Wave energy’s potential in the renewable energy industry is undeniable, but progress toward accessible and affordable technology remains a challenge. Technology designed by UMass Dartmouth Civil & Environmental Engineering Associate Professor Daniel MacDonald, in collaboration with engineering consulting firm Boston Engineering, offers new potential in the ability to harness alternative energy from our oceans. The research team received a $239,898 grant through the Commonwealth’s Seaport Economic Council program.
“This is a critical time in the ocean wave energy industry as it offers a still untapped, but significant resource for renewable energy,” Dr. MacDonald said. “Our technological improvements for current wave energy devices are simple, yet may represent a game changer in the wave energy industry. This project will also contribute to the growth of the SouthCoast as a hub for marine renewable energy research and development.”
One type of common wave energy device captures energy from relative motion between two objects. The ocean is an ideal environment for relative motion because waves only move water near the surface, while water deeper than 50 feet below the surface remains relatively motionless. However, this requires that one object be free to float with the ocean surface, while the other extends to the deeper, motionless water.
The penetrating part of the device, often referred to as the spar, can be more than 50 ft. long and is typically constructed of steel. Spars are costly to design and manufacture, and difficult to manage and maintain in the ocean.
To address these shortcomings, the UMass Dartmouth team is designing a flexible, tethered line to replace the rigid spar. The team includes Dr. MacDonald, Roger Race of Boston Engineering, and UMass Dartmouth Civil and Environmental Engineering student Nathaniel Tarantino.
This lighter-weight tether, along with a ballast device at its bottom end, is designed to move down quickly down through the water, but rise up through the water at a much slower rate, while maintaining the line always under tension. This effectively holds the base of the wave energy device fixed, while the buoy portion rises and falls against it, allowing a variety of methods to convert that motion into electricity. The University has filed for a patent for Dr. MacDonald to pursue this wave energy design. Dr. MacDonald and his collaborators hope this will serve as a convenient and low-cost alternative to the conventional method of manufacturing and deploying heavy steel spars into the ocean.
“We are so pleased to continue our collaborative work with UMass Dartmouth and push maritime innovation here on the SouthCoast at the University’s Center for Innovation and Entrepreneurship,” Boston Engineering’s Roger Race said. “The technology could also scale over time to someday complement wind, solar, nuclear, and fossil fuel contributions to the electricity grid.”
The tethered line system could offer immediate impact in capturing energy from waves. Dr. MacDonald and his collaborators are hopeful that the design could have broad use in a variety of marine fields, providing local power sources for autonomous underwater vehicles, navigational systems, ocean monitoring sensors, and telecommunications.