Wed Aug 1st, 2007 at 10:06:53 AM EST
First posted at dkos
Poor Jerome had to come into the comments and debate the turbines-are-bad-because-they-kill-birds types (thanks).
Recently, I got into another (pointless) debate about whether wind turbines were "eyesores." Debating aesthetics is hard enough, but relying on clever sentences and hand gestures is impossible.
So I went and found some footage I have on wind turbines here in Minnesota and cut them together into a video I called "The Beauty of Windpower" and posted the thing on Youtube. (running time 5:20)
From the diaries - afew
The windmills in this video are found on a spine that cuts diagonally across southwestern Minnesota called Buffalo Ridge. It is Minnesota's only prime wind site even though there are many near-prime sites in the state.
Compared to much of the nation, windpower in Minnesota is fairly advanced. The key development, by far, was a political compromise. Northern States Power (NSP, now Xcel Energy) needed to expand their on-site storage for spent fuel rods at one of their nukes. Political approval for this expansion was withheld until NSP promised to seriously expand their wind capacity.
The reason this worked so well is that it forced a VERY serious utility to fit a windpower division into their organizational structure. By now, it is just as easy to rise in the company ranks as a wind expert as it once was for a nuclear or combustion engineer.
There are always drawbacks to being an early adapter to any technology. A careful viewer of the above video will notice that compared to the latest wind turbines, the Zonds on Buffalo Ridge now look like toys. You can tell their age by how fast they spin.
The reason why big wind turbines must spin more slowly than a small one is explained by an aerodynamic fact--the tips of the rotor blades must never exceed the speed of sound. If the tip speed does exceed the speed of sound, the blades can be severely damaged, the efficiency drops, and they get very noisy. This rule applies to all propellers so much experience has been gained in the aircraft industries.
Even so, modern wind turbines are now so large, they exist in somewhat uncharted territory. Serious engineering has been applied to keep the rotors spinning slowly. Changing the blade pitch is the most common way to regulating the speed and all the big turbines have a "cut-out" speed where a braking system actually stops the rotor from spinning too fast in high winds.
Slow rotors last longer, are quieter, and pose a much lower risk to birds. The other turbines in the video are Vestas v82s which are much larger than the Zonds on Buffalo Ridge but themselves are dwarfed by the 126 meter rotors on the new 5 megawatt giants.
This video shows the assembly of a v82 Vestas. It is roughly 1/2 the size of a new 5 MW turbine.