The International Information Center for Geotechnical Engineers

Wednesday, 10 October 2018 01:00

How to manipulate windmills full power in a large wind farm

Wind turbines shadow effect-Fog visualization Wind turbines shadow effect-Fog visualization.

Wind turbines convert the wind's kinetic energy into electrical energy. As wind farms utilize more and more windmills, their efficiency is significantly reduced.

Until recently, wind turbines were used separately or in small groups but now the need for renewable energy has triggered the development of large-scale wind farms. UC Santa Barbara mechanical engineering professor Paolo Luzzatto-Fegiz, a specialist in fluid mechanics, states that the problem with large wind farms is that not every wind turbine manipulates the same amount of wind energy. Depending on the location of its neighbors and the direction of the wind, a windmill could be left to extract energy from a depleted airflow. "We've been designing turbines for use by themselves, but we almost never use them by themselves anymore, " Professor Luzzatto-Fegiz said.

According to Professor, a turbine extracts efficiently the energy of the wind but it also lessens its power when flowing from the front to its rear. Therefore, the other turbines cannot operate up to their full potential. "These turbines are now very good at extracting power from wind, but they also form these very big wind shadows. So, you can see that it's not a matter of packing more turbines on your piece of land, because at some point you hit these diminishing returns. There's a point where if you keep adding turbines the amount of power you get (per unit) becomes less".

Nevertheless, a study from Professor Luzzatto-Fegiz and co-author Colm-cille P. Caulfield, a professor at the University of Cambridge in the U.K. shows that there are ways to overcome the issue of diminishing airflows. The key is to provide all windmills high-velocity airflows so that they can extract a large amount of energy. One way to do so is to mix the airflow with the wind above the windfarm which is proved to be much faster. Another solution could be the alteration of the wind turbines design. Scientists believe that the blades would rotate more efficiently on a vertical axis as opposed to the current design on an horizontal axis. "These don't perform as well ordinarily by themselves, but it's significant that they essentially can cause much stronger mixing in their wakes and people have shown that if you put them in an arrangement where they spin in opposite directions to each other they can cause very nice mixing," Professor Luzzatto-Fegiz stated.

Researchers models could alter the way windfarms are designed increasing their energy production capability and reducing the number of wind turbines required.

To find out more about wake effects on wind farms click here.


Read 482 times Last modified on Wednesday, 10 October 2018 13:27

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