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Farming Wind - setting up a MET (meteorological test) tower

April, 2010

 

All Photos Copyright © 2010 by Robert E Pence

 

 

Wind Capital Group has initiated development of a wind farm in Wells County, Indiana. They have secured enough acreage under lease to proceed with the project and are setting up MET (Meteorological Testing) towers to track wind direction and velocity and other atmospheric conditions in order to most effecitvely site turbines. They plan to use 1.5 megawatt turbines in this project.

 

One of the 60-meter-tall towers is sited on farmland owned by by brother, David, and me. The 60-meter height puts them just under the 200-foot limit that requires lights to warn aircraft. On Satuday, April 17, 2010, we took a look at what the setup crew was doing. At that point, they predicted that the tower would be pulled upright about Wednesday.

 

Saturday, April 17, 2010: It's a good hike through corn stubble from the arched white barn to the tower site, so we drove:

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David's latest toy, a Ford 8700 Diesel from about 1978

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[url=http://www.nationalwindassessments.com/">National Wind Assessments</a> set up the tower. The area is flat and wide open, and every year more woodlots get turned into corn-and-soybean acreage. The temperature was in the mid-40s (Fahrenheit), and one of the setup guys commented on how windy it is out there. I reminded him that the peristent wind is why he's there.

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The tower's guy wires will be marked with the yellow tubes and orange globes to make them highly visible to farm machinery operators.

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The tower is made up of sections of galvanized steel tubing that fit one insde the other, like a stovepipe. It's mounted to a hinged base and secured by guy wires fastened to soil anchors. The tower is being assembled on the ground, and will be pulled upright using a gin pole.

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Wednesday, April 21, 2010: Instruments are attached and they're ready to pull the tower upright using a gin pole and a 12-volt electric winch.

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Adding a temperature sensor.

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One man controlls the winch, and the other two crew members are where the guy wires attach to soil anchors. They communicate with walkie-talkes, and make adjustments to keep the tower straight and the guy wires at the proper tension. It's a slow process, raising the tower a few degrees and then adjusting the guy wires.

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Going Up!

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My attention wandered, and I took a photo of the former Henry Dunwiddie round barn. It's undergoing demolition by neglect; there are holes in the roof, and the cupola already has collapsed in on itself. Round barns often are stick-built, and unlike a mortise-and-tenon pegged timber structure, it doesn't take long for them to fail when the roof goes bad and lets rainwater in.

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Almost there.

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It took about an hour to get to this point. I left, but from the sawmill I could see that the crew still was working for quite a while on fine-tuning the guy wire tension.

Pretty interesting.  I can't get over how flat it is out there.  Living in Pennsylvania, I'm used to seeing rolling hills everywhere I look.

My parents are taking a cross country trip to Oregon right now and they told me they went through a huge wind farm in Iowa.  That tower looks so slender for being almost 200 feet tall. 

Neat!

"You don't just walk into a bar and mix it up by calling a girl fat" - buildingcincinnati speaking about new forumers

Pretty interesting.  I can't get over how flat it is out there.  Living in Pennsylvania, I'm used to seeing rolling hills everywhere I look.

My parents are taking a cross country trip to Oregon right now and they told me they went through a huge wind farm in Iowa.  That tower looks so slender for being almost 200 feet tall. 

 

The tower will be stabilized by guy wires at multiple levels. The slender design has two benefits that I can think of; it minimizes surface exposure to high wind pressures, and minimizes the wake or slipstream that might affect the instruments. Anemometers willl be placed at two or three different levels on booms that extend out from the tower five or six feet, in order to get them as far as possible from the tower's wake. The tower will report meteorological data periodically via cell phone.

 

I don't know what size turbines they use in Iowa. Wells Prairie will get 1.5 megawatt units. On those, the nacelle is about 260 feet up and the blades are 130 feet long. That puts the top of the rotor's arc at about 390 feet. The ones in Wood County, Ohio, outside Bowling Green, are 1.8 megawatt units, and on a clear blue-sky day you can see the tips of the rotors above the trees for quite a distance. I think I clocked it at almost seven miles once, from first sighting on the horizon.

 

I did a little rough estimating from the stats on the 1.8mw turbines, and at full output the shaft horspower generated by the rotor appears to be roughly 2,800 based on a guess at about 85 percent mechanical and electrical efficiency from the dynamo and drive train.

 

One of my Air Force buddies in the detachment at IU in Bloomington used to come home with me sometimes on weekends. He was from Renovo (railroad family), and he said he had never lived anyplace where he could see more than a quarter mile in any direction. He thought the spaciousness of our flat farmland was incredibly beautiful in summer.

Added the rest of the photos from Wednesday, when they stood the tower up.

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