Generating power from the ceaseless motion of the ocean is an industry that is still in its infancy. Important questions about cost, capacity and its impact on the environment continue to linger.
But it’s an emerging technology that will soon be used on a commercial scale in the U.S., thanks to improvements in efficiency, a commitment to environmental stewardship and a lot of collaboration among stakeholders, regulators and industry.
The potential for harnessing ocean waves, currents and tides to produce electricity is vast.
The technical potential for ocean wave power in the U.S. is 90,000 MW, according to estimates by the Electric Power Research Institute. If the U.S. adopted a national renewable energy standard of 25 percent, more than 13,000 MW of that potential could be realized by 2025, according to a study by Navigant Consulting.
Up to 10,000 MW could be feasibly extracted from the swift currents off the coast of Florida, according to Florida Atlantic University’s Center for Ocean Technology.
Ocean Power Technologies (OPT) is working hard to monetize some of this potential.
By this time next year, a license to operate the first commercial scale wave-power project in the U.S. is expected to be issued to OPT.
In August, the New Jersey-based wave-power company reached a settlement agreement with 11 federal and state agencies, fishermen, and tribal officials to build a 1.5-MW wave-energy park about 2.5 miles off the coast of Reedsport, Oregon. The first of 10 PowerBuoy wave energy converters will be placed in the Pacific Ocean next spring for extensive testing, said OPT Chairman George Taylor.
The agreement is the culmination of 38 months of investigation and negotiations with stakeholders. It calls for an adaptive management program that requires a series of tests designed to measure the project’s effect on ocean resources, recreation, safety and other stakeholder interests.
“If there are problems, we will make adjustments,” Taylor said in an interview. “We were thinking about putting our buoys in 40 meters of depth of water, but this was an area where they traditionally put crab pots. So we’ve gone out to between 50 and 60 meters of depth, which is outside the area they normally put their crab pots.
“These are the kinds of things we’re sensitive to,” he said. “We wanted to be good neighbors. That’s the reason for the settlement agreement.”
The conditions of the agreement will be incorporated into the license issued by the Federal Energy Regulatory Commission (FERC).
Stakeholders also are concerned about the wave park’s effect on migrating gray and humpback whales and other marine life. The adaptive management program means OPT will continue to work with the stakeholders after the project is approved by FERC to resolve any issues that might arise. Under the agreement, OPT may be required to change the way it plans to construct and operate the project to minimize certain impacts.
Each 200-ton buoy will have a capacity of 150 kW. Oregon Iron Works of Portland is building the first PB150 PowerBuoy, which will undergo extensive testing before the remaining nine buoys are built and installed. Commercial generation is expected to begin in 2012 after OPT receives a license from FERC and obtains additional funding, Taylor said.
Wave power “has many advantages over wind and solar,” he said. “It’s much more concentrated than wind and solar. Ultimately, it’s going to be less expensive.”
What’s more, wave power is more predictable than wind and solar, Taylor said.
“You can tell days ahead what the waves are going to be,” he said. “You can predict how much energy you’re going to be producing. You can’t do that with wind or solar.”
OPT’s PowerBuoy system is based on modular, ocean-going buoys that capture and convert predictable wave energy into low-cost electricity.
With each wave, the buoy moves up and down on a long cylinder, or spar, that is anchored with a mooring system.
“It is not fixed to the seabed,” Taylor said. “The mooring system keeps the buoy in location.”
The system can generate power with waves between 5 feet and 23 feet high. The PowerBuoy also has a fiber-optic communications and Supervisory Control and Data Acquisition (SCADA) capabilities.
“The clever part is the control system,” Taylor said. “It senses what is the amplitude and what is the period of the frequency of each wave. The sensors are telling the computer this is a three-meter wave and it has a period of 10 seconds between the next peak.”
The Department of Energy awarded $2 million to OPT in 2008 to help fund fabrication, assembly, and factory testing of the first PowerBuoy system. DOE also recently awarded OPT $1.5 million toward developing the next generation of the PowerBuoy with a capacity of 500 kW.
The Reedsport project “will help pave the way for the U.S. to retain a technological advantage in wave power, an advantage that has been ceded to other countries that produce solar panels and wind turbines,” Taylor said.
For more information about OPT’s wave-power park off the coast of Oregon, be sure to read the October issue of Hydro Review magazine.
Russell Ray is senior associate editor of Hydro Review magazine. Russell has 11 years experience as an energy journalist, covering the oil and gas industry in Oklahoma and the growth of solar and nuclear power in Florida. He served eight years as the energy reporter for the Tulsa World. He held the same position at the Tampa Tribune for two and a half years before joining Hydro Review in 2009.
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