why wind turbines have such skinny blades. Wouldn’t more surface area be more effective?
In: Engineering
Wind turbines extract energy from the air by slowing it down. If you have wider blades you slow down the air more. However that slow air still needs to go *somewhere*, and ends up being pushed out to the sides – but that takes work. The more you slow down the air, the more energy from the incoming wind is used to push the slow air out to the sides. This means additional blade surface area beyond current designs doesn’t give much more energy.
Secondly for a given amount of material (cost) a longer blade sweeps a larger area – which goes up with the square of blade length. Energy extracted goes up with swept area, so you get a lot of extra energy for a little bit of extra length. Blade width doesn’t give you much more energy. This means you get more bang for your buck from longer blades. It’s usually better to build more cheaper turbines than a few more expensive ones.
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