter) in height, a stepping stone to the 100-Watt capacity the researchers hope to be able to generate within a few years. One of their goals is to replace the 25-Watt batteries that navigation buoys use today with a source of renewable energy that can power additional equipment such as cameras and storm warning sensors.

Once the EPAM buoys are each efficient enough to generate significant power, SRI  may try to link dozens of them to create a wave energy farm that might be an option for delivering electricity to landlubbers. "You could put [a wave farm] on a seawall to power a factory," says Roy Kornbluh, SRI's principal research engineer.

Most other technology developed for harvesting wave power—including Finavera Renewables's AquaBuOY and WaveBob Ltd.'s wave-absorbing buoy—absorbs energy from riding the waves as they bob up and down. Kornbluh points out that SRI's core artificial muscle technology could be added to these other wave buoy technologies to improve their ability to generate power.

The most advanced technology for drawing power from waves, however, looks more like a snake than a navigation buoy. Edinburgh-based Pelamis Wave Power, Ltd., (PWP) has since September been working with asset management firm Babcock & Brown, energy provider Energias de Portugal, and Efacec (a Portugese maker of electromechanical devices) on the Agucadoura project, which has three red Pelamis wave energy converts bobbing in the waves three miles (4.8 kilometers) off Portugal's coast. This first phase will cost about $13 million and generate up to 2.25 megawatts. The company hopes to next year begin building another 25 wave-energy converters that could eventually increase the output to 21 megawatts, which is expected to serve the electricity needs of more than 15,000 Portuguese households.

Images courtesy of SRI