Sometimes you have to wonder whether wind turbines are built into a building to generate electricity or to add a superficial green sheen. Alex Wilson wrote about it a in 2009 post (covered in TreeHugger in Does Building-integrated Wind Power Work?; since then, there have been a number of projects that just beg the question, like the Chicago parking garage shown above and the Carbuncle Cup winning Strata Tower, where the turbines evidently rarely turn.
First, wind turbines installed on buildings have to be small so that they won’t affect the building’s structure, so the power-generation potential is limited.
Second, wind turbines generate significant noise and vibration. That can be okay when the turbines are a quarter-mile away, but on a building it can be a real problem—particularly with a steel-framed commercial building that transmits noise and vibration throughout the structure.
Third, dealing with turbine installations on buildings increases costs significantly. Special attachments are required, and loads may have to be distributed downward through the building.
Fourth, even if the economics work out it’s hard to believe that insurance companies would embrace the installation of wind turbines on buildings. I suspect that insurers would raise insurance rates significantly, due to the increased liability—or perceived liability—of blades flying off wind turbines or rooftop towers collapsing and damaging roofs. Insurance rates wouldn’t have to rise very far for those costs to exceed the value of the generated electricity.
Finally, it turns out that all that wind swirling by tall buildings is highly turbulent. Wind turbines don’t like turbulence; they do much better with like laminar wind flow. Some types of wind turbines apparently do better with turbulence than others, but most don’t perform well in such conditions.
Then there is the minor point that they don't actually generate much power. Read the whole thing at Building Green.