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Why Wave Power Has Lagged Far Behind as Energy Source

Challenges, including the design of a device to capture the energy of waves, have stymied efforts to generate electricity from the sea.
 
 
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It’s not difficult to imagine what wind energy looks like — by this point we have all seen the towering turbines dotting the landscape. The same goes for solar power and the panels that are  spreading across rooftops worldwide. But there is another form of renewable energy, available in huge quantities, that doesn’t really call to mind anything at all: What does wave power technology look like?

Wind and solar power have taken off in the past decade or two, as costs have come down rapidly and threats from climate change have made clear the need to transition away from fossil fuels. Meanwhile, numerous  studies have concluded that wave power — and to a lesser extent, tidal power — could contribute massive amounts to the overall energy picture. But while the industry has made halting progress, experts agree that it remains decades behind other forms of renewables, with large amounts of money and research required for it to even begin to catch up. 

No commercial-scale wave power operations now exist, although a small-scale installation  did operate off the coast of Portugal in 2008 and 2009. In February, U.S. corporate giant Lockheed Martin announced a joint venture to create the world’s biggest wave energy 

power-generatinproject, a  62.5-megawatt installation slated for the coast of Australia that would produce enough power for 10,000 homes. Scotland, surrounded by the rough waters of the Atlantic and the North Sea, has become a hotbed of wave-energy research and development, with the government last year approving a 40-megawatt wave energy installation in the Shetland Islands. 

But a central challenge has proven to be the complexity of harnessing wave power, which has led to a host of designs, including  writhing snake-like attenuatorsbobbing buoys, even devices mounted discreetly on the ocean floor that work by  exploiting differences in pressureas a wave passes by. Some devices generate the electricity on the spot and transmit it via undersea cables to shore, while others pass the mechanical energy of the wave along to land before turning it into electrical energy. Which of these drastically divergent concepts might emerge as a winner is far from clear. 

“We may not have even invented the best device yet,” said  Robert Thresher, a research fellow at the  National Renewable Energy Laboratory

From a technical point of view, operating in the ocean is far more difficult than on land; building offshore wind installations, for example, tends to be significantly more expensive than constructing wind farms onshore. Saltwater is a hostile environment for devices, and the waves themselves offer a challenge for energy harvesting as they not only roll past a device but also bob up and down or converge from all sides in confused seas. This provides enticing opportunities for energy capture, but a challenge for optimum design. 

“I’d like to be optimistic, but I don’t think realistically I can be,” said George Hagerman, a research associate in the Virginia Tech University’s  Advanced Research Institute and a contributor to the  U.S. Department of Energy’s assessment of wave energy’s potential. “You’ve got all those cost issues of working in the ocean that  offshore wind illustrates, and then you’ve got [an energy] conversion technology that really no one seems to have settled on a design that is robust, reliable, and efficient. With wind, you’re harnessing the energy as a function of the speed of the wind. In wave energy, you’ve not only got the height of the wave, but you’ve got the period of the wave, so it becomes a more complicated problem.” 

A recurring theme among wave power experts is that wave energy is where wind energy was three decades ago. At that time, engineers had not settled on the optimal design for wind turbines, but decades of ensuing research have resulted in highly sophisticated turbine designs. With wave power, some research occurred after the Arab oil embargo of the 1970s, but since then government and commercial research and development into wave power has paled compared to wind and solar energy. 

As with any energy source, the fundamental roadblock toward more widespread deployment is cost. So far, the wave energy field is  filled with small companiespicking off small amounts of government funding where they can. It will likely require the participation of some large companies, such as GE or Siemens (both major manufacturers of wind turbines) before wave power really gets rolling, according to numerous experts. Those companies may be waiting for the technology to sort itself out before investing, a common dilemma in any nascent field. 

In spite of the challenges inherent to the medium, the industry is progressing, albeit slowly. There are a few small wave farms and pilot projects in the water, including  Pelamis Wave Power’s first-ever wave farm off the coast of Northern Portugal. That company has  a few megawatt-scale wave farms planned, while others, like  Ocean Power Technologiescontinue to deploy test devices to improve buoy-based technology. 

Australian company  Carnegie Wave plans to  commission a “commercial scale” installation near Perth later this year, using a fully submerged  device that uses wave power to pump water to shore for conversion to electricity. And there are signs that big-company buy-in is starting, as evidenced by 

 
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