Environmental Engineering Reference
In-Depth Information
Economic and institutional issues also affect micrositing. A good example of all phases of a proj-
ect is the Waubra wind farm (192 MW) in Australia [33], as the website has a description and photos
from community relations, environmental to construction. A detailed site layout map is also shown.
9.8 OCEAN WINDS
Ocean wind observations (see
Section 4.4
) provide a complementary source of information for sit-
ing of offshore wind farms. The advantages of ocean wind maps are:
r
Some satellite wind maps are public domain.
r
All offer global coverage, which means really large areas without a large number of
met towers.
All are accessible in archives spanning several years.
r
r
Accuracy is sufficient for wind resource screening.
r
Ocean wind maps quantify spatial variations.
r
Ocean wind maps are available in resolutions of 400 m, 1.6 m, and 0.25°.
r
Software has been developed for their use.
The major problems with ocean winds are:
r
Data are for 10 m height and values of wind shear are not known.
r
Standard deviations are around 1.2-1.5 m/s on mean wind speed.
r
Data are not available or not as reliable within 25 km of shore.
Ocean winds were used for wind resource estimation for Denmark [34]. Weibull parameters
were calculated from the wind speed data to obtain a wind speed distribution, from which the wind
energy production can be estimated.
The average wind speed for Padre Island, a barrier island off Corpus Christi, Texas, is 5.1 m/s at
10 m height, which is the same value for the ocean winds 25 km from the coast. Data from 10 to 40 m
height indicated an annual average shear exponent of 0.19. A shear exponent of 0.15 was noted for
a site 15 km off Cape Cod, Massachusetts [35]. Also, ocean winds, terrain, and predominant wind
direction will indicate regions of wind potential for islands and near the shore. For example, ocean
winds indicate an excellent wind resource for the islands of Aruba, Bonaire, and Curaçao off the
northern coast of Venezuela.
9.9 SUMMARY
GIS provide a very flexible and powerful tool for terrain analysis relevant to wind energy prospect-
ing. It can be used to reclassify the existing wind maps and to identify areas for meteorological
measurements for possible wind farm sites. In addition, it can be used to quantify the wind power
potential and, in conjunction with numerical models, to quantify the annual energy production.
Once a location is selected, then GIS and topomaps can be used in micrositing. The wind tur-
bines should be located within the wind plant to maximize annual energy production. However, the
90 m resolution may not be detailed enough for micrositing in complex terrain. PNL used a tech-
nique of spline interpolation to fill in a finer grid from the 90 m data. Of course, if the DEM data at
10 m resolution are available, then the interpolation technique is not needed.
A number of numerical models for micrositing are available, and most run on a PC. More power-
ful programs for weather prediction and micrositing, which run on large computers or clusters of PCs,
are also available. In general, these are commercial or the software package has to be purchased.
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