Thursday, January 14, 2010

Whoa, they're big

Those wind turbines popping up across the U.S., sometimes singly and but more often in “wind farms,” are larger than one might first think. Seen from a passing vehicle, headed south on I-65 toward Purdue near Wolcott, Ind., for example, the slowly and gracefully turning rotors bely the true size of these power producers.
A little investigation turned up some interesting information about this technology. Commercial scale wind turbines only operate at wind speeds of 11 mph or greater. Typically they are mounted 100 ft or more above the ground, which lets them take advantage of the faster and less turbulent wind at that height. Taller towers sometimes use rotors having a diameter of more than 300 feet.
Each typically generates a megawatt or more of electrical energy. Where wind farms can be connected to the electrical grid, they can contribute significantly to our electrical power needs.

We came across this Department of Energy photo that shows one completed tower, another where the rotor is being lifted into place, and a few people, a big crane, and a pickup truck to help show the scale. Each of the blades is 118 ft long. It's at the Red Hills Wind Farm in Oklahoma. Just in case the photo's missing, here's the link: http://www.nrel.gov/data/pix/Jpegs/16483.jpg (Photo by Todd Spink, courtesy of DOE/NREL.)
Refreshed URL for the image (with explanation), Oct 30, 2015: http://images.nrel.gov/viewphoto.php?imageId=6311868

Thursday, December 3, 2009

The Expedition

We gathered a very few miles from the state line early Friday morning, the day after Thanksgiving, for our traditional hunt for the perfect Christmas tree. It was uneventful until we got home and prepared to unload the tree, which had been lashed to the luggage rack.
Focused on grabbing my gloves from the back of the car, I leaned forward on the last stride.

Noticing that the raised hatch was bending the top of the tree, he began to close it.

Physics set in, and then biology (or was it physiology?) Two objects cannot occupy the same space at the same time. Head wounds bleed.

I stop, suddenly, then stagger backward, several slow steps. Later, he can't stop laughing as he imitates my slow, crouching, backward stagger. Neither can I.

I feel my head. A shallow groove in the skin, the image of a trench. No puncture, no slice. A formed depression, and it's wet. Yep, my fingers are bright red.

After the bleeding has slowed to an ooze, they take turns looking at the wound as I help part my hair around it. I don't think you need stitches, she says. That's good news, because just the thought of that hurts. You could use a butterfly bandage, he says, and I start laughing again. Would it stick to all the hair? Or require a shave?

Laughter is great medicine; the healing begins.