A couple of days ago, I noted the efforts of startups in this country and others to manufacture a windmill that would fit on a roof, balcony or porch of a person’s home. These are admirable efforts, but because the products are manufactured using fossil fuels and shipped long distances, they unfortunately come with a significant energy deficit attached. Any energy generation will have to be significant enough to erase that deficit before it will become helpful to the environment. If your motivation for using a windmill to generate electricity is to save money, the money you save will have to be greater than the money you spent on the windmill, too.
A solution to the environmental and economic costs of production and shipping is to make your own windmill. And while you could get your materials from a hardware store that also gets its materials from China or some other far off place, the cheapest and most environmentally friendly approach is to use local materials obtained from the leftovers of another project of yours, or from a junkyard or landfill.
Here are some ideas on how to build your own windmill:
Scoraig Wind gets into loads of detail and looks useful for those who have or have access to a good machine shop. In fact, it is so comprehensive that it is a bit intimidating. Hugh at Scoraig apparently spends quite a bit of time teaching people how to build their own windmills in detailed workshops.
Kevin Harris also provides useful detail and stresses simplicity and that yes, you CAN do this with just a handful of parts and tools.
Ted Baer gives inspiration and some details (but I can’t find a complete parts list) for the construction of a windmill using an old bicycle wheel and aluminum house siding scraps.
Bob Hunckler also suggests using a bicycle wheel, and has a really great attitude about experimentation, suggesting that you go with what works for you and plug your ears when some engineer comes by and tells you that you’ve really screwed up your drag coefficient and need to use a curved blade with a cosine function of blah blah blah. The big picture is that you’re generating electricity without sucking up carbon, not angling for an A in a class project.
Mike Davis tells a great story about making his windmill generator on the cheap with an advisory tale:
I never got a chance to properly test the unit before heading to Arizona. One windy day though, I did take the head outside and hold it high up in the air above my head into the wind just to see if the blades would spin it as well as I had hoped. Spin it they did. In a matter of a few seconds it spun up to a truly scary speed (no load on the generator), and I found myself holding onto a giant, spinning, whirligig of death, with no idea how to put it down without getting myself chopped to bits. Fortunately, I did eventually manage to turn it out of the wind and slow it down to a non-lethal speed. I won’t make that mistake again.
The story ends up with Mike going camping with his portable windmill and an array of his favorite electronic gadgets and DVD-playing computer. This is a project for the handy, not for the faint of heart. But yes, it can be done.