CU study a step toward more-efficient wind farms

January 15, 2014 •

Being first in line has its advantages, even for wind turbines, which are propelled by comparatively smooth wind flow that helps them produce near-optimal power at varying wind speeds.

But in the first row’s wake, turbulence increases and air speed drops, cutting turbine power production and even causing excessive wear on turbines. How that turbulence dissipates is not fully understood.

To start filling that gap in understanding, researchers at the University of Colorado Boulder have performed the first direct measurements of dissipation rates of wind turbines in real-world conditions. Wake turbulence might dissipate faster than commonly thought and in ways existing weather models do not reflect, their study suggests.

Julie Lundquist, CU-Boulder assistant professor of atmospheric and oceanic sciences, presented these findings during a scientific session on weather-driven renewable energy at the fall meeting of the American Geophysical Union in San Francisco.

“We care about wakes not just because they’re beautiful, but studying them will help us understand how to produce more power and minimize turbine maintenance costs,” Lundquist said.

Before this study, turbulence dissipation rates had been directly measured only in wind tunnels. Estimates of dissipation rates from scanning lidar have also been carried out at this location in a previous study in which Lundquist’s research group collaborated with CU’s Cooperative Institute for Research in Environmental Sciences and the National Oceanic and Atmospheric Administration’s Earth Systems Research Laboratory.

That study was just published in the Journal of Atmospheric and Oceanic Technology.

“Although wind-tunnel measurements of wind speed can represent what happens in the real atmosphere, scaling wind-tunnel measurements of turbulence is more difficult,” she added. “We need to compare real-world measurements to wind-tunnel measurements to understand how that scaling works for turbulence.”

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