The document provides details on conducting a wind resource assessment program. It discusses the importance of assessing the wind resource to determine a site's viability for wind energy projects. The assessment should measure parameters like wind speed, direction, and temperature at various heights. It outlines best practices for the measurement plan, instrumentation, data collection and quality assurance to obtain reliable wind resource data. The assessment aims to characterize the wind resource to inform wind farm design and maximize energy production.

2. And He it is Who sends the winds as
heralds of glad tidings, going before
His mercy, and We send down pure
water from the sky,

3. Wind Resource Assessment
Program
Prepared by
Eng. Ashour Abdelsalam Moussa
Supervision by
Eng. Usama Said Said
Wind Energy Dep.,
New & Renewable Energy Authority (NREA)

4. SOURCES OF ENERGY
CONVENTIONAL / NON-
RENEWABLE SOURCES
•OIL
•COAL
•WOOD

5. The World’s Energy
Resources Are Limited!

6. Renewable Energy Sources
Solar Tidal
Wind Geo
Bio

7. All renewable energy
(except tidal and
geothermal power),
ultimately comes from
the sun.
About to per cent of
the energy coming from
the sun is converted into
wind energy. That is
about to times
more than the energy
converted into biomass
by all plants on earth.

8. Why Renewable Energy?
• Main Reasons: -
The growth of Energy Demand
Fast depletion of fossil fuel.
Global environmental problems.

9. Is Solar Energy efficient to meet our needs ?
• In one year Earth receives TWY of
Solar Radiation.
• Energy Consumption today = TWY.
The Answer for the previous question: Yes
Solar Energy can meet our needs.

10. Principal Features of Non-Conventional
Energy
Renewability of the sources.
Flexibility of technology
adaption.
Diversity of the Sources.

12. Why assess wind resource
.The Power in the wind is proportional to Cube of
the wind speed ( difference in wind speed
makes about change in wind power). This
is the primary reason for wind resource
assessment.
. Wind speed, wind shear*, turbulence** and gust
intensity all need to be specified when procuring a
wind turbine and designing its foundation….etc.
*Wind shears (large differences in the mean wind speed over the rotor) give
large fluctuating loads and consequently fatigue on the wind turbine blades,
because the blades move through areas of varying wind speed.
**Turbulence causes dynamic loads on wind turbines. The strength of the
turbulence varies from place to place. Over land the turbulence is more intense
than over the sea

13. . Turbine manufacturers concerns max.
turbulence intensity ( ), max. wind shear
acting on blade area ( ) and max. one
second gust used for foundation design
Wind Resources assessments are the
cornerstone of identifying and mitigating risks
and for realizing the potential rewards from a
project.

14. Without wind resource,
no wind project will even be viable.

15. Site Visits and Evaluations
– Visits should be conducted to all suitable
areas with the main goals of verifying site
conditions.
The evaluator should use the following:-
• The site topographical map
• A Global Positioning System (GPS)
• A Camera
• A compass

16. Preliminary Area Identification
based on information such as :
previous wind data,
Topography,
Flagged trees ..etc.
A new wind measurement sites can be selected.

20. Griggs – Putman Wind Index
This index is based on the permanent
tree deformation caused by wind and
is useful for estimating the average
wind speed in an area.

21. Use vegetation to know wind
direction and intensity

22. Prevailing Wind Direction
Important to check direction when
setting up instrument

23. Information in the resource
assessment will include :-
• Daily average wind speeds
• Monthly average wind speeds
• Annual Average wind speeds
• Frequency distribution
• Wind Rose
• Wind power density
• Turbulence intensity

24. Frequency distribution
•The basic tool for estimate
energy production.
•It shows the % of time that the
wind blowing at certain speed.
The wind speed are binned,
meaning that speed between
and m/s are binned as m/s,
wind speeds between and
m/s are binned as m/s, and
so on.

25. Frequency distribution + Power Curve
Energy Production
To assess a site’s wind power production potential, the
wind speed frequency distribution must be multiplied
by a representative wind turbine power curve.

26. Wind rose is a useful
tool to know the
wind blows.
It is a valuable tool
for project layout
and micro-siting

27. Wind Power density (W/m )
• It is defined as the wind power available per unit
area swept by the turbine blades.
• It is a true indication of wind energy potential in
the site than wind speed alone.
• Its value combines wind speed distribution and
air density.

28. Wind Power Class Table
Class Resource Wind Power Wind speed
Potential density m/s
w/m
Poor < <
Marginal – –
Moderate – –
Good – –
Very Good – –
Excellent – –
Outstanding > >

29. Turbulence intensity
• It is the rapid disturbances in the wind speed and
direction.
Low <
Medium ~
Large >
• High turbulence level cause extreme loading on
wind turbine components.
• Turbulent locations will severely limit the lifetime
of Wind turbines and maximum the chance of
their catastrophic failures.
• Standard deviation used for turbulence
Turbulence intensity = standard deviation of wind
speed/ mean wind speed

30. Standard deviation of wind speed calculation (σ)
•A number that indicates how much wind speed changes
above or below the mean
•Example :For set of data v = m/s n = times
v = m/s n = times
v = m/s n = times
Total Number of times occurrence (n) =
mean wind speed = (n xv + n xv + n xv )/n =
( x + x + x )/ = m/s
σ = /(n- ){(n xv ^ + n xv ^ + n xv ^ ) – /n (n xv
+n xv +n xv )^ } = {( x( ) + x( ) + ( ) –
( )( x + x + x ) } = m /s
σ= m/s
Turbulence intensity = standard deviation of wind speed/ mean
wind speed = / =

31. Once this assessment is
completed, an accurate
picture of wind resource at
the site should be clear

32. Site Screening Process
When analyzing a region for potential wind farm
locations, the most practical method is to look first for
locations that are completely constrained from wind
farm development and to remove them from analysis.
Some -step process that addresses wind resource
evaluation, evaluation of land suitability, analysis
of site-specific suitability, preliminary site ranking.

33. Step – Initial Screening of Wind Resource
The most important factor in selecting a wind energy
site is the wind resource itself. Many factors can be
considered in the wind resource assessment process,
including:
• Local meteorological data
• Local “common knowledge”
• Biological and physical indicators.

34. Step – Initial Screening for Land Suitability
All land with a “Good” or better wind energy
resource may not be suitable for wind energy
development Factors that would eliminate a site
from consideration include:
• National parks, wetlands, or other areas
where development is prohibited.
• Migration routes of migratory bird species
• Some military areas
• Culturally
sensitive areas (religious, historic,
or archeological sites)

35. Step – Factors Affecting Site Suitability
There are many factors that affect site suitability.
These factors, which will impact the costs and
performance of a project :-
Transmission Capacity and Accessibility
Site Terrain, Accessibility, and Complexity
Terrain Orientation to Prevailing Wind
On-Site Vegetation
Soil Conditions
Aviation/Telecommunications Conflicts
Site Capacity
Cost of Land

36. Step – Site Ranking Criteria
Note that the maximum possible score for each criterion
is not the same. The differences reflect the relative
importance of the criteria.

38. Micrositing
Micrositing is used to position one or
more wind turbines within a given
land area to maximize the overall
energy output of the wind plant.
One km of the windy land can
host MW of potential installed
capacity.

39. Total power input
P/A= x xV
Usable power
P/A= x xV x
Turbine power
P/A= x xV x x

42. The distances between the turbines
have a strong effect on the energy
output of the wind park.
This effect is described by the park
efficiency the relation between :-
(the output of the park) / (the output
of the same number of stand-alone
turbines)

43. Wind turbines are typically arranged
in rows perpendicular to prevailing
winds.
If the wind is consistently from one
direction then within-row spacing is
less and row-to-row spacing is
greater.
Within rows the spacing can vary
from to times the rotor
diameter.
Row-to-row distances typically vary
from to times the rotor
diameter.
For sites that have energetic winds Typical array losses
from multiple directions, the row-to-
row spacing and within row spacing for a wind farm are
are similar. ~ %.

44. •Avoid area of steep slope
The wind on steep slopes
tends to be turbulent.
The construction costs are
greatly increased.
•On hill tops, set the turbines
back from edge to avoid impacts
of the vertical component of the
wind.

45. The bottle-neck effect between two elevations

48. A ridge perpendicular to prevailing wind
direction create better wind potential
Tall Ridges clear of trees or obstacles in windy parts
ridgelines that are perpendicular to the prevailing
wind direction are preferred to ridgelines that are
parallel to the prevailing wind direction.

49. Highest elevation within a given area
High elevation is good and typically means
increased wind power

51. Variation of wind speed with height
The increase of the wind speed as a function of
altitude is a known effect. Near the ground , the
wind speed is reduced due to friction caused by
obstacles. the relative increase of wind speed differs
from one location to another

52. Wind Speeds can be adjusted to another
height using the power law equation :
v =v (z /z )∝
V = the unknown speed at height Z
v = the known wind speed at the
measurement height z
∝ = the wind shear factor. it changes with
different roughness, often assumed over
flat open terrain but can increase to for
area with forest or taller buildings.

53. Logarithmic Law
This law takes into account the surface
roughness of the surrounding terrain
Z
V ln
Zo
V Z
ln
Zo
Zo (Roughness Lengths)

54. zo
Zo (Roughness Lengths) is the height above ground
level where the wind speed is theoretically Zero

55. Landscape Type Zo (m)
Large Cities with tall building
Cities with tall buildings
Villages, small towns, agricultural land with
many or tall sheltering, forests and very rough.
Agricultural land with many houses and plants,
or metre tall sheltering with a distance of
approx. metres
Agricultural land with some houses and tall
sheltering with a distance of approx. m.
Agricultural land with some houses and tall
sheltering with a distance of approx. m.
Open agricultural area without fences
Completely open terrain with smooth surface
Water surface

57. Roughness Classes
and Roughness Lengths
If Roughness Length <=
Class = + Ln (length)/Ln( )
If Roughness Length >
Class= +Ln(length)/Ln( )

58. Shelter
Shelter is defined as the relative decrease in
wind speed caused by an obstacle in the
terrain. Whether an obstacle provides
shelter at the specific site depends upon:
– the distance from the obstacle to the site (x)
– the height of the obstacle (h)
– the height of the point of interest at the site (H)
– the length of the obstacle (L)
– the porosity of the obstacle (P)

62. Obstacle (a house)
angle to corner : α
distance to corner : R
angle to corner : α
distance to corner : R
height m, depth : m,
porosity :

64. • To avoid turbulence, turbine should be
placed at a distance or more times
the height of obstacle or vegetation up
wind of the project.

65. How to increase the wind
turbine energy production
To increase the energy production of a wind farm of a
specific design, there are two possibilities available:
. Position the wind turbine at a greater height above
ground. This option involves a wind turbine price
increase. It is therefore necessary to study whether
the increased energy production compensates the
extra price.
. Optimise the wind farm design by re-locating
turbines or removing the ones that produce less.

66. Detailed wind resources
at Zafarana
Red Belt Northing [m]

67. WAsP Program
WAsP (Wind Atlas Analysis and Application
Program)

68. What you need is a way to take the
wind climate recorded at the
meteorological station, and use it to
predict the wind climate at the turbine
site. That is what WAsP does.

69. WAsP = OBS + ROU +ORO

71. WAsP tools
• The following tools are available:
. The OWC Wizard
. The WAsP Map Editor
. The WAsP Turbine Editor

72. Measurement Plan
The Plan should specify the
following:-
Measurement parameters
Equipment type, quality and cost
Number and location of met. stations
Sensor measurement heights
Minimum measurement accuracy,
duration and data recovery.
Data sampling and recording intervals
Data Storage format
Data handling and processing
procedures
Quality control measures
Format of data reports

73. Measurement Parameters
Basic Parameters
– Wind Speed
• Wind Speed data are the most important
indicator of a site’s wind energy
resource.
• Many level measurement heights are
encouraged for determining a site’s wind
shear characteristics.
– Wind Direction
• To define the prevailing wind direction
• Optimizing the layout of wind turbines
within a wind farm.
– Temperature
• An important descriptor of a wind farm’s
operating environment.
• Used to calculate air density.

74. Measured Heights
Parameters
Wind Speed (m/s) m, m, m
Wind Direction m
(deg.)
Temperature (ºC) m

75. Optional Parameters
Solar Radiation
• measure solar resource for later
solar energy studies.
• Indicator of atmospheric
stability.
Barometric Pressure
• Used to calculate air density.
Change in Temperature
With Height
• Provide information about
turbulence and used to indicate
atmospheric stability.

76. Measured Heights
Parameters
Solar – m
Radiation
(W/m )
Barometric – m
Pressure
(KPa)
Delta m, m, m
Temperature

77. How the measurement plan is
carried out?
– Good Management
Every one involved should be familiar
with the program’s overall objectives,
measurement plan and schedule.
– Qualified Staff
The project team should include at
least one person with field
measurement experience, data
analysis and computer skills.
– Adequate resources
an investment in quality equipment,
tools and spare parts.

78. Quality Assurance Plan
• no sensor gives a perfect reading
• much good data is lost due to low
batteries or some other minor problems.
Goals of quality Assurance is to :-
– Guarantee the successful collection
of high quality data.
– Minimize the uncertainties

79. OBSERVATION TIMES
• Minimum year
Two or more years will produce more
reliable results
• Useful data:
– At least for of the duration of the
programme
• Omissions:
– Data gaps Less than one week

80. Station Instrumentation
Basic Sensors
Wind Speed
Cup anemometer or propeller
anemometers are the sensor types most
commonly used for measurement. In
practice, the cup type is most commonly
used for resource assessment.
• Cup anemometer
This instrument consists of three cups
centrally connected to a vertical shaft for
rotation. the aerodynamic shape of the cups
converts wind pressure force to rotational
torque. A transducer in the anemometer
converts this rotational movement into an
electrical signal. which is sent through a wire
to a data logger.

82. • Cup Anemometer measures Wind Speed.
• Constructed from Aluminum and Stainless
Steel.
• Measuring range : m/s.
• Linearity (High correlation between the
output of a sensor and the changes in
environment).
• Calibration equation U = Ao + Bo x f. (Ao,
Bo Calibration Coefficients , f Frequency in
Hz).

83. – Propeller anemometers
This instrument consists of a propeller
mounted on a horizontal shaft. The
propeller anemometer also generates
an electrical signal which is sent
through a wire to a data logger.

84. Non Rotational Type
– Pressure Tube
• Use for calibration
– Hotwire
• Non linear, very sensitive
– Laser and acoustic anemometers
• D, Expensive ( Euro)

85. Ultrasonic
popular for marine use
display wind speed and direction

86. SODAR
(Sonic Detection And Ranging)
system is a ground based
remote sensing system for the
measurement of vertical profiles
of the horizontal wind vector
and turbulence.
• Use acoustic signal bounced from ground unit up
into the air and reflected back and captured to
measure wind speed and direction.
• Cost US$
• Excellent for detail studies of winds - m
high

87. Wind Direction
• A wind vane is used to measure wind
direction.
• The vane aligning itself into the wind.
• Most wind vanes use a potentiometer
type transducer that outputs an
electrical signal relative to the
position of the vane. this signal is
transmitted via wire to a data logger.
• The most familiar type uses a fin
connected to a vertical shaft.

88. Wind vane problem arise more from
confusion on orientation

90. Data Loggers
• Data logger (or data recorders) is
connected to the sensors for displaying,
storing and transmitting the data in
engineering units.

91. Installation of Monitoring Stations
The installation phase can
proceed once the site
selection has been
completed and the
necessary equipment
acquired.
The quality of the data
collected depend on the
quality of the
installation.

92. Tower Installation
• Towers can be erected almost anywhere,
but the task is much easier if the terrain
is flat and free of trees.
• The Guy anchors should be located at
each of the four directions (N, E, S, W).
• The tower raise along one of these
directions, near to the prevailing wind
direction as possible.

93. Installation Wind Speed and
Directions Sensors
– Mount the upper level sensors at least cm
above the tower top to minimize tower shading
effects.
– In lattice tower position the sensor at least
tower widths (one face for triangular lower)
– In tubular tower position sensors at least
tower diameter.
– Orient sensors into the prevailing wind
direction.
– Locate sensors above the horizontal mounting
hardware at a height equal to at least eight
diameters of the mounting hardware.

94. Safety
Risks:-
• Falling towers
• Falling from towers
• Falling equipment
The team member should:-
• Be equipped with the proper safety
equipment (hard hats, protective gloves,
safety belts and proper foot attire) .
• have first aid kit.
• Use common sense during the installation
(very high wind speed, lightning activity)
postpone work until the danger has
passed.

95. Data Storage Devices
There are two commonly used format
for recording and storing data :-
– Ring Memory
In this format, data archiving is continuous, However,
once the available memory is filled to capacity, the
newest data record is written over the oldest. the data
must be retrieved before the memory capacity of the
storage is reached.(DSU X, DSU F)
– Fill and Stop Memory
Once the memory is filled to capacity, no additional data
are archived. the device must be replaced or downloaded
and erased before the data logger can archive new
data.(DSU , DSU E).

97. Data Storage Capacity (days)
The storage capacity depend on the averaging interval and the
number of channels.
Int.
min
Number of Channels

98. Data Transfer Equipment
Data are typically retrieved and
transferred to a computer either
manually or remotely:-
A- Manual Data Transfer
This method requires site visits to
transfer data. Typically this involves
two steps:
• Remove and replace the current
storage device or transfer data directly
to a laptop computer.
• Upload the data to a central computer.

100. Data Reading Program
connect the Data Storage Unit (DSU) to a PC using DSU Reader

101. B. Remote Data Transfer
Remote transfer requires a
telecommunication system to link the
data logger to the central computer.
The communications system may :-
– direct wire cabling.
– Satellite modems
– Phone lines
– Cellular phone equipments (more
expensive)

104. Documentation
The following topics should be
included:-
– Site Description
• Location Name
• Elevation/Latitude/Longitude of the site
• The installation date and the
commission time.
• surrounding description
• prevailing wind direction
• Magnetic Declination

105. Site Equipment List
• For all equipment (data logger, sensor
and support hardware).
• Document the following:-
– Model
– Serial Number
– the mounting heights
– directional orientation

107. Data Protection and Storage
There is a risk of data loss during the
measurement program.
– faulty or damaged sensors
– loose wire connections
– temperature extremes
– Low battery
– data logger malfunctions
– Damage hard drives and floppy disks.
– Data can be over-written or erased.
To reduce the risk of data loss
– maintain multi copies of the database, or store
each copy in a separate location not in the same
building.
– Ensure that all personnel (data handling) are fully
trained.
– Data validation

108. Data Validation
The goal of data validation is to
detect errors.
The validation routines can be
grouped into two main categories :-
• General System checks
• measured parameters checks.

109. General System Checks
Two simple tests evaluate the collected data
• Data Records
The number of data must equal the
expected number of measured
parameters.
A year of ten minute data is
records ( x x = ).
• Time Sequence
This test should should focus on the
time and date stamp of each data
record.

110. Measured Parameters Checks
These tests represent the heart of the data
Sample Parameter Validation Criteria
Average Wind Speed: offset < Avg. < m/s
Wind Direction : ° < Avg. ≤ °
Temperature Seasonal Variability: °C < Avg. < °C
Barometric Pressure Average: kPa < Avg. < kPa
One Hour change in wind speed average: < m/s
One Hour change Temperature average: <= º
Three Hour change in Pressure average: < kpa

111. Treatment of
missing data
Parameter Value
Wind Speed
Wind direction
Air Temperature
Temp. gradient
Pressure
Solar radiation

112. Data Recovery
Data Recovery Rate= (Data Records
Collected/Data Records Possible) x
For example:-
The total possible number of -minute
records in January is ( x x ).
If records were deemed invalid.
The data records collected = -
=
Data Recovery Rate =
( )x =

113. Measurement System
Accuracy and Reliability
A- The measurement of wind speed, for example,
requires that several components (sensor,
cabling and data logger), each contributing an
error to the measured parameter.
Accuracy = {(measured value – Accepted
Standard Value) / Accepted Standard
Value} X
for wind speed ≤ %
B- Reliability
System reliability is a system’s ability to provide
valid data for a parameter over its measurement
range. the best indication of a product’s
reliability is its performance history.

114. Quality of wind data
• The wind data must be accurate
– equipment design and specification
– calibration of anemometers
– careful mounting of sensors on mast
– verification of sensor output (QA)
• The wind data must be representative
– data collection > year
– data recovery >
– careful siting of mast
• The wind data must be reliable
– Operation and maintenance

115. Costs and Labor Requirements for a Wind
Resource Assessment Program
Program costs can be divided into three main
categories labor, equipment and expenses
A. Labor Tasks
Administration, Site Selection, Installation,
O&M and Data Collection & Handling.
B. Equipment
Equipment costs can be obtained from
manufactures, other items to include in the
budget are shipping charges, taxes, insurance,
spare parts, tools. The estimated cost for m
tubular tower equipped with levels of
sensors is about

116. C. Related Expenses
• Travel
• Accommodation and meals
• Remote data transfer
• Land lease fees
• Re-calibration of anemometers

117. • The estimated total cost for a single
station operated for two years is
about .
• Travel expenses can be economized
if more than one site is visited.
• The total cost to operate a second
site is estimated to be to
less than the cost for the first site.

118. Staffing Recommendations
The Wind Resource Program should have :-
. Project Manager
Tasks :-
• Ensure that human and material resources are
available.
• Oversee the measurement and quality
assurance plans

119. . Field Manager
Tasks :-
• Installs and maintains the monitoring
equipments.
• Transfer the data to home office.
• Should be available whenever a
problem arises in the site.
. Data Manager
Tasks:-
• Data validation and report generation

120. Please don’t hesitate to contact me for any question
e-mail : ashour_ am@yahoo.com