Wind Turbines - Wind Energy: Renewable Energy and the Environment - page 87

TABLE 5.1
Calculated Annual Energy Production for 1 MW Wind Turbine in the Panhandle of Texas

Wind Speed
m/s

Power
kW

Bin Hours
h

Energy
kWh

1 0 119 0

2 0 378 0

3 0 594 0

4 0 760 171

5 34 868 29,538

6 103 914 94,060

7 193 904 174,281

8 308 847 260,760

9 446 756 337,167

10 595 647 384,658

11 748 531 396,855

12 874 419 366,502

13 976 319 311,379

14 1,000 234 233,943

15 1,000 166 165,690

16 1,000 113 113,369

17 1,000 75 74,983

18 1,000 48 47,964

19 1,000 30 29,684

1,000 40 39,540

q20

25 0 0

8,760 3,060,545

Availability is the time that the wind turbine is in operational mode, and it does not depend
on whether the wind is blowing. Availability is related to reliability of the wind turbine, which is
affected by both the quality of the turbine and operation and maintenance. Experimental values of
availability of wind turbines in the field were poor for first production models; however, availabili-
ties of 98% are now reported for later units, which have a good program of ongoing maintenance.
Remember, a wind turbine does not have problems when the wind is not blowing. Therefore, preven-
tive maintenance is imperative to maintain energy production.
Calculation of estimated energy production is simple using spreadsheets or by writing a program
to do the calculation from a histogram and a power curve. The data would be in tabular form and
can be graphed using spreadsheets or generic plot programs. Spreadsheets for calculation of energy
production are available at the accompanying website for Renewable Energy and the Environment.

5.9 INNOVATIVE WIND SYSTEMS
Innovative or unusual wind systems ( Figure 5.17 ) have to be evaluated in the same way as other wind
turbines. The important categories are system performance, structural requirements, and quantity and
characteristics of materials. Innovative ideas include the tornado type, tethered units to reach the high
winds of the jet stream, tall tower to use rising air, tall tower and humid air, torsion flutter, electrofluid,
diffuser augmented, the Magnus effect, and others. Many of these have been reported in Popular Science
[2-4]. Most all innovative concepts remain at the feasibility or lab experiment stage. Not all innovative
systems are recent inventions; for example, sail wings, wings on railroad cars, and the Magnus effect
(Madaras concept was rotating cylinders on railroad cars) have been around for a long time.