Thursday, November 8, 2012

Believe it or not: world's longest turbine blade

When Dee saw this headline she was so impressed she whipped out a quick BION post, which means I have Thursday off!  Thanks, Dee! 
Siemens, a manufacturer out of Germany, has found a reason to build this incredibly large off-shore wind turbine, and has plans to build a total of 300. This reminds me of something my brothers would have enjoyed working on as kids. The blades on these puppies are incredibly large (75 meters) that’s equivalent to just over 246 feet. 
Hummm, to put this into prospective let’s just say the blades are about the same size of 2 and a half football fields, 1 and a half Olympic size swimming pools or almost three times the height (at its highest point) of the Golden Gate bridge. Now, double that for a whopping 154 meter span but still weights less than more typically produced blades by using lightweight materials during construction. The entire blade is made of a single piece of “glass fiber-reinforced epoxy resin and balsa wood”. Balsa wood? Yes, that’s right, balsa wood.
Not knowing my wood that well, I had to look up what the heck balsa wood was and if it was a renewable resource. Come to find out it is native to southern Brazil and northern to southern Mexico, but is found in other countries such as Indonesia, Thailand and Papua New Guinea. The best part is that it is a pioneer plant (or as my dad would have said, it’s a volunteer), plants itself in clearings in forests, wither man made or where trees have fallen, or in abandoned agricultural fields. It grows extremely rapidly which explains the lightness of the wood, lower density even than cork, and about 60 percent of the world’s supply comes from balsa plantations that grow it in densely packed patches and harvested after 6-10 years.
Okay, back on track, besides it being lightweight in relation to its size the construction processes also makes the wind turbine extremely strong. A really great asset to have when they will be hit with the energy of about 200-tons of air per second out in the sea!
According to Siemens the tips of the 75 meter long blades will be able to move at up to 80 meters per second or 2.16 mph. So, my mind starts to wonder, why so big? The answer is actually simple. As the turbine blades get longer the amount of electricity they produce increases very rapidly. Because offshore wind projects are quite expensive it makes sense to build a few big wind turbines than lots of small ones.

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