Atmospher Sci & Global Chg
Research Highlights

September 2014

Off-shore Power Potential Floating in the Wind

Buoys loaded with advanced weather instruments will predict offshore power potential

PNNL staff conduct tests in Sequim Bay, Washington, while aboard one of two new research buoys being commissioned to more accurately predict offshore wind’s power-producing potential. Enlarge Image.

Results: Two bright yellow buoys - each worth $1.3 million - are being deployed by Pacific Northwest National Laboratory in Washington State's Sequim Bay. The massive, 20,000-pound buoys are decked out with the latest in meteorological and oceanographic equipment to enable more accurate predictions of the power-producing potential of winds that blow off U.S. shores. Starting in November, they will be commissioned for up to a year at two offshore wind demonstration projects: one near Coos Bay, Oregon, and another near Virginia Beach, Virginia.

"We know offshore winds are powerful, but these buoys will allow us to better understand exactly how strong they really are at the heights of wind turbines," said PNNL atmospheric scientist Dr. William J. Shaw. "Data provided by the buoys will give us a much clearer picture of how much power can be generated at specific sites along the American coastline - and enable us to generate that clean, renewable power sooner."

Why It Matters: Offshore wind is a new frontier for U.S. renewable energy developers. There's tremendous power-producing potential, but limited information is available about ocean-based wind resources. A recent report estimated the U.S. could power nearly 17 million homes by generating more than 54 gigawatts of offshore wind energy, but more information is needed.

Methods: Instruments have long been sent out to sea to measure winds on the ocean's surface, but the blade tips of offshore wind turbines can reach up to 600 feet above the surface, where winds can behave very differently. The buoys carry a bevy of advanced instruments, including devices called lidar, which is short for light detection and ranging, to measure wind speed and direction at multiple heights above the ocean. Other onboard instruments will record air and sea surface temperature, barometric pressure, relative humidity, wave height and period, and water conductivity. Subsurface ocean currents will also be measured with acoustic Doppler sensors.

These measurements will help scientists and developers better understand air-sea interactions and their impact on how much wind energy a turbine could capture at particular offshore sites. The data will also help validate the wind predictions derived from computer models, which have thus far relied on extremely limited real-world information.

Acknowledgments

PNNL is operating and managing the buoys for the U.S. Department of Energy. Researchers working from PNNL's Marine Sciences Laboratory in Sequim, Washington, will conduct initial tests on the custom-made buoys in Seattle area waters. DOE's Office of Energy Efficiency & Renewable Energy purchased the buoys to improve offshore turbine performance in the near term and reduce barriers to private investment in large-scale offshore wind energy development in the long term. The buoys were manufactured by AXYS Technologies, Inc., in Sidney, British Columbia.

For more information, see PNNL news release "Ahoy, offshore wind: Advanced buoys bring vital data to untapped energy resource."

Related stories: PNNL to Map the Wind as Part of DOE Offshore Wind Demonstration Project