I read in Prairie Business, a monthly regional magazine, that the only place in the USA which makes the blades for these things is in Grand Forks. LM Glasfiber is based in the Netherlands with their American facility here in North Dakota.
AC electric line current, by the way, works on a set frequency. Anything that generates power, whether it be a power plant, wind turbine, or hydroelectric generator, needs to be operating on the same frequency as the power grid. It also needs to be “in sync” with the oscillation of the power grid in order to be connected. If things get out of sync, the grid shuts down to protect itself. So how do you take a farm of 30+ wind turbines and synchronize them to the grid?
On many of the wind turbines you might see around North Dakota, the blade tips pivot to act as a speed brake of sorts. I believe the rotor pitch is also variable, so that the turbine spins at just the right speed to synchronize with the desired frequency. That’s a pretty low-tech way to do it, and requires a lot of mechanical measures to pull it off, so there’s another way…one I think is pretty innovative.
Instead of generating power and pumping it to the grid, while synchronizing to the grid mechanically, some turbines generate DC current and convert it to AC current before putting it into the line. They’re able to synchronize the power they generate electronically, without having to worry about moving parts and mechanical pitfalls. I’m told that the company which came up with this idea is a familiar one: the horrible Enron.
I’m just a layman, but that’s my primitive understanding of wind power in a nutshell. Feel free to correct me or clarify my explanation if you’re more knowledgable about such things. In the mean time, please enjoy the photo!