The Ocean Comes to Colorado

NREL’s First Wave Tank Could Fast-Track Novel Marine Energy Technologies

April 14, 2021 | By Caitlin McDermott-Murphy | Contact media relations

An empty wave tank in a facility
NREL’s new wave tank, pictured here without its rolling waves, could help accelerate the development of commercially viable marine energy technologies to provide clean ocean and river energy to communities across the United States. Photo by Joe DelNero, NREL

Plastic pollution is so pervasive, scientists recently found a plastic grocery bag in perhaps the most unlikely place on Earth—the Marianna Trench, which is the deepest part of the world’s oceans. Other, more benign, man-made inventions (like this ocean broom named Jenny) are helping clean up the mess, but these sea sweepers need a power source—preferably a clean one, like, for example, the ocean itself.

Ocean energy, also known as marine energy, is renewable power generated from the motion of ocean waves, currents, and tides. Soon, marine energy could power Jenny along with seafaring robots used in marine research, buoys that monitor for dangerous tropical storms, booming offshore industries that make up the blue economy, and eventually, in part, the U.S. electrical grid. But no marine energy technology has achieved commercial success—yet.

That is where the National Renewable Energy Laboratory (NREL) comes in. At the laboratory’s Flatirons Campus, NREL researchers help shepherd marine energy prototypes from abstract concept to the market. And the laboratory just installed a new tool that fills a critical gap in that soup-to-nuts support.

“There was still a big piece missing,” said Rebecca Fao, a research engineer in NREL’s water power technology group. “We still couldn’t fully emulate the conditions that these devices will experience when they go offshore.”

Now, they can—well, almost. Thanks to funding from the U.S. Department of Energy’s Water Power Technologies Office, Fao and her team installed their first wave tank in Spring 2022. The tank, coupled with a motion platform scheduled to arrive in March 2023, is “bringing the ocean to Colorado,” Fao said.

Together, the two tools can help accelerate the development of ocean-bound technologies, including marine energy devices as well as offshore wind turbines and floating solar panels, saving developers time, money, and reducing risk as they develop the renewable energy technologies needed to build a 100% clean energy future.

Previously, ocean energy companies like C-Power trekked to Colorado to get NREL’s expert analysis, for example, on how much energy their devices might produce and how well they could handle the ocean’s big, volatile waves. But once they build their prototypes, these teams headed out to find a wave tank or go straight to the ocean, which can be an expensive and risky gamble. “If something goes wrong during your deployment, it’d be very difficult to go out and fix it,” Fao said. “Oftentimes, you can’t fix it.”

Now, with a wave tank available in house, developers can stay put and try out multiple early-stage, small-scale designs, tweaking as they go, or test how seaworthy their instrumentation systems might be. This fast prototyping speeds the development process and saves developers money, too.

True to its name, a wave tank is a shallow chamber used to create waves. NREL’s is about 45 feet long—about the length of three cars parked in a row—8 feet wide, and a little more than 4 feet deep. Though it is nowhere near the size of the largest wave tank in the world, which is used to study tsunamis, it is plenty big enough to test miniaturized wave energy prototypes. The tank produces waves as tall as 8 inches, which move at varying speeds, and because one side is glass, researchers can also watch what is happening beneath the water’s surface. That is important to assess mooring systems, which tether some marine energy devices to the ocean floor.

Alone, the wave tank is a useful early-stage validation tool. But it is just one member of the vast machinery available at Flatirons Campus. Just by walking across the street, NREL researchers and industry partners can try out new ideas—rapidly—to see which technologies have the most promise. On a single campus, a developer can test their design through theoretical modeling before manufacturing and testing a small-scale prototype and even prepare a full-scale device for the open ocean.

In 2023, NREL researchers will install a motion platform, which, also true to its name, is a platform that simulates motion—in this case, the motion of the ocean. The tool, which can support about 22,000 pounds (the weight equivalent of more than five average-sized cars) and can mimic wave movements of up to about 8 feet, will provide a controlled environment in which to test the dynamic behavior of even larger marine energy prototypes as well as scaled offshore wind turbines and floating solar panels. Because the tool can imitate a wider spectrum of ocean movements and serve more technologies, it will be one more big puzzle piece added to NREL’s theory-to-ocean support.

“Our goal,” Fao said, “is to conduct end-to-end testing of these devices before they go out on open waters. Our new wave tank and motion platform will make this validation possible at one location: NREL.”

Want to take advantage of NREL’s end-to-end testing capabilities? See what else you can do, learn more about the wave tank and motion platform, and get the latest on NREL’s facilities when you sign up for the NREL’s water power newsletter.

Tags: Water,Marine Energy