I was under the impression that small wind generators at the scale of suburban backyards are really uneconomical and don't produce sufficient energy for anything of practical use.
small wind turbines are also horrendously unreliable because of mechanical failure. Same logic as to why pickup trucks are generally more reliable than a smart car.
Laws of physics: maximum power that can be generated is proportional to the swept area of the blades. So it scales exponentially as blade length increases.
Unfortunately I can no longer edit the post, but of course you’re right. Max generated power is proportional to (blade length)^2, therefore quadratic, not exponential.
I assumed that meant that big windmills would be much cheaper per watt than small ones, but according to what I'm finding in https://news.ycombinator.com/item?id=44056971, that doesn't seem to be the case. Small rooftop windmills may actually be cheaper!
There’s another limiting factor though, which is that power is also proportional to (wind speed)^3, and the wind is greater higher up.
Although having said that, I do believe the main reasons we don’t use them in the UK are noise and wildlife concerns. In many ways the total efficiency doesn’t matter if it’s generating enough power.
Yes, so it's puzzling that the small windmills (necessarily designed for low wind speeds) cost less per peak watt. You'd think getting more power per square meter higher up would reduce the cost per peak watt. Wind speeds are more consistent up there, too.
The wildlife concerns are completely specious. The main reason you don't use them in the UK are that the wrong sort of people have political power.
