Chapter 4.1: Over all Performace

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Of course the output is entirely dependant on the wind available.  The  Ontario Government has these two maps of wind speed in the Province (see)
 

 

Of course, this is over all for the year, and obviously, as you will see below and in subsequent chapters, changes radically in the summer from “optimal” performance. 

The over all wind output on a percent Hourly Capacity Factor vs number of hours for all turbines looks like this:   

   

Not all the wind farms started at the same time.  This is the beginning time and number of records used to make that graph.


  

 
WindFarm Capacity MinOfDate MaxOfDate CountOfHour
AMARANTH 200 01-Mar-2006 26-Aug-2010 39360
KINGSBRIDGE 40 01-Mar-2006 26-Aug-2010 39360
PORT ALMA 101 19-Jul-2008 26-Aug-2010 18456
PORT BURWELL 99 20-May-2006 26-Aug-2010 37440
PRINCEFARM 189 08-Oct-2006 26-Aug-2010 34056
RIPLEY SOUTH 76 02-Dec-2007 26-Aug-2010 23976
UNDERWOODWGS 182 29-Nov-2008 26-Aug-2010 15264
WOLFE ISLAND 198 13-May-2009 26-Aug-2010 11304

The plot only uses the number of hours of existing data to get the Hourly Capacity Factor, including hours of no output.   

Notice the large number of hours of no output.  At 15.8% of the hours it dominates the plot.  The next column (between .09 and 1.0 % name plate) which is the second largest number of hours, is a mere 3.9% of the hours.   

You can clearly see that the average, what the industry uses for Capacity Factor, has no physical meaning on this plot.  It’s not in the middle, it’s not exceptional, it’s not unique in any way.  It’s just a calculation of the average.   

The median, however, is the point where half the hours are below that value.  Overall then, the median of 14% means this:  Fifty percent of the time output from wind in Ontario is less than 15% name plate.  Half the time the output is 14% OR LESS. From this point on this point will be referred to as the Median Capacity Factor.   

The other significant number here is the Standard Deviation.  65% of all values are in the first Standard Deviation noted on the graph.  That number is the Median plus the Standard Deviation of 27.4%.     

Skewness is a complex calculation (see), but important number because it tells us how far the median is from the average.  Consider it the “pull” on the bell curve in one direction.  A positive number is to the left, towards smaller percent of name plate.  If the skewness was negative, the median would be to the right of the average, more into the high percent of name plate.   

This graph shows the changes in the Capacity Factor (not the Median Capacity Factor) for all the farms over each month.  The Median Capacity Factor (where 50% of the time output is lower) is about half these numbers.  

  

Notice the significant drop off in Capacity Factor during the summer months.  Fall 2009 to 2010 was a particularly low year for wind production.  

  

This graph is the Median Capacity Factor for each month for each farm.  The summers clearly show very low MCF below 10% for almost all the farms.   In the summer time, all the farms half the time produce less than 10% name plate.  Notice some of the winter months come very close to the Capacity Factor, which will show up as near zero skewness for that month.  

  

This plot of skewness per farm per month is the opposite of the above graphs.  Very low skewness in the winter months, but very high skewness in the summer.  This means that in the summer time the use of Capacity factor is further away from actual output.  The spread of the output for each month, the range of the Hourly Percent Name Plate, is the Standard Deviation.  

  

Notice that the range of values is much more spread out in the winter (higher SD) than in the summer.  

So summers tend to be small MCF, with high skewness and narrow range of hourly percent name plate output, while winters tend to be higher MCF, with low skewness (closer to the CF), but with a very wide range of hourly name plate values (thus more intermittent and with unpredictable swings than in the summer).  

This is the data that produced the top graph:

HCF Count Of Hours Accum Hours % of the time
0 34634        34,634 15.8%
1 7790        42,424 19.4%
2 9206        51,630 23.6%
3 6002        57,632 26.3%
4 4798        62,430 28.5%
5 6830        69,260 31.6%
6 5036        74,296 33.9%
7 6247        80,543 36.7%
8 3678        84,221 38.4%
9 3828        88,049 40.2%
10 5411        93,460 42.6%
11 3697        97,157 44.3%
12 4391       101,548 46.3%
13 3491       105,039 47.9%
14 3154       108,193 49.4%
15 4365       112,558 51.3%
16 2354       114,912 52.4%
17 4017       118,929 54.3%
18 2434       121,363 55.4%
19 2659       124,022 56.6%
20 3195       127,217 58.0%
21 2351       129,568 59.1%
22 3234       132,802 60.6%
23 2223       135,025 61.6%
24 1826       136,851 62.4%
25 3065       139,916 63.8%
26 1958       141,874 64.7%
27 2551       144,425 65.9%
28 2074       146,499 66.8%
29 1330       147,829 67.4%
30 2699       150,528 68.7%
31 1751       152,279 69.5%
32 2575       154,854 70.6%
33 1103       155,957 71.1%
34 1411       157,368 71.8%
35 2065       159,433 72.7%
36 1124       160,557 73.2%
37 1792       162,349 74.1%
38 1118       163,467 74.6%
39 1181       164,648 75.1%
40 1750       166,398 75.9%
41 893       167,291 76.3%
42 1764       169,055 77.1%
43 1021       170,076 77.6%
44 993       171,069 78.0%
45 1302       172,371 78.6%
46 950       173,321 79.1%
47 1506       174,827 79.8%
48 855       175,682 80.1%
49 620       176,302 80.4%
50 1422       177,724 81.1%
51 938       178,662 81.5%
52 1425       180,087 82.2%
53 800       180,887 82.5%
54 540       181,427 82.8%
55 1231       182,658 83.3%
56 800       183,458 83.7%
57 1283       184,741 84.3%
58 554       185,295 84.5%
59 738       186,033 84.9%
60 1184       187,217 85.4%
61 710       187,927 85.7%
62 1064       188,991 86.2%
63 628       189,619 86.5%
64 677       190,296 86.8%
65 1125       191,421 87.3%
66 541       191,962 87.6%
67 1111       193,073 88.1%
68 662       193,735 88.4%
69 634       194,369 88.7%
70 871       195,240 89.1%
71 651       195,891 89.4%
72 1025       196,916 89.8%
73 698       197,614 90.1%
74 511       198,125 90.4%
75 1126       199,251 90.9%
76 670       199,921 91.2%
77 1017       200,938 91.7%
78 641       201,579 92.0%
79 484       202,063 92.2%
80 1116       203,179 92.7%
81 608       203,787 93.0%
82 1155       204,942 93.5%
83 459       205,401 93.7%
84 594       205,995 94.0%
85 1297       207,292 94.6%
86 687       207,979 94.9%
87 1143       209,122 95.4%
88 700       209,822 95.7%
89 776       210,598 96.1%
90 1606       212,204 96.8%
91 639       212,843 97.1%
92 1990       214,833 98.0%
93 873       215,706 98.4%
94 767       216,473 98.7%
95 1048       217,521 99.2%
96 703       218,224 99.5%
97 422       218,646 99.7%
98 568       219,214 100.0%
99 0       219,214 100.0%
100 1       219,215 100.0%

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