Do Fish Swim Around or Through Energy Devices in the Water?
Understanding Collision Risk Associated with Marine Renewable Energy Devices
with Garrett Staines
Marine renewable energy (MRE) is a vastly progressing industry that harnesses the energy of waves, tides, and river currents using dynamic technologies, like tidal turbines and wave energy converters. Tidal turbine blades rotate with the rising and falling of the tides, creating a locally derived and reliable energy source. The turning blades may create obstacles for wildlife, such as fish, diving seabirds, and marine mammals. Understanding how animals behave around underwater devices is an ongoing goal for Pacific Northwest National Laboratory researchers who need to assess potential effects of these technologies, including the risk of collision.
The Triton Initiative is a U.S. Department of Energy Water Power Technologies Office project that is dedicated to understanding the potential impacts of MRE devices on the environment to remove deployment barriers and make this powerful renewable resource possible. The Triton Field Trials (TFiT) tests methods and technology to produce a set of recommendations for monitoring the environment and progress our understanding of MRE systems’ impact on the environment. TFiT studies four environmental stressors, including changes in habitat, electromagnetic fields, underwater noise, and collision risk.
Fish biologist Garrett Staines leads TFiT’s research on collision risk for animals around turbines. After he received a master’s degree in fisheries from West Virginia University with a concentration in active acoustics for estimating fish abundance, he spent two years as a Peace Corps Volunteer in Fiji, where he was able to apply some of his expertise in fish biology. His path then led him to the University of Maine School of Marine Sciences, where he dove back into the world of acoustics and was introduced to MRE-related research. This research used active acoustic technology to estimate fish abundance and qualify behavior near a tidal turbine in Cobscook Bay, Maine. Staines then journeyed west to begin his career as a research scientist for the Triton Initiative at the Pacific Northwest National Laboratory Marine and Coastal Research Laboratory (MCRL) in 2016.
From the beginning, Staines has played a significant role in developing Triton's vision and has built key partnerships with universities, regulators, and developers. In addition to his work as a task lead for the TFiT collision risk stressor research, he supports U.S. Department of Energy-funded awardees by helping test and develop environmental monitoring technologies and handling environmental permitting. He also leads the development of innovative technology that decreases the resources required to process large datasets associated with underwater video cameras and other sensors. From Staines’s perspective, “any task that brings the marine renewable energy industry closer to a commercial reality is impactful.”
Discovering the Where, When, and How of Animal Collisions
Collison risk is the risk of animals interacting with moving parts, such as rotating blades of current energy converters (CEC) like tidal turbines. This risk could be from animals being attracted to a CEC and getting too close, or water currents overpowering an animal and causing them to be swept into a device. Outcomes could be a near-miss event, a strike leading to minimal or no injury, or a higher consequence strike leading to significant injury and possible mortality. For endangered or threatened species, a single strike and loss of an animal could impact their population—a great concern for regulators permitting the deployment of these devices. In order to understand the extent of this risk, scientists need to know when these interactions happen, and the outcome of collisions.
The recently published OES-Environmental State of the Science report on MRE found no observations of a marine mammal or seabird colliding with a turbine, and only a limited number of fish interactions with turbines, which have not resulted in obvious harm to the fish. Therefore, collisions are expected to be rare, difficult to observe events. The fast-moving, often murky waters make the technology Staines is developing essential to understanding how fish interact and behave around CECs. The industry needs empirical field data collected at operational CEC installations to increase confidence—and that’s exactly what Staines is working toward.
To study this stressor, researchers first need preliminary information about animal presence in specific areas. Regulators require enough of a species present in an area for it to be deemed “of concern” for collision risk. Once identified, researchers determine where and when those species are located in an area. This information is key to providing spatial (where in the water column) and temporal (when during the year interactions may occur) overlap of the animal and the CEC. If an animal is present at the site in the same location and times when the device is operational, there is collision risk potential, and the hard work begins.
Creating Underwater Eyes and Ears
Once a site is identified as having potential collision risk, animal behavior observations are made. Typically, two sensors are used observe animal interactions with CECs at varying ranges, including video cameras and acoustic cameras, also known as imaging sonars. Video cameras can be finicky because they require light and high enough visibility to provide meaningful imagery to document animal behavior and interactions. When low light or murky waters prevent the use of video cameras, acoustic cameras are used to send out acoustic signals to “paint” a picture of the sound in a given location. A third sensor, called a multibeam echosounder, can observe at further ranges than an acoustic camera but with lower resolution. These various technologies can be deployed to observe how fish, marine mammals, and diving birds behave around CECs.
One of Staines’s first Triton Initiative tasks was observing tens of hours of underwater video camera footage for interactions between Pacific salmon smolts and adults and a turbine. This gave him a direct perspective on how fish might interact with an operational turbine. He observed avoidance maneuvers several meters upstream of the turbine to prevent collision and last-second evasion behaviors to quickly avoid the path of a moving blade. Staines’s countless hours were leveraged by software engineers at MCRL to create a data processing software that reduces time and effort analyzing data from underwater video cameras. Now, Staines tests viable methods and instrumentation for studying collision risk to create recommendations for monitoring this stressor.
Observing Fish in Many Habitats Paints a Fuller Picture
In spring 2021, Staines plans to conduct collision risk studies with scientists at the University of Alaska Fairbanks Alaska Center for Energy and Power at the Tanana River test site in Nenana, Alaska, and at the University of New Hampshire Living Bridge. These studies plan to observe the behavior of fish as they swim downstream past deployed river turbines using acoustic cameras. This research will fill data gaps about fish behavior and will inform environmental monitoring recommendations, contributing to Triton’s mission to move the industry closer to installing and testing MRE devices in the water.
Staines also looks forward to conducting research at MCRL, home to the Sequim Bay underwater test bed, which has a tidal channel fit for small-scale CEC deployments. He is designing and testing new technologies and data collection methods to answer questions around collision risk. “By providing important information for regulators and the best technology and methods for monitoring to developers, we can help early stage testing of devices and eventually bring MRE to commercial viability,” says Staines.
While many challenges remain, he is optimistic about the future of MRE and is excited about what’s next for environmental monitoring around MRE devices, such as integrating mitigation technologies with CEC technology. “Developers incorporate several controls in their technologies to improve efficiency and durability. During these phases of development, controls or mechanisms to reduce collision risk can be incorporated,” adds Staines. Conventional hydropower is a good example of how technologies have been incorporated to allow safe fish passage—this will be an important consideration as the industry progresses.
“A personal driver is the long-term, consistent belief that my efforts are supporting the national strategy to integrate MRE into the U.S. energy portfolio,” says Staines. When asked about what excites him most about his work, he had a lot to say. He is excited to work at a research facility that joins forces on a regular basis with other world class organizations to progress the MRE industry, and that he has access to diverse research groups, research vessels, and a scientific dive team that can perform seemingly impossible underwater tasks. Staines’s enthusiasm of his work is felt by all on the Triton team, keeping the team motivated to answer challenging questions and work toward the viability of MRE.
Story written by Cailene Gunn.
The remaining TFiT stressors will be featured over the next few months—stay tuned for more discussions on how the Triton team is researching MRE stressors to help remove the barriers to deploying devices.
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