[Seany (OP)]

Well.. I see windmills... And they are huge things!!

I think they are made of metal, but I may be wrong..

But by looking at it, it seems really really heavy!!

Even on a very "not-windy", just a slight breezy day, the windmill spins really fast!!

Do they use some electricity to keep it going? But less than what it is producing, so that they still gain energy? Or.. Is it actually the wind doing it?

[DoctorBeaver]

It's the wind. There would be no point using electricity to turn the windmill to produce less electricity than it takes to turn the blades.

[Karen W.]

Definitely the wind I want one in my yard Electric company would pay me to use extra power from the windmill plus I would never have and electric bill again..YAAYYYYYYYY Mine run 600.00 dollars a month! Awful power bills!


They can be made from wood or metal.. they can be quiet or quite noise.. but they can produce a lot of energy that you would then be storing in batteries like solar panels and batteries. You can power your home with them..pretty easily dependent on your normal wind conditions..

[another_someone]

Not sure how much it is metal, and how much plastics - I would suspect the latter (concrete posts, but plastic aerofoils).

Yes, they are heavy, but the whole point is that by being large, they can also create a lot of lift that will thus be able to move themselves even with relatively light winds.

The problem with windmills is often not about getting them to move under light winds, but getting them to move over a wide range of winds.  In an area where one gets lots of heavy winds, if you build a windmill that can easily move in light winds, will have to be shut down when the wind gets too strong, and risk damaging the windmill.  If you build a windmill to take advantage of strong winds, it may not be able to function efficiently under light winds.

Windmills never consume energy (except in their construction).  If the wind is not at an appropriate strength to drive the windmill efficiently, the windmill will simply be feathered, and shut down.

[daveshorts]

From pictures of Auzzie wind mills that Ali (who used to work for us) had, the columns are steel tubes, I am not sure if the blades are made of metal or possibly a composite to make them lighter, or possibly more importantly thinner - looking at the web there definitely are fibreglass blades out there. Either way the blade assembley will have it's centre of mass inside the axel, so as it turns you are not moving weight up or down, so even though the whole thing weighs many tonnes, as long as you have enough force to overcome friction it will spin.