EWT DW-52 500kW: Is the capacity factor for real?

[indy1687]

Hi,

I have being doing a little research on medium wind turbines for a masters thesis. Mainly around the 500kW mark. I have come across a wind turbine produced by EWT in the Netherlands. It is a DW-52. When I look at the power curve data I see that at 9m/s wind speed at the hub it produces roughly 440kW equating to a capacity factor of 88%. Now this seams to be very high when you compare it to a TurboWinds T500-48 or a wind Flow 500. Granted the EWT uses direct drive technology.

Has anyone had any experience with these turbines? Any real world data on these machines? I've looked but it's slim pickings out there...

http://www.ewtinternational.com/wind-turbines/ewt-wind-turbines/dw5254-500kw.html

 

[WindflowNZ]

Hi - the DW-52 (52 m rotor diameter) was originally a 900 kW turbine but it has been derated to 500 kW, probably to get a higher Feed-In tariff rate in the UK. The TurboWinds T500-48 (48 m rotor diameter) was originally a 600 kW turbine but has also been derated slightly to 500 kW predominantly for the same reason. The Windflow 500 has a 33 m rotor diameter (Class 1 - strong winds) or a 45 m rotor diameter (Class 2 - mid-low wind speed). It is very difficult to compare turbine performance (and hence capacity factors) when the rotor diameter and generator sizes are all different. Specific power rating - swept area/generator size (m2/kW) - is a better comparison determinant than capacity factor. Optimisation of rotor/generator size and appropriate capacity factor will come down to whether you want a turbine for a strong wind site or a low wind site.
Depending on what your thesis is about you may find these papers useful.
SITE SPECIFIC OPTIMIZATION OF ROTOR / GENERATOR SIZING OF WIND TURBINES

https://smartech.gatech.edu/bitstream/handle/1853/13971/martin_kirk_a_200612_mast.pdf

Potential for reducing cost of energy by scaling up a low mass turbine

http://www.windflow.co.nz/news/published-papers/NZWEA1999.pdf/view