Ways to Improve Wind Farm Productivity

UCSB mechanical engineer develops ways to improve wind farm productivity. (Image: 12019 via Pixabay)

You’ve probably seen them, perhaps on long road trips — wind turbines with enormous, hypnotic rolling blades, harnessing the clean power of wind for conversion into electric energy. What you may not know is that for the explosion in the number of wind turbines in use as we embrace cleaner sources of energy, these wind farms are quite possibly not as productive as they could be.

UC Santa Barbara mechanical engineering professor Paolo Luzzatto-Fegiz, whose specialty lies in fluid mechanics, said:

“We’ve been designing turbines for use by themselves, but we almost never use them by themselves anymore.”

He added that historically, wind turbines were used individually or in small groups, but as the world moves toward greener energy technologies, they are now found in groups of hundreds or thousands. The problem with these large installations is that each machine, which has been designed to extract as much energy as possible from oncoming wind, may not “play well” with the others.

Fog at an offshore windfarm shows the formation of wind shadows between wind turbines. Photo Credit: VATTENFALL)
Fog at an offshore wind farm shows the formation of wind shadows between wind turbines. (Image: via VATTENFALL)

Wind farm turbines not as efficient as trhey could be

Depending on how the turbines are situated relative to each other and to the prevailing wind, those not directly in the path of the wind could be left to extract energy from significantly depleted airflow. Luzzatto-Fegiz, who is the lead author of “An entrainment model for fully-developed wind farms: effects of atmospheric stability and an ideal limit for wind farm performance,” published in the American Physical Society journal Physical Review Fluids, said:

Similar to how structures can attenuate the flow of light from one side to another, wind power also is lessened as it flows from the front of the turbine to its rear. The result is that not all turbines in a wind farm are living up to their potential. Luzzatto-Fegiz added:

However, according to Luzzatto-Fegiz and co-author Colm-cille P. Caulfield, a professor at the University of Cambridge in the UK, there are ways to get around this issue of diminishing wind returns. And, they said, these enhancements could result in orders-of-magnitude improvements in the energy production of wind farms.

The main goal, according to the researchers, is to give all turbines access to high-velocity airflow, from which they can extract a greater amount of energy. Since the wind above the farm is much faster than between the turbines, mixing the airflow in the wake of the turbines with the air above could be the key to getting more bang for your wind turbine buck. Luzzatto-Fegiz said:

Yet another potential solution is a relatively new version of the wind turbine in which the blades rotate on a vertical axis — like eggbeater blades — as opposed to the traditional horizontal axis. Luzzatto-Fegiz added:

The models developed by the researchers could lead to better-performing wind farms, which in some cases may not require as many turbines as previously thought, thereby reducing potential costs. The models also could result in custom solutions that involve the farm sites’ specific terrain and local weather patterns. Luzzatto-Fegiz ended with:

Provided by: Sonia Fernandez, University of California — Santa Barbara [Note: Materials may be edited for content and length.]

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