Liquid Power

New advances are being made in the wave energy industry, but can it become commercially viable?


 By Joel Hersch


 

As any surfer will tell you, a heavy ocean swell packs some of the most powerful kinetic energy Mother Nature can serve up. For decades, scientists and inventors have been working to utilize that raw energy—creating devices that can survive the ocean’s harsh environment, mechanically harness the power of waves, and convert their constant motion into a reliable, affordable and transferable source of green energy.

Though a complicated resource to wrangle, the consistent, highly concentrated power contained in waves suggests that it has the potential to one day become the lowest-cost source of energy on the planet. The World Energy Council estimates that approximately 2 terawatts (2 million megawatts) could be produced from the oceans via wave power, and realistically contribute as much as 10 percent of the world’s energy consumption.

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This jellyfish-like pump, called the CETO 6, is Carnegie Wave Energy’s answer to wave energy conversion. Photo Courtesy of Carnegie Wave Energy

The industry, however—which is known as “wave energy conversion”—has struggled to find traction in the commercial market, leaving it as one of the most experimental sectors for renewable energies. But with recent technological milestones, some speculate that the industry could be closer to commercialization than ever before. An assortment of technical and economic hurdles has yet to be transcended, but at the current rate of development, wave energy conversion could play a significant role in the ways communities source power in the near future.

Reenst Lesemann, CEO of Columbia Power Technologies in Oregon, is just one of the individuals in the emerging market hoping to push wave power into the mainstream economy. Citing data from the Department of Energy (DOE), Lesemann explains that wave energy could supply in the ballpark of 15 percent of our projected electricity needs by 2050.

“Just as anyone can check the surf forecast, we can reliably predict the amount of energy coming ashore [with waves],” he says. “This ability to know what is coming, and when, is a really important attribute.”

Everything beyond that, however, is not so simple.

“For a while now, entrepreneurs have been trying to develop safe and efficient wave-power technologies that are environmentally friendly, but the ocean is obviously a difficult place to operate,” Lesemann goes on. “The systems are expensive. That said, significant progress is being made, and we’ll see the first installations coming online in the next few years. Once the market starts in areas with a high local cost of energy or a strong desire to move to renewables, costs will fall rapidly. This will fuel more and more installations, and then you’ll see wave energy enter more mainstream markets.”

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Columbia Power Technologies’ StingRAY energy conversion device. Photo courtesy of Columbia Power Technologies

Because the wave energy conversion industry has been relatively scattered over the years and up until recently lacked centralized, high-dollar investor opportunities, the technology itself has remained highly variable; the field is home to a broad swath of mechanical contraptions, each unique in their own right, yet all designed to accomplish the same goal.

Below, we take a look at three companies that are pushing the industry forward.

 

Columbia Power Technologies

Based in Oregon, CPT is developing a utility-scale energy conversion device called the StingRAY, which floats on the ocean’s surface. The device is meant to be deployed in about 60-meter depths and paired up in a line with other StingRAYs, which together would comprise a “farm,” similar to a series of wind turbines feeding electricity to an on-shore grid via subsea cables.

While anchored to the sea floor, two heavy pillars are suspended below a main floating unit, which has two extended arm levers that float on passing waves, dipping and rising independently. The levers in the arm-floats power a generator and create electricity.

In 2012, CPT made major industry advances with their designs after testing prototype version of the device—called SeaRAY—in 30-foot wave conditions, determining that the model could withstand the heavy forces.

Lesemann says that the company is currently testing their direct-drive generator using a powerful dynamometer—an instrument used to measure an engine’s output—located at the National Wind Technology Center in Boulder, Colo. The tests will determine their readiness to set up more wave energy conversion trials just offshore at a Marine Corps Base in Oahu, HI. The procured power from the StingRAY units will feed the power grid at the military base.

 

Carnegie Wave Energy

In February of this year, Carnegie Wave Energy, located in Perth on Australia’s western coastline, broke the world record by completing 14,000 cumulative operating hours for wave energy conversion machinery. Their device, called the CETO 6, is bit like a huge steel buoy, 36-feet wide and anchored to the ocean floor, floating about a meter below the surface. The energy conversion system utilizes an internal pump that activates as waves pass by above, causing the float, which looks like a giant jellyfish, to undulate up and down. Each unit’s power is converted internally into renewable, zero-emission energy by generators and then transmitted onshore via cables, where they provide an electrical grid at a nearby Australian naval base with 240 kilowatts—about 5 percent of the facility’s average use. The power procured by the CETO 6 units are also used to power a desalination plant that produces fresh water on the base.

 

The CalWave project

CalWave—a project developed by the Institute for Advanced Technology and Public Policy at Cal Poly State University—is currently developing a novel wave energy conversion device called the “Wave Carpet.” With data calculations on the high levels of energy absorbed by a muddy seafloor due to swell, the Wave Carpet mimics an artificial seabed, and, with piston pumps attached beneath the underwater paneling, absorbs the multi-directional forces generated by the passing waves. The Cal Wave program was also recently awarded a $750,000 grant from the DOE. In an effort to accelerate the development of wave-energy technologies in the United States, the DOE is working with a variety of organizations, including CalWave, to construct a National Wave Energy Testing Facility, potentially off the coast of San Luis Obispo, where technology manufacturers can pilot their devices in a marine setting.


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