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Re: floating Windmills

Following a link to the root website is even more inspiring. Turbines cantilevered from the tower. Amazing how they stay horizontal despite having a large amount of weight being held by such a slender tube.

I have been out of touch with materials. Have they gotten this good yet?

Just think of the eccentric load that can happen with that shaft. My washing machine does a reasonable jobs of stopping to rebalance the load, but it can say "STOP!".

Why is it that you are frowned upon if you suggest that someones fantastical dream reached beyond the realm of reality.

I know, I have the wrong attitude.

Re: floating Windmills

Hang on Brad, they may be on to something here.

I could see fitting a small scale version of that concept to the roof on my car that, connected to a battery, could give me free electricity every time I drive!

Wow. Think of the savings!

In fact if I bought a Prius I could probably run it hardly using the petrol engine. And when the Prius's battery packs fail after 4 years and are too expensive to replace I can revert to the engine and just use the electricity from the roof turbines once I am moving! Excellent.

Hopefully after 7 years or so, when the entire Prius power system needs replacing at a cost greater than the value of the car, someone might have improved battery technology enough to allow high capacity nuclear charged units to power electrical appliances for extended periods. So I expect some clever person will have worked out how I can convert my roof turbines so that can be used as a powersource (I guess just connect them to the battery with opposite polarity?) and they can replace my missing battery packs and engine. After all, absent powerpacks and engine the Prius will be much lighter than before ...

I can't think of a better investment really, although the brochure I received recently about Flying Pig Power may have some merit. (So long as you don't live near Pirbright.)


Grant

Re: floating Windmills

Newton’s third law of motion also applies to torque.

Re: floating Windmills

What if we use counter-rotating wind mills, like some helicopters do?

Re: floating Windmills

Yes, but helicopters are not long, thin and flexible; and they do not have to deliver electrical power along the same axis. I look forward to seeing your design sketches.

Re: Re: floating Windmills

I was trying to do some back on the envelope stuff and started falling on my face.

This was for one of those flying windmills that hover at 15000 ft to 30000 ft.

Using aluminum wire, and a 10MW generator, it seems that you need to have a 1 in diameter wire and a 8KV Generator and you will heat the wire with 5% of the electricity.

The weight of the 1" wire at 30000 ft is about 36000 lb.

If the turbines are spinning in the wind, and supporting this 36000 lbs, we need to keep that 36000 lbs aloft before we start generating electricity.

We are flirting with the tensile strength of aluminum (our safety factor at this weight is less than 3.

I was trying to guesstimate the windspeed necessary to keep the turbines spining fast enough to keep the generators aloft.

Re: Re: Re: floating Windmills

Attacking this problem from a different angle might shed light on why these things aren't flying yet.

5 years ago, the wholesale rate for electricity was about $30/MW-hour.

If an Flying electric generator were able to get aloft a 1 MW version and maintain 60% availability, it would generate about $160,000 / year.

Considering these are actually, little more than helicopters, the economics of helicopters probably still apply. You do need to pay the mechanic to maintain them, and helicopters need a lot of maintenance.

I suspect that the reason these aren't flying over every available piece of jetstream is that it is not economical to do so. It has the appearance of being free, but the realities bite them in the rear.

One of the proposed projects is 45000 lbs.

So would it be wrong of me to suggest that the amount of current you need to send to the helicopter to get it airborne is 4 times what you could expect getting back from it, when the motors turn into generators.

I remember seeing a transformer for a 700 MW power plant. It was the spare. It was the size of a small house and took Three Phase 480 V up to 48,000V. I also remember friends making shocking devices that turned a 9V battery into 14,000 V which they would hang on doors.

Can you make a transformer for a 1 MW generator light enough to step up the generator current on the generation side and step in down on the motor side of the equation to fit on the helicopter/generator.