Editor's note" It was an early deadline for Memorial Day. Mike's past column from Aug 4, 2009 is rperinted today.
Once stately, once proud, the old hulk stands as a sentinel, as if waiting to be pressed into a service - long past. It was electric pumps as well as rural water and the long pipes laid in the ground that invited its demise and caused it to be left unattended to the elements.? Now vaneless, tailless, and idle, the old windmill, or what's left of it seems diminutive in the shadow of the new wind turbines dotting the landscape. The landscape is changing; a new era, new technology has finally sealed the ancient windmill's fate. Although now derelict, it may well stand for another century as testimony to what once was.?
The power of the wind has always been available to Iowans willing to build a mechanism to harvest the power. Once, nearly every country homestead had a windmill.?The wind turned vanes which turned a shaft that coupled to a pump. Sometimes the coupling was done in ingenious ways.? Some used hand pumps which rode up and down with the action of the wind, pumping water into troughs for cattle to drink.?A little grease on the moving parts, an occasional tightening of the parts, and infrequent coats of paint and the old windmills kept working and working. Now considered obsolete and unnecessary, most suffer the same fate slow death by rust and corrosion.?
I'm not sure the sight of hundreds of towering monopoles with slow moving blades will ever be taken for granted like the old windmills were.? ?
Even the vernacular is changing.?The new machines, and all those which use the power of the wind to generate electricity are called wind turbines.?The old ones, used to pump water or grind grain are called windmills. Call those new fangled devices windmills and you've misspoke.? ?
The individual demise of the old windmills went something like this:?While connected to a pump or other load, even in a fierce wind, the rotational speed of the vanes was limited by the load. Once the mechanical linkage was broken, through corrosion or deliberate disconnection, the windmill was destined to freewheel.?Once it was able to freewheel, the force of a strong wind caused the vanes to overspeed, and self-destruction was only a matter of time. The bases of these old windmills become a collection point for various bits and pieces of what once was a usable mechanical device. The term freewheeling has evolved to mean heedless of consequences or carefree. In the life of a windmill, it means certain death.?
The new wind turbines are amazing collections of high tech computers and controls. The pitch of the blades can be changed while in motion and the blades can be rotated into the wind for optimum angles. Engineering has solved the problem of freewheeling. As long as there is a slight breeze, these devices are on-line and producing.?
I'd wager no farmer even 20 years ago knew what the term Betz Coefficient meant or that it is 59.3 percent. This is the theoretical maximum efficiency at which a wind generator can operate, by slowing the wind down. If the wind generator slows the wind down too much, air piles up in front of the blades and is not used for extracting energy.?
Iowans had their first major taste of Alternative Energy, a popular term for "non-conventional," usually renewable energy in the form of ethanol produced from corn.?There is also a surge in the production of agricultural based biofuels such as biodiesel happening in Iowa right now. It's almost as if Iowa has become a new hub of technology centered on production of energy from renewable sources.?
Wind energy is the next storm of technology which is rapidly changing the landscape in certain parts of the state. On a couple different trips recently I was able to see this new technology in action on a grand scale.?
This week while making a trip to Minneapolis for my business, I traveled Interstate 35.? In northern Iowa you can see literally scores of these behemoths from the highway. It really is a spectacular, if not eerie sight.?On a recent trip to Omaha, along Interstate 80, similar wind farms dot the landscape.?
The depth of the technology makes the old windmill technology pale in comparison. These new beasts are 26 stories high. The blades are as wide as the wings of a jumbo jet and weight about 8000 pounds. There are 3 of them on each tower turning at an optimum speed of 20 revolutions per minute; far slower than the runaway speed of the old fashioned windmills.?A mere 8 mile per hour wind is required for them to "harvest" energy.? Each of them individually generates enough power for approximately 750 people.?
Iowa is on the cusp of being a technology leader in the generation of electric power and other energy sources. The landscape is changing, as are our fortunes.?Our universities have created entire divisions to study and teach these new technologies. Either you are along for the ride, or part of the revolution.?In any event, change is coming, and the countryside is changing in ways grandpa would never have imagined.
In to the Wind and this column are copyright 2009 Mike Gilchrist. Readers, feel free to contact me at email@example.com via email, or write to me at P.O. Box 255, Toledo, IA? 52342.