The National Renewable Energy Laboratory (NREL) has deployed buoys to record wave and tide movement off the coasts of Oregon and Maine, in areas known to be potential hot spots for marine and hydrokinetic (MHK) energy development.
Researchers aim to collect data that will support industry’s efforts to deploy MHK devices.
The work is part of larger project funded by the Department of Energy, in concert with Sandia National Laboratories and the Pacific Northwest National Laboratory, to analyze wave and tidal energy sites with great potential for development and gather data to validate the computer modeling tools that industry uses to design devices. New data will fill gaps in existing measurements.
“The data will be publicly available, so device developers can use it in device simulations to test and improve their technology,” said Levi Kilcher, project manager at NREL. “They can also use the data to design arrays of devices.”
NREL recently deployed three subsurface buoys off the Bay of Fundy that will measure underwater tidal water speeds and turbulence, an area of research lacking sufficient data.
One of the buoys is outfitted with sensing technology developed by NREL in another project. Instead of erecting an expensive tower under water—the most accurate way to measure turbulence—the buoy is connected to a mooring system with cables. Sensors record the buoy’s movements, and a sophisticated algorithm separates that motion from turbulence. The buoy will be positioned about 30 feet above the seafloor, imitating the depth of tidal turbines.
It joins two other buoys, known as bottom-landers, which measure tidal flow and turbulence throughout the water column—a vertical slice of water—from the seafloor. Together with the buoy measurements, the bottom landers reportedly provide a more complete picture of the turbulence in the channel and help researchers understand where the most energetic locations of the river are located.
In addition, two measurement buoys deployed off the Oregon coast—where the U.S. wave resource is particularly energetic—will assist in validating computer models for wave energy deployments in shallow waters. To date, most West Coast wave energy measurements have been made in deeper water.
The data will indicate a wave’s height, length, frequency, and direction of travel. The buoys will occasionally be relocated to other promising wave sites.
Previous analysis of wave and tidal energy resources relied primarily on publicly available data or low-fidelity measurements from boats. These studies focusing on regions with high wave energy development potential should reduce risk and cost for developers, who will be freed from conducting their own measurements deemed by the MHK industry as too costly to perform.