Wind Project Performance 1994 Summary

Domestic and Foreign Turbines

Wind Figure 14

By the end of 1994, foreign turbine capacity was 867 MW, compared to 742 MW of domestic turbine capacity. During 1994, 40.2 MW of domestic and 14.1 MW of foreign turbine capacity was installed (Figure 14 -- Capacity by Turbine Origin).

Wind Figure 15

A comparison of capacity distribution for domestic and foreign turbines in 1985 and 1994 is shown below in Figure 15 (Capacity Distribution by Origin, 1985 and 1994). For a more complete historical perspective, cumulative and new capacity for domestic and foreign turbines is shown in Table 2, below.

1985-1994 Capacity Distribution By Turbine Origin
Domestic (%) Foreign (%)
Cum. New Cum. New
1985 67 55 33 45
1986 55 25 45 75
1987 56 49 44 51
1988 58 87 42 13
1989 52 17 48 83
1990 53 45 47 55
1991 46 4 54 96
1992 47 39 53 61
1993 45 58 55 42
1994 46 74 54 26

Wind Figure 16

Capacity factor results indicate that overall performance of foreign turbines (26 percent) exceeds domestic turbines (19 percent). Both domestic and foreign turbine bases benefit from the inclusion of newer, more efficient machines. Historically, the domestic turbine base has been more adversely affected by older, less efficient turbines. When turbines installed since 1985 are isolated, the performance gap narrows. The capacity factor for domestic turbines increases from 19 percent to 24 percent, while foreign turbines increases from 26 percent to 27 percent (Figure 16 -- Capacity Factor by Origin). The improvement in capacity factor for domestic turbines may result from the retirement of old turbines with poor performance and the addition of newer, more effficient turbine stock.

Wind Figure 17

The impact of other variables on domestic turbine performance is demonstrated by two large projects in the Altamont resource area with more than 148 MW of turbine capacity and an average capacity factor of only 11 percent. Domestic turbines account for 103 MW of the 148 MW capacity with only a 6 percent capacity factor. When these two projects are eliminated from the domestic turbine base, the adjusted capacity factor increases to 21 percent (Figure 17 --Adjusted Capacity Factor for Domestic Turbines).

Wind Figure 18

Analysis of kWh per square meter performance data indicates that foreign turbine performance (854) is about 18 percent higher than domestic turbines (723) without any adjustments (Figure 18 -- kWh Per Square Meter Production by Turbine Origin). It should be noted that when newer turbines installed since 1985 are isolated, kWh per square meter production for both domestic and foreign turbines normally increases. However, 1994 data indicate a decrease in kWh per square meter production for domestic turbines installed since 1985. It should be noted that this decrease may result from reporting limitations rather than lower performance. (See Footnote 3.)

As a general rule, the kWh per square meter measure is comparatively better than the capacity factor measure when evaluating domestic turbine performance. This is because overstated capacity ratings for older domestic turbines appear to significantly reduce capacity factor performance.


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