Posted by Erdemal on April 8, 2007, 12:13 pm
Eeyore wrote:
>
> Erdemal wrote:
>
>> The power of wind varies as the cube of speed
>
> Says who ?
I say :)
Power of a moving fluid
-----------------------
kinetic energy m * v * v / 2
mass per second m = v * area * density
P = k * v * v * v (= cube)
m mass, v = speed, P = power
You could argue too that average wind speed is much higher
at 60 meter height that at ground level.
>
>> so:
>>
>> 54 km/h > 2 MW
>> 25 km/h > 0.250 MW
>> 12 km/h > 0.030 MW (0kW)
>
>
http://www.vestas.com/NR/rdonlyres/662F8438-D741-4128-80A8-B0E72FAB7697/0/V90_3_UK.pdf
>
> Vestas V90-3MW. Looks more like square law to me which is what I'd expect.
>
> 15 m/s > 3MW That's your 54 kph
> 10 m/s > 1.6MW
> 7.5 m/s > 750kW 27 kph
> 5 m/s > 250kW 18 kph (close to the cut in speed)
>
The fan is very probably optimized for a lower speed?
I just want to point out that the annouced power was for
a 'high' wind speed. It's true too that my approximation
was not fair :)
Erdy
Posted by Alex Terrell on April 8, 2007, 11:34 am
On 7 Apr, 23:07, "Hysterical leftwing global warmers must DIE"
> On Apr 7, 5:30 pm, "simple_langu...@yahoo.com"
> >http://www.ez2c.de/ml/solar_land_area/
> You need approx. 40,000 of the largest wind turbines to power a medium
> sized city as well.
> More B.S. anti-nuke, anti-traditional power generation pipe-dreams...
40,000 x 5 MW x 40% = 80 GW.
That's enough electricity for 80 million people. Throw in electric
transport and heating, and you could probably do a City of 30
million.
Medium sized?
Posted by Invasion of the Crackpots on April 7, 2007, 10:25 pm
simple_language@yahoo.com wrote:
http://www.ez2c.de/ml/solar_land_area/
Posted by cyril on April 8, 2007, 11:45 am
On 7 Apr 2007 14:30:57 -0700, "simple_language@yahoo.com"
>http://www.ez2c.de/ml/solar_land_area/
You used PV technology for you projections. For centralized power
generation, solar thermal technology is much better : higer effiency
(more the 20%, reducing the needed area by almost a factor 3),
cheaper, using only conventionnal technology and not needing rare
materials.
Posted by Solar Flaire on June 8, 2007, 4:15 pm
No one solution will be the answer. When the sun doesn't shine, you
have a problem. We need many duplicate systems to cut down on fossil
fuel consumption so we have it when the sun doesn't shine and the wind
doesn't blow and the hydrogen mines close down.
> On 7 Apr 2007 14:30:57 -0700, "simple_language@yahoo.com"
>>http://www.ez2c.de/ml/solar_land_area/
> You used PV technology for you projections. For centralized power
> generation, solar thermal technology is much better : higer effiency
> (more the 20%, reducing the needed area by almost a factor 3),
> cheaper, using only conventionnal technology and not needing rare
> materials.
>
> Erdemal wrote:
>
>> The power of wind varies as the cube of speed
>
> Says who ?