4.5 Solar Power

The average of monthly values (Table 4.3) show the same general trend as previous solar maps [1, Ch 4]. Solar insolation was measured for horizontal and vertical planes with Li-Cor pyranometers. Monthly values for each site are included on the same spreadsheet as wind power. There is much less variation in solar power (Figs. 4.13-4.16) than wind power. It is easy to note if solar values do not following the seasonal trend. As an example of the solar power increasing from east to west, the peak value at Bluegrove is around 275 W/m2 compared to 310 W/m2 at Denver City. A direct comparison can not be made between sites with much different latitudes because of the cosine factor. Also a procedure for converting the horizontal and vertical data to predict direct normal insolation needs to be done.

 
Figure 4.13. Solar insolation for Mid Plains, horizontal.
Figure 4.14. Solar insolation for Mid Plains, horizontal.
Figure 4.15. Solar insolation for Rio Grande Valley, horizontal.
 
Figure 4.16. Solar insolation for Bluegrove, vertical.

 

 

Table 4.3. Average Solar Insolation Of Monthly Data.  
Name
Site #
Start
Last
Horizontal
Vertical
Month
Month
W/m2
W/m2
High Plains
Amarillo
6
9/94
1/00
210
156
Dalhart
13
5/96
1/00
212
184
Quay Co, NM
15
2/96
1/00
240
White Deer
14
3/96
1/00
220
160
Mid Plains
Blue Grove
10
2/95
12/99
194
155
Denver City
16
2/96
1/00
240
170
Maryneal
12
1/95
1/00
202
163
Trans Pecos
Hueco Mts
7
11/94
8/97
241
178
Guadalupe Pass*
8
1/95
1/00
214
178
Coastal
Alice
20
8/95
9/97
220
126
La Paloma
21
8/95
8/97
188
Matagorda
9
1/95
12/99
194
126
Raymondville
22
7/95
12/99
195
128
Rio Grande Valley
Carta Valley
24
8/95
12/99
211
148
Mirando City
11
1/95
12/99
214
135
Rio Grande City
23
8/95
12/99
212
132
  * Guadalupe Pass horizontal data is low and has not been corrected. Average solar insolation by month indicates that the seasonal values are essentially the same over the region. The High Plains and Mid Plains both show the increase of solar power from east to west (Figs 4.17-18). Notice that the horizontal values for Guadalupe Pass are constant starting in May (Fig. 4.19). The values are low during the summer as the sensors were mounted on the east side of the tower and there is tower shadow in the afternoon. The values for the Coastal (Fig. 4.20) and Rio Grande Valley (Fig. 4.21) are also very similar, except for the dip in May for the Rio Grande Valley.