Making Electricity From Ocean Waves
ST. PETERSBURG — Catching a wave never looked like this.
The waves along Florida’s coastline might be used in the future to generate electricity for homes and businesses in coastal states such as Florida and elsewhere.
At least that’s the vision of SRI International, a Silicon Valley-based firm that, for the next month, plans to test a new technology designed to produce power from ocean waves. SRI has offices in St. Petersburg at the University of South Florida’s Knight Oceanographic Research Center.
Generating electricity from the ceaseless motion of the sea is an emerging technology that may have commercial potential in two to 10 years, said Peter Marcotullio, SRI’s director of business development.
SRI’s technology, a cylindrical device encased in a rubber-like material called an "artificial muscle," has been strapped to a buoy and will be launched in the waters of Tampa Bay, about one mile east of downtown St. Petersburg. Researchers plan to measure electricity generation from the device. "This is a test to see how much we can generate," Marcotullio said.
It’s the first of a series of tests that will take place over the next three years, Marcotullio said. The buoy is a prototype — and a far less sophisticated system envisioned by researchers and scientists.
A large commercial system might involve hundreds of larger buoys linked together, floating a few miles offshore and capable of generating 1,000 watts of power, Marcotullio said. The power can be stored in a battery aboard the buoy and transmitted to distribution facilities on land through an underwater power line.
"We imagine a series of buoys or similar structures in the water absorbing the energy from waves and generating electricity to sustain our growing economy," Marcotullio said. "There are designs that look like wings under water."
SRI’s research is being funded by Hyper Drive Corp., a Japanese company that specializes in commercializing technologies capable of producing energy from ocean currents.
"We’re working with them to develop this technology, commercialize it and make it available throughout the world," Marcotullio said.
The key element in the design is a polymer or low-cost rubber.
"It has the complexity of a rubber band," said Roy Kornbluh, senior research engineer for SRI.
The sheet of polymer is tied to a weight, which expands and contracts the polymer as the buoy moves up and down with each wave. Each movement is converted into about 5 watts of electricity, which can be stored in a battery aboard the buoy.
"Think of the artificial muscle as a spring with a weight on it," Marcotullio said. "As the spring expands from the wave, it captures energy from the wave. As it contracts, it releases that energy into either a battery or some other storage."
The waters of Tampa Bay generate currents strong enough for testing, but they are not suitable for a commercial-scale system because the waves in the Bay aren’t big enough.
The Gulf Stream, a swift current which runs just off Florida’s eastern coast, is the best place to locate systems designed to use ocean currents to produce electricity, Marcotullio said.
"If you could capture a significant portion of the energy from the Gulf Stream, you could power the entire United States," Marcotullio said.
Wave power is more expensive than coal-and-gas fired power, but it produces no greenhouse gas emissions and requires no fuel.
It could be a valuable tool in meeting Gov. Charlie Crist’s new mandate to lower greenhouse gas emissions and increase the use of renewable energy sources by Florida’s electric utilities, said St. Petersburg Mayor Rick Baker.
"There can be nothing more ideal than to use the ocean to identify alternative forms of generating electricity," Baker said.
Reporter Russell Ray can be reached at (813) 259-7870 or rray@tampatrib.com. COMING SUNDAY in Business & Money: a look at how utility companies may have to adapt to Gov. Crist’s mandates.