Accurate measurements for the purpose of estimating wind energies are proposed in those regions of the USA where the greatest potentials exists. Preliminary wind characteristic calculations from weather station data are provided for the Southern Great Plains region; wind energies from 153 to 212 kW-hr/(ft squared-per year) for 1970 to 1972 are determined. It is concluded that a wind energy survey based on data compiled from weather service stations is feasible for determining the energy potential of a windpowered integrated energy network

Gilmore, E.

Nelson, V.

English

NASA Technical Reports Server

NEED FOR A REGIONAL WIND SURVEY
Vaughn Nelson
West Texas State University
Canyon, Texas
and
Earl Gilmore
Amarillo College
Amarillo, Texas
The economically favorable utilization of wind power on at least a
modest scale will most likely occur in those regions of the U.S. where
the greatest potential exists and where the intermittent nature of the
wind speeds is small. Golding and others (ref. 1) have emphasized the
need for accurate measurements designed specifically for the purpose of
estimating wind energies, but in the U.S. only a small amount of work
has been done. Thomas (ref. 2) indicated that the Southern Great Plains
is a region over which wind speeds are significantly greater than in al-
most any other part of the nation, a fact that is common knowledge to
residents of the area. The area is large, flat, and accessible (both
financially and physically).
The general wind characteristics as indicated by data from the
National Weather Service are as follows:
(1) The average wind speed is high (table 1) . The 31-year mean
for Amarillo, Texas, is 13.7 mph (anemometer height is 23 ft.), and the
wind speed is greater than 15 mph 35 percent of the time.
(2) The average wind speeds are consistently high throughout the
year with the strongest winds in the spring.
(3) The wind occurs both night and day with a small diurnal varia-
tion. The low and high averages by time of day for any month differ by
approximately 3 mph from the average value during windy months.
(4) The duration of calm periods (zero speeds) is short. For
Amarillo, Texas, from 1968 to 1972 there were only two, 9-hour calm
periods and six, 6-hour calm periods. The lowest daily average for the
5-year period was a speed of M.3 mph, which was on one of the days with
a 9-hour calm period. The wind speed frequency curves (fig. 1 and 2)
show that over 90 percent of the time the wind speed is greater than 5
mph. In fact for 1970-72 (3-hr observations) the wind was 9 mph, or
greater, approximately 80 percent of the time.
(5) High wind speeds are also common (table 2) with gusts of over
33
https://ntrs.nasa.gov/search.jsp?R=19740008651 2020-03-23T10:56:22+00:00Z
80 mph. During the spring of 1973 gusts to 100 mph caused extensive
damage in the area.
Preliminary calculations made from National Weather Service data
(Amarillo, Texas) give an indication of the energy in the wind, 153 to
212 kW-hr/(ft2- yr) for 1970 to 1972 (table 3) . Comparable results were
obtained for other years (fig. 3 and 4, data from the 1950's), and a
somewhat smaller value was obtained for Oklahoma (ref. 3).
There are several limitations that must be recognized in using
weather station data to evaluate the wind power potential. Wind speed
is known to vary with height. Obstructions are sometimes found close
enough to anemometers to affect their readings. And the method of
taking an average reading may indicate too little energy. Relatively
small increments in wind speed values lead to large differences in the
calculated values of the energy. For example, systematic errors of 2
and 4 mph give calculated energy differences of approximately 32 and
69 percent respectively. (See fig. 3 and 4.) Such differences in the
available energy magnitude may well determine whether wind energy cap-
ture is economically feasible.
We are beginning a wind energy survey based on the data compiled
at the 10 National Weather Service Stations within 275 miles of Amarillo
(fig. 5) . The wind -survey will provide data from which the wind energy
potential can be estimated for an integrated network. The type of infor-
mation calculated will be the statistical characteristics of the wind
and the time correlations between the stations. As stated earlier, this
area is large (area of the circle is greater than the combined areas of
New England, New York, and Pennsylvania), essentially flat, and acces-
sible; and it encompasses the high wind region.
We are also planning to collect data at sites in the immediate
vicinity of Amarillo. These data could then be correlated with the data
from the National Weather Service.
REFERENCES
1. Proceedings of the United Nations Conference on New Sources of
Energy, Rome, Aug. 21-31, 1961 vol. 7, Wind Power. United
Nations, 1964.
2. Thomas, Percy H. : Electric Power from the Wind. Federal
Power Commission, Washington, D.C., 1945.
3. Energy Storage..Key to Our Economic Future, Oklahoma State
University, School of Electrical Engineering.
DISCUSSION
Q: When you have a Weather Bureau Station a different height than you
like, how feasible is it by relatively short-term measurements at
different heights to get the effect?
34
A: He wants to know if you have Weather Bureau data at a certain height
then how do you get data for different heights. There have been some
tables put out on the difference in height. Say you took wind speed
measurements at 10 feet. Then, what can you estimate the wind speed
to be at 100 feet. About three different tables have been published,
and they really don't agree. I talked to a friend of mine who is in
meteorology, and he said, for example, between 10 and 100 feet just
add 60 percent. Now, I don't know how accurate that is.
Q: My question was about the measurement. Can you do better by particu-
lar tables?
A: I'm not sure actually. Once you get a correlation between heights,
your Weather Bureau data will give you a good idea of the wind ener-
gy potential in that region.
Q: I have a question and a comment. I believe that in the Western part
of your region there is quite a bit of high ground there, and, with
the speed-up factors on high terrain the British investigations
show, I wondered if you were going to get really much in that area.
The second comment: In the Texas area near Dallas there is a high
TV tower that has been instrumented. You might do some extrapola-
tions from that as it is one of the tallest instrumented towers on
the continent.
A: Yes, I have seen some data from that tower. It is in a region of
low wind down there. There is a range of mountains between us and
Albuquerque, and we don't expect much wind from that region. In
other words, it's only when you get out on the high plain that
you get high wind velocity essentially the year round.
Q: I was wondering whether you people had done any work on instrumenta-
tion that would measure wind energy directly. There has been some
suggestion that the anemometer that measures velocity is not what
you're interested in. What you're really interested in is v^.
A: Some people in England measure wind energy directly.
Q: Is that going to be used?
A-l:We don't know yet. Probably.
A-2:Just to a,dd to your reply, the type of the anemometer that the
French used for the wind service during the 1940's and 1950's was
an integrated type of meter. It gave out kilometers per meter
squared. This has certain characteristics itself. It acts as an
energy machine so it doesn't necessarily have the same characteris-
tics. There is a mass of data for France in kilowatt hours.
TABLE 1
MEAN WIND SPEED FOR AMARILLO, TEXAS (1942-72)
Jan.
Feb.
Mar.
Apr.
May
June
13.2
14.3
14.5
15.4
14.8
14.4
July
Aug.
Sept.
Oct.
Nov. 13.2
Dec.
12.4
11.9
13.1
13.0
13.2
13.2
Average = 13.7 mph = 6.09 m/s = 21.9 km/hr
*
*
*
TABLE 2
SPEED OF FASTEST MILE FOR AMARILLO, TEXAS
(Number of Days
50 mph
1968
1969
1970
1971
1972
1973
mph
50
59
59
54
64
65
km/hr
80
94
94
86
102
104
and i
2
3
2
1
2
3
36
TABLE 3
ENERGY (kW-hr/m2) IN THE WIND*
Month
1
2
3
4
5
6
7
8
9
10
11
12
Totals (kW-hr/m2-Yr)
Mtf-hr/ft2-Yr
1970
107
86
180
186
131
150
73
51
120
156
228
184
1652
153
1971
171
272
310
274
277
217
110
102
163
136
133
125
2290
212
1972
\
179
141
164
240
185
117
129
94
159
137
158
149
1852
172
*Values calculated from 3 hour observations of wind speeds,
anemometer at 23 ft., from National Weather Service, Amarillo, Texas.
37
Average Speed
600
WIND SPEED FREQUENCY .CURVE
at
The Amarillo, Texas National
Weather Service Station.
Data for this graph have been
taken from the Summary of Hourly
Observations, 1951 - 1960 and
smoothed to one mph speed intervals
and to one hour time intervals.
33 feetAnemometer height above ground:
000
16 18 20 22 24 26 28 30 32 34 36 38 40 42
WIND SPEED (miles per hour)
FIGURE 1.
600 Average Speed
500
B!
o, a
8 x
X t.
M Q)
3 a.
100
000
WIND SPEED FREQUENCY CURVE
at
The Lubbock, Texas National
Weather Service Station.
Data for this graph have been
taken from the summary of Hourly
observations, 1956 - 1960 and
smoothed to one mph speed intervals
and to one hour time intervals
68 feetAnemometer height above ground:
2 46 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42
WIND SPEED (miles per hour)
FIGURE 2.
38
35 40 45
WIND SPEED (miles per hour)
FIGURE 3.
w
10 15 20 25 30
WIND SPEED (miles per hour)
FIGURE 4.
35 40 45 50
39
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Need for a regional wind survey

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