Like other renewable energy technology, ocean energy generated by waves, tidal currents or steady offshore winds has been considered full of promise yet perennially years from reaching full-blown commercial development.
That’s still true – commercial-scale deployment is at least five years away. Yet there are fresh signs that ocean power is surging. And if all goes well, WaveConnect, the wave energy pilot project at Humboldt that’s being developed by Pacific Gas and Electric Co. (PG&E), could by next year deploy five commercial-scale wave systems, each putting 1 megawatt of ocean-generated power onto the electric grid.
At less than 1% of the capacity of a big coal-fired power plant, that might seem a pittance. Yet studies show that wave energy could one day produce enough power to supply 17% of California’s electric needs – and make a sizable dent in the state’s greenhouse gas emissions.
Nationwide, ocean power’s potential is far larger. Waves alone could produce 10,000 megawatts of power, about 6.5% of US electricity demand – or as much as produced by conventional hydropower dam generators, estimated the Electric Power Research Institute (EPRI), the research arm of the public utility industry based in Palo Alto, California, in 2007. All together, offshore wind, tidal power, and waves could meet 10% of US electricity needs.
That potential hasn’t gone unnoticed by the Obama administration. After years of jurisdictional bickering, the Federal Energy Regulatory Commission (FERC) and the Department of Interior — MMS last month moved to clarify permitting requirements that have long slowed ocean energy development.
While the Bush administration requested zero for its Department of Energy ocean power R&D budget a few years ago, the agency has reversed course and now plans to quadruple funding to $40 million in the next fiscal year.
If the WaveConnect pilot project succeeds, experts say that the Humboldt site, along with another off Mendocino County to the south, could expand to 80 megawatts. Success there could fling open the door to commercial-scale projects not only along California’s surf-pounding coast but prompt a bicoastal US wave power development surge.
“Even without much support, ocean power has proliferated in the last two to three years, with many more companies trying new and different technology,” says George Hagerman, an ocean energy researcher at the Virginia Tech Advanced Research Institute in Arlington, Va.
Wave and tidal current energy are today at about the same stage as land-based wind power was in the early 1980s, he says, but with “a lot more development just waiting to see that first commercial success.”
More than 50 companies worldwide and 17 US-based companies are now developing ocean power prototypes, an EPRI survey shows. As of last fall, FERC tallied 34 tidal power and nine wave power permits with another 20 tidal current, four wave energy, and three ocean current applications pending.
Some of those permits are held by Christopher Sauer’s company, Ocean Renewable Power of Portland, Maine, which expects to deploy an underwater tidal current generator in a channel near Eastport, Maine, later this year.
After testing a prototype since December 2007, Mr. Sauer is now ready to deploy a far more powerful series of turbines using “foils” – not unlike an airplane propeller – to efficiently convert water current that’s around six knots into as much as 100,000 watts of power. To do that requires a series of “stacked” turbines totaling 52 feet wide by 14 feet high.
“This is definitely not a tinkertoy,” Sauer says.
Tidal energy, as demonstrated by Verdant Power’s efforts in New York City’s East River, could one day provide the US with 3,000 megawatts of power, EPRI says. Yet a limited number of appropriate sites with fast current means that wave and offshore wind energy have the largest potential.
“Wave energy technology is still very much in emerging pre-commercial stage,” says Roger Bedard, ocean technology leader for EPRI. “But what we’re seeing with the PG&E WaveConnect is an important project that could have a significant impact.”
Funding is a problem. As with most renewable power, financing for ocean power has been becalmed by the nation’s financial crisis. Some 17 Wall Street finance companies that had funded renewables, including ocean power, are now down to about seven, says John Miller, director of the Marine Renewable Energy Center at the University of Massachusetts at Dartmouth.
Even so, entrepreneurs like Sauer aren’t close to giving up – and even believe that the funding tide may have turned. Private equity and the state of Maine provided funding at a critical time, he says.
“It’s really been a struggle, particularly since mid-September when Bear Sterns went down,” Sauers says. “We worked without pay for a while, but we made it through.”
Venture capitalists are not involved in ocean energy right now, he admits. Yet he does get his phone calls returned. “They’re not writing checks yet, but they’re talking more,” he says.
When they do start writing checks, it may be to propel devices such as the Pelamis and the PowerBuoy. Makers of those devices, and more than a dozen wave energy companies worldwide, will soon vie to be among five businesses selected to send their machines to the ocean off Humboldt.
One of the major challenges they will face is “survivability” in the face of towering winter waves. By that measure, one of the more successful generators – success defined by time at sea without breaking or sinking – is the Pelamis, a series of red metal cylinders connected by hinges and hydraulic pistons.
Looking a bit like a red bullet train, several of the units were until recently floating on the undulating sea surface off the coast of Portugal. The Pelamis coverts waves to electric power as hydraulic cylinders connecting its floating cylinders expand and contract thereby squeezing fluid through a power unit that extracts energy.
An evaluation of a Pelamis unit installed off the coast of Massachusetts a few years ago found that for $273 million, a wave farm with 206 of the devices could produce energy at a cost of about 13.4 cents a kilowatt hours. Such costs would drop sharply and be competitive with onshore wind energy if the industry settled on a technology and mass-produced it.
“Even with worst-case assumptions, the economics of wave energy compares favorably to wind energy,” the 2004 study conducted for EPRI found.
One US-based contestant for a WaveConnect slot is likely to be the PowerBuoy, a 135-five-foot-long steel cylinder made by Ocean Power Technology (OPT) of Pennington, N.J. Inside the cylinder that is suspended by a float, a pistonlike structure moves up and down with the bobbing of the waves. That drives a generator, sending up to 150 kilowatts of power to a cable on the ocean bottom. A dozen or more buoys tethered to the ocean floor make a power plant.
“Survivability” is a critical concern for all ocean power systems. Constant battering by waves has sunk more than one wave generator. But one of PowerBuoy’s main claims is that its 56-foot-long prototype unit operated continuously for two years before being pulled for inspection.
“The ability to ride out passing huge waves is a very important part of our system,” says Charles Dunleavy, OPT’s chief financial officer. “Right now, the industry is basically just trying to assimilate and deal with many different technologies as well as the cost of putting structures out there in the ocean.”
Beside survivability and economics, though, the critical question of impact on the environment remains.
“We think they’re benign,” EPRI’s Mr. Bedard says. “But we’ve never put large arrays of energy devices in the ocean before. If you make these things big enough, they would have a negative impact.”
Mr. Dunleavy is optimistic that OPT’s technology is “not efficient enough to rob coastlines and their ecosystems of needed waves. A formal evaluation found the company’s PowerBuoy installed near a Navy base in Hawaii as having “no significant impact,” he says.
Gauging the environmental impacts of various systems will be studied closely in the WaveConnect program, along with observations gathered from fishermen, surfers, and coastal-impact groups, says David Eisenhauer, a PG&E spokesman, says.
“There’s definitely good potential for this project,” says Mr. Eisenhauer. “It’s our responsibility to explore any renewable energy we can bring to our customers – but only if it can be done in an economically and environmentally feasible way.”
Offshore wind is getting a boost, too. On April 22, the Obama administration laid out new rules on offshore leases, royalty payments, and easement that are designed to pave the way for investors.
Offshore wind energy is a commercially ready technology, with 10,000 megawatts of wind energy already deployed off European shores. Studies have shown that the US has about 500,000 megawatts of potential offshore energy. Across 10 to 11 East Coast states, offshore wind could supply as much as 20% of the states’ electricity demand without the need for long transmission lines, Hagerman notes.
But development has lagged, thanks to political opposition and regulatory hurdles. So the US remains about five years behind Europe on wave and tidal and farther than that on offshore wind, Bedard says. “They have 10,000 megawatts of offshore wind and we have zero.”
While more costly than land-based wind power, new offshore wind projects have been shown in some studies to have a lower cost of energy than coal projects of the same size and closer to the cost of energy of a new natural-gas fired power plant, Hagerman says.
Offshore wind is the only ocean energy technology ready to be deployed in gigawatt quantities in the next decade, Bedard says. Beyond that, wave and tidal will play important roles.
For offshore wind developers, that means federal efforts to clarify the rules on developing ocean wind energy can’t come soon enough. Burt Hamner plans a hybrid approach to ocean energy – using platforms that produce 10% wave energy and 90% wind energy.
But Mr. Hamner’s dual-power system has run into a bureaucratic tangle – with the Minerals Management Service and FERC both wanting his company to meet widely divergent permit requirements, he says.
“What the public has to understand is that we are faced with a flat-out energy crisis,” Hamner says. “We have to change the regulatory system to develop a structure that’s realistic for what we’re doing.”
To be feasible, costs for offshore wind systems must come down. But even so, a big offshore wind farm with hundreds of turbines might cost $4 billion – while a larger coal-fired power plant is just as much and a nuclear power even more, he contends.
“There is no cheap solution,” Hamner says. “But if we’re successful, the prize could be a big one.”