By Alexandra Freibott and Shirah Theitje
Harnessing the power of waves, tides, and currents could unlock the secrets to achieving greater energy security with minimal environmental impact. By some estimates, there are enough marine energy resources in the U.S. to meet a whopping 57 percent of the nation’s energy needs—supporting a clean energy future and creating new jobs. But how do we harness that power in an environmentally responsible way?
Reaping the full benefits of marine energy starts with understanding how the devices used to capture the power of the ocean affect sea creatures and the habitats they call home. Research from Pacific Northwest National Laboratory’s (PNNL) Triton Initiative is advancing how the marine energy industry conducts environmental monitoring of marine energy devices. Through the Triton Field Trials, researchers evaluated monitoring technologies and methods to address the lack of industry standards for environmental monitoring of common environmental concerns and provide recommendations that can be used by the marine energy industry to chart a path toward low-impact solutions.
The Journal of Marine Science and Engineering recently dedicated an entire special issue to showcasing the latest research from the Triton Initiative. PNNL benthic ecologist Lenaig Hemery and earth scientist Joseph Haxel organized the ten publications in the issue to address multiple areas of interest in environmental monitoring of marine energy devices, including underwater noise, electromagnetic fields, collision risk, habitat change, and others.
“Together, these articles tell a comprehensive story about the future of marine energy,” Hemery explained, “Each of them focuses on a slightly different research question, but since they are being published in unison, they weave together a bigger picture.”
Cutting through the noise
Of the possible environmental impacts that can result from the introduction of marine energy devices in coastal areas, sound is a major consideration. Many marine animals use sound to understand and navigate their underwater world. Marine energy devices may add to that soundscape, but is it enough noise to impact marine life in the area? Answering this question is key to developing and implementing low-impact marine energy technologies in the right locations.
In one publication in the special issue, PNNL researchers and collaborators at the University of New Hampshire and University of Washington used a hydrophone to measure the noise generated by a tidal turbine in Portsmouth, New Hampshire. They found that turbine-related noise in this bustling port was less than ambient port sounds and concluded that this turbine’s noise was not likely to disturb the local wildlife.
This finding alone is positive news from an ocean stewardship perspective, but their work also demonstrated the efficacy of using an off-the-shelf hydrophone to monitor noise from marine energy devices.
“Proving the effectiveness of readily available, low-cost monitoring options like this hydrophone, coupled with the existing international guidance on acoustic characterization of marine energy converters, opens the door for more opportunities to gather critical, transferable data on acoustic emissions from marine energy devices in the United States,” said Haxel, lead author on this study.
Lights, camera, action on marine energy
The lack of industry standards for the collection of environmental data around marine energy installations has made it difficult to generalize the environmental effects from one device installation to another. Addressing this issue, a unifying theme of the special issue is the importance of transferable and consistent environmental monitoring methods that will support the development and installation of low-impact marine energy devices. The publications in the special issue share valuable results from field trials conducted by the Triton Initiative, reporting on new monitoring approaches and summarizing broader impacts related to the presence of energy devices in marine environments.
- “Seeing” with sound: Researchers found that acoustic cameras—often used where visual monitoring is impossible due to cloudy water conditions—are best for monitoring for potential collisions between larger marine animals and energy devices.
- The ultimate panoramic picture: Researchers identified the best configuration to successfully use a 360-degree camera to monitor fish aggregation around marine energy installations—an approach that will make monitoring possible in locations where strong waves or currents make other options impractical.
- Measuring invisible electromagnetic fields: Researchers tested instruments used to measure underwater electromagnetic fields—which are emitted by cables that transport energy from marine devices to shore—and monitored ambient electromagnetic fields in Sequim Bay, Washington, to establish an important baseline for future monitoring.
- And more: Other publications in the special issue cover approaches to model the environmental effects of marine energy devices, tools to assess habitat change, communication and outreach strategies, the impact of light from marine energy devices, and life cycle sustainability considerations.
Ripples through the marine energy world
Raising the visibility of the latest marine energy research will have a ripple effect in the world of scientific practice and management. The publications in this special issue provide a valuable, multifaceted look at environmental monitoring techniques and approaches that will inform the development of future marine energy technologies, policies, and regulations.
“One of the main barriers for deploying marine energy right now is there simply haven’t been enough devices put in the water and tested,” Haxel stated. “Our mission with Triton is to help fill in the knowledge gaps that regulators have so we can arrive at a set of standardized techniques and equipment that promote transferability.”
Ultimately, ensuring the long-term impacts of marine energy devices are understood by regulators, policymakers, and the scientific community moves the needle of progress on our 21st century energy transition.
All articles are now available in the special issue, “Technology and Methods for Environmental Monitoring of Marine Renewable Energy.” The Triton Initiative is supported by the U.S. Department of Energy Water Power Technologies Office.
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