The Promise and Pitfalls of Wave Power

A new facility on the US Northwest coast will test the potential of the ocean to create sustainable, renewable energy.

The waters off the Pacific Coast are salty, dark, and cold. On the calmest blue-sky days, the water can appear nearly flat, gently sloshing against the sides of boats and buoys. But with passing storms, ocean conditions can quickly change, and waves offshore commonly range from 10 to 30 feet high.

wave energy converter in the ocean

PacWave, a full-scale testing center for wave energy devices off the Oregon coast, will be connected to the electrical grid, allowing marine-derived energy to supply electricity to homes in coastal communities as soon as 2025. Photo of a wave energy converter courtesy of the Department of Energy.

To the average person, this may sound unsettling. To scientists and developers of PacWave, the first wave energy research project permitted in US waters off the West Coast, these dynamic wave conditions are perfect.

“Quantitatively, wave energy might be able to account for 10 percent to 20 percent of our global electricity demand,” explains Burke Hales, the chief scientist for PacWave. “But if you build a wave energy device that’s really good for one type of environment, it may not do so good in another type of condition.” Which is why wave energy testing centers are crucial.

The new PacWave facility is planned to be the first full-scale testing center for wave energy devices off the West Coast that will also be connected to the electrical grid, allowing marine-derived wave energy to supply electricity to homes in coastal communities as soon as 2025. Located seven miles off the Oregon coast, between the towns of Newport and Waldport, the test facility will be able to monitor the efficiency and durability of up to 20 wave energy conversion devices. Miles-long undersea cables will connect the devices to the residential energy grid, providing the link between marine generated electricity and nearby communities.

With only a few facilities developed around the world to test the technology’s efficiency and observe how devices hold up against marine conditions, this testing is critical for future “blue energy” development, as wave energy technology is in its infancy compared to other renewable energy technologies. Most existing test facilities have been built in the last decade along Europe’s coastline. But few coastlines are as harsh as those of the Pacific Northwest, a potential wave energy “hot spot” with rough seas and tall waves.

“PacWave itself is going to be a 20-megawatt system,” Hales says. “That’s enough to power a couple thousand family homes, but there’s a lot more homes than that on the coast and globally.”

This is what makes PacWave so exciting to those developing it: It is the first major step toward exploring how the Pacific Coast can produce renewable energy to meet the planet’s growing electricity needs.

Oceans cover approximately 70 percent of the Earth, creating 372,000 miles of coastline. This provides ample possibilities for renewable energy production. An analysis by UK-based wave technology developer Marine Power Systems found that wave energy could provide 10 percent of the global energy demand by 2050.

There are, of course, down sides.

A variety of floating technologies have been developed to transform mechanical energy in a moving wave into electricity, which is then transported through a cable on the seafloor to shore-based facilities. Both the floating devices on the ocean surface and the underwater cables are typically anchored to the seafloor. This means that wave energy production involves introducing foreign infrastructure into the marine environment. So, while wave energy is an exciting new prospect, care must be taken with ocean’s complex ecosystems, which provide abundant fisheries resources and wildlife habitat.

Potential impact to the marine environment from this infrastructure is far reaching, including effects on marine mammal migration, behavioral changes in electricity-sensitive fish like sharks and salmon, and broader impacts on wave dynamics and beach erosion. While all these concerns are legitimate, results of early testing at research facilities show that if they are taken into consideration during the design process, the likelihood of negative impacts can be minimized or avoided.

Hales acknowledges the risks of adding electrical cables and foundation footings to the sandy offshore environments of the Pacific. “There’s high likelihood that fishing gear, like crab pots, could get caught on wave energy converter moorings,” he explained. “That could increase the risk of whale entanglement, and we’ll have to deal with that.”

Numerous whale species migrate along the Pacific Coast, including endangered North Pacific right whales and federally listed populations of Pacific humpback whales. While Hales points out that cables linking the floating wave energy devices to the seafloor will be taught rather than slack (thereby decreasing the chance of entanglement), fishing equipment can wrap around it, creating entanglement danger for whales.

To mitigate these effects, the agencies involved in designing the test facility collaborated with environmental groups and the U.S. Fish and Wildlife Service to identify the best time of year to construct the project, avoiding migration months and developing a pre-migration strategy of subsurface investigation to find and remove any fishing lines or crab pots that may be caught along the cables.

The noise emitted from constant electricity production of the wave energy devices also has the potential to impact marine life, by changing the “soundscape” of the ocean around them. Fish species detect and respond differently to sounds in their environment, with some species attracted to noise and others repelled.

“If wave energy devices are functioning properly, they shouldn’t make a lot of noise,” says Sarah Henkel, associate director of the Pacific Marine Energy Center and the environmental project leader at PacWave. “One of the goals of this test facility is to see what the normal operational noise is.” However, “if one of the devices breaks, we don’t know what that produced sound would be.”

The addition of hydrophones and other hydroacoustic devices around testing facilities will advance researchers’ understanding of how changes to the marine soundscape from wave energy devices, both normally and irregularly functioning, affect marine species.

The emittance of electromagnetic fields (EMF) from the cables is another factor that scientists have theorized could impact fish behavior. The ocean is a giant liquid conductor that could allow electricity to travel outside its cables, potentially affecting species like rays, sharks, and salmon. However, improving cable technology to shield this electricity loss has led researchers to believe this will not be a major concern.

“The EMF signal around these cables is predicted to be so low that we will be challenged to even detect it,” Hales says. “Even at levels that are measurable, it’s not expected to be environmentally harmful. My suspicion is that we’ll go out there and won’t be able to detect anything.” The emittance of EMF from the cables can be further reduced by burying the cables one to two feet below the seafloor, a step that other wave energy facilities have opted for to reduce impacts on marine life.

Further concern for fish behavior stems from the construction of anchoring foundations on the seafloor, something that researchers agree will lead to fish aggregating where they likely would not have gathered before.

“The infrastructure would essentially be an artificial reef,” Henkel says. Adding infrastructure to what used to be a sandy sea bottom leads to growth of primary producers, attracting smaller fish and their predators. Some countries, like Sweden, have tested potential positive effects of wave energy anchors on fish populations by adding holes and nooks to the foundations, leading to additional artificial habitat and increased abundance of certain crustaceans.

“If we are going to move forward with this technology as a nation, there is a way to make it some sort of enhanced habitat,” Henkel says. “But the industry is just not there yet.”

While many impacts of wave energy on the marine environment have been theorized and are being investigated, many unknowns remain, like just how much energy can be produced, and if that energy will be worth the environmental impacts. There is also a looming question of how a large, full-scale wave energy production system would affect the marine environment, compared to the relatively small test facilities around the world.

Heather Mann is the executive director of the Midwater Trawlers (MWT) Cooperative and commercially fishes for pollock, herring, and groundfish along the West Coast. Mann and the MWT were one of the local organizations consulted when scientists were first planning the energy test site.

“PacWave collaborated with fishing groups and marine mammal groups from the start,” she said. “It took years to find and agree on a site.” Still, she has mixed feelings.

The areas in and around the PacWave testing centers will be off-limits to fishing vessels, which means recreational and commercial fishermen lose valuable fishing grounds. Mann said that she and the MWT were happy for the authentic engagement that the scientists and planners of the wave testing center sought while designing the facilities. The successful collaboration between scientists, environmental groups, and fishermen resulted in identification of sites that would avoid major whale migration routes and areas of high commercial fishing effort.

However, considering the potential expansion of wave energy along the West Coast, Mann said fishermen and coastal communities have a real reason to be concerned.

“I don’t think privatizing and industrializing the ocean is smart,” she said. She explained that people assume commercial fishermen are anti-marine renewable energies because they will lose fishing grounds where the energy facilities are located. But it is more than that.

The huge potential footprints of marine renewable energies, both of wave and offshore wind facilities, means less space for commercial fishing and less money for the community.

“All these dollars we earn by bringing fish in go right back into our coastal communities,” Mann explained. In contrast, money generated from the new renewable energy sites may not stay local. “Who is going to fund the local school baseball team? With what money will local restaurants be supported? A lot of that in coastal towns comes from local fishermen.”

“We are certainly pro-renewable energy,” Mann said. “We just need to be careful to weigh the importance of sustainable fisheries against potential gains of ocean energy.”

While wave energy is young in the world of renewable energies and the construction of this technology may have negative consequences on the marine environment, so will climate change, on a much larger scale. Decarbonization will require an innovative combination of techniques to harness renewable energies and decrease reliance on fossil fuels, while avoiding impacts on other renewable resources, wildlife, and ecosystems.

“There’s probably no single renewable energy that will solve our problem by itself,” Hales said. “But waves are slow, steady, and persistent. Unlike solar, waves don’t set.”

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