Why We Have No Wind or Solar Power

[Frank Lee]

Stupid $15 facilities charge is half my bill!

[Concrete]

Frank,

yes that is stupid
the "facilities charge" should be pro rated per kWh

like I said before
I would be happy if we could just stop distorting the market
that is a rather regressive system that almost subsidizes non conservation

you just got notice?
is the rate set for sure or is just set to go for approval?
(around here you usually get a shot a contesting such moves before the are set in motion)

[Big Dave]

"Facility charge" or the same thing by other names reflect the fixed charge of power T&D regardless of usage. That transformer and transmission line cost exactly the same whether you use zeo kwh or up tro the capacity of the line. Actaully the 240 volt residential service is an expensive way to transmit power. Generally the higher the voltage at which you recive the power the less T&D losses are incurred. Big users receive power at high voltage (often 13.2 kv) and have their own substations, and thus the did not get billed for a "facility charge."

On the macro scale, wind, solar, and geothermal electrucity are penned into limited geographical areas simply because that's where they are. Maybe (with a massivel augmented T&D infrastructure) the parts of America west of the 100 meridian maybe could be substantially powered by solar (roof over Nevada and Arizona), wind (the Front Range Ridge is an awesome potential resource) and geothermal (Yellowstone alone could be substantial).

But solar in South Bend? Wind in the Ohio Valley? Aintgonnahappen.com

[PA32R]

Originally Posted by trebuchet03

It's worth pointing out that these large bladed designs have really high tip velocities.... Which leads to an unfortunate limitation of scale as you get nearer to the sound barrier.

High Altitude It's the future

At 28.8 r.p.m. you can have a blade diameter of almost 110 meters and have a tip speed of less then mach 0.5. That's a pretty big fan. I suspect stresses might be a problem on a thin airfoil 54 meters long. The A380 wingspan is
not quite 80 meters, so the wing itself might be about 37 meters. I'm not sure about the stress calculations for a wind turbine blade, but I'm guessing that that's the limiting factor. From what I can see googling around, it looks like 100 meter turbines with 49 meter blades are the upper end at this time. Tip speed would be well below mach 0.5 at 28.8 r.p.m.

Here is a picture of a huge turbine with rotor diameter of 126 meters and blade length of 61.5 meters. At 28.8 r.p.m, the tip speed would be about 190 meters/second or a little under mach 0.6. Transonic speed is considered to begin at mach 0.8. So, there is some room to grow.

[MechEngVT]

Originally Posted by PA32R

At 28.8 r.p.m. you can have a blade diameter of almost 110 meters and have a tip speed of less then mach 0.5. That's a pretty big fan. I suspect stresses might be a problem on a thin airfoil 54 meters long. The A380 wingspan is
not quite 80 meters, so the wing itself might be about 37 meters. I'm not sure about the stress calculations for a wind turbine blade, but I'm guessing that that's the limiting factor. From what I can see googling around, it looks like 100 meter turbines with 49 meter blades are the upper end at this time. Tip speed would be well below mach 0.5 at 28.8 r.p.m.

Here is a picture of a huge turbine with rotor diameter of 126 meters and blade length of 61.5 meters. At 28.8 r.p.m, the tip speed would be about 190 meters/second or a little under mach 0.6. Transonic speed is considered to begin at mach 0.8. So, there is some room to grow.

But compressibility effects in fluid dynamics begin to become significant at or below M0.3 IIRC from my own courses in turbomachinery design and fluid dynamics.

Your aircraft wingspan analogy ignores that in an airplane the lifting force is roughly perpendicular to the direction of motion whereas in a turbine the lift force is tangential to the direction of motion. This has significant influence on the available cross-sections to resist the bending moment. A turbine blade can have a much larger supporting base in the direction of loading to improve its section modulus without negatively impacting its drag ratio. This is simply not as practical in aircraft.

[Big Dave]

How much loss in efficiency of your wind turbine is a bird worth?

[Concrete]

Dave,
I'm confused
in this case the larger wind turbines are:
more powerful
more efficient
more cost effective
and less likely to kill birds

not sure I understand your question
and I know you are not advocating chopping down turbines because of government regulations on birds

[Big Dave]

They may or may not be improved but they are still subject to project-delay lawsuits.

[Concrete]

Dave,

I think birds are yesterdays lawsuit
the tree-huggers have moved on to bats

Bats More At Risk From Wind Turbines Than Birds, Study Claims : TreeHugger

you know, all kidding aside
the tree huggers have harassed all the renewable sources of power

The cartoon that started this thread was a joke that "the man" stops renewable energy
but your point Dave is a documented fact:
tree huggers are as responsible as any faction for "Why we have no wind or solar power"

[Duffman]

This was timely, people in high places think this is a potential problem.

Gas pipelines vulnerable to terrorism: expert : Home : News : Sympatico / MSN