This document discusses wind energy as a renewable resource for electricity and hydrogen production. It provides advantages of wind energy such as producing no greenhouse gas or other emissions. It also discusses constraints including variability in wind speed. The document then covers topics such as the wind power equation, different sizes of wind turbines and their applications, wind resources in India including Tamil Nadu, and operating characteristics and costs of wind turbines. Misunderstandings about wind power are also addressed.

1. Wind Energy
Resource, Advantages, and
Constraints
Ashutosh Singh
B.Tech 4th Year HIT

2. Renewable Resources
and Technologically Viable End-uses
Wind - electricity and No Greenhouse Gas Emissions
hydrogen production
Insurance Against
Conventional Fossil-
based Price Risk No Sulfur Dioxide (SO2),
Nitrous Oxide (NOx), or
Mercury Emissions

3. WIND POWER - What is it?
• All renewable energy (except tidal and geothermal power),
ultimately comes from the sun
• The earth receives 1.74 x 1017 watts of power (per hour) from the
sun
• About one or 2 percent of this energy is converted to wind
energy (which is about 50-100 times more than the energy
converted to biomass by all plants on earth
• Differential heating of the earth’s surface
and atmosphere induces vertical and horizontal
air currents that are affected by the earth’s
rotation and contours of the land  WIND.
~ e.g.: Land Sea Breeze Cycle TURBINES

4. Why Wind Energy?
Wind, for now, is the renewable energy resource/technology of
choice
“Free” resource
A “clean” resource due to:
 Replacement of a “dirty” energy source (coal) and,
 No emissions associated with its use
Can be utilized on underutilized land or on lands currently in
commodity crop production (“harvest” on the surface and “harvest”
above the surface)
Will primarily be used for electricity generation for
immediate end-use or as a “driver” for hydrogen
production

5. Energy Production and the Environment
Energy use in power plants accounts for:
 67% of air emissions of SO2, the primary cause of
acid rain. SO2 causes acidification of lakes and
damages forests and other habitats.
 25% of NOx, which causes smog and respiratory
ailments.
 33% of Hg (mercury), a persistent, bio-accumulative
toxin which increases in concentration as it moves up
the food chain, e.g. from fish to birds, causing serious
deformities and nerve disorders.
SOURCES: Union of Concerned Scientists (UCS)

6. Wind Energy
Benefits
No air emissions
No fuel to mine, transport,
or store
No cooling water
No water pollution
No wastes

7. Wind Resources India
 The Wind Resource Assessment in
India estimates the total wind potential to be
around 45 000 MW (mega watt).
 This potential is distributed mainly in
the states of Tamil Nadu, Andhra Pradesh,
Karnataka, Gujarat, Maharashtra, and
Rajasthan.

8. Wind Power Capacity in India

9. Tamilnadu Wind Potential
Tamilnadu is one of the three
best wind states in the country
The wind installed capacity of the
state is 6548MW as on
31.10.2011. This is 47% of the
country’s total wind installed
capacity.
Most of that potential probably won’t
be developed . . .

10. Wind Energy Basics
Physical & Engineering
Aspects

11. Wind Power Equation
P = ½ * air density * Area Swept by Rotor * Wind Speed 3
P = ½ * ρ * A * V3
1) Power in the wind is correlated 1:1 with area and is extremely sensitive to wind
speed (the cubic amplifies the power significantly)
2) If the wind speed is twice as high, it contains 2 3 = 2 x 2 x 2 = 8 times as much
energy
3) A site with 16 mph average wind speed will generate nearly 50% more electricity and
be more cost effective than one with 14 mph average wind speed (16*16*16) /
(14*14*14) = 1.4927
4) Therefore, it “pay$” to hunt for good wind sites with better wind speeds

12. Energy from the Wind
 Turbine output drives wind economics and output is a strong function of wind
speed
 Wind speed increases with height above the ground
 Power = 1/2 × (air density) × (area) × (wind speed) ³
 Energy in the wind increases as height increases (theoretically)
V2/V1 = (H2/H1)1/7

13. Wind Turbines

14. Turbines: Different Sizes and Applications
Small (≤10 kW)
• Homes (Grid-connected) Intermediate
• Farms
• Remote Applications (10-500 kW)
• Village Power
(e.g. battery changing, water
pumping, telecom sites) • Hybrid Systems
• Distributed Power
Large (500 kW – 5 MW)
• Central Station Wind Farms
• Distributed Power
• Offshore Wind

15. Large Wind Systems
 Range in size from 100
kW to 5 MW
 Provide wholesale bulk
power
 Require 13-mph average
wind sites

16. Typical Turbine Size
1.3 to 1.8 MW rated capacity
Rotor diameter 60 to 80 meters
Tower height 60 to 80 meters
Turbine footprint 10 m x 10 m
245-330 ft. TIP
165-220 ft TOWER
Lowest ground clearance is at
least 100 ft.
Apx. 100 ft.

17. Next Generation Wind
Turbines

19. Wind Turbine Schematic

20. Nacelle for 1.65-MW turbine

21. Cross section of blade for 1.65-MW turbine

22. Variability
Quantifying Wind Power Performance
99% Availability
>90% Operating Time*
30 – 40% Capacity Factor
* Lake Benton, Minnesota Analysis of Windfarm
Operation

23. Expected Output/Capacity Factor
 The capacity factor is simply the wind turbine's
actual energy output for the year divided by the
energy output if the machine operated at its
rated power output for the entire year
 A reasonable capacity factor would be 0.25 to
0.30. A very good capacity factor would be 0.40
 Capacity factor is very sensitive to the
average wind speed

24. Power Curves
The turbine would produce about 20% of its rated power at
an average wind speed of 15 miles per hour (or 20
kilowatts if the turbine was rated at 100 kilowatts).

25. Operating Characteristics of
Wind Turbines
0.66 MW 1.5 MW 1.8 MW 2.5 MW 3.0 MW
Vestas GE Vestas GE Vestas
Hub Height (m) 55 80-85 67-70 80 80-90
Rotor Diameter (m) 47 70.5 80 88 90
Swept Area by Rotor (m2) 1,735 3,904 5,027 6,082 6,362
Cut-in Speed (m/s) 4 3 4 3 4
Cut-out Speed (m/s) 25 25 25 25 25
Rated Speed (m/s) 15 12 16 12 15

26. “Value” of Wind Energy
 The value of a wind turbine or wind farm
depends upon many factors
location
terrain
wind speed = f(location, terrain)
cost of competing energy source
rate structure of competing energy source

27. Wind Insures Against
Fuel Price Risk
 It is estimated that  Value of domestic fuel
generating electricity from source (wind) would have
renewable sources can a direct benefit on the
ultimately save community.
consumers more than
Rs.300/MWh .  Wind energy “Fuel” is
inflation-proof; therefore
impervious to fuel price
hikes

28. Wind - Natural Gas Comparison
Wind Natural Gas
Low Operating Cost High Operating Costs
High Capital Cost Low Capital Cost
Non-dispatchable Dispatchable
No Fuel Supply/Cost Fuel Supply/Cost Risk
Risk
Smog, Greenhouse
No Emissions Gas Emissions

29. Wind Power Costs
Wind Speed
Assuming the same
size project (total MW
installed), the better
the wind resource,
the lower the cost
capture more energy
for the same
maintenance cost.

30. Wind Power Costs
Project Size
Assuming the same
wind speed, a larger
wind farm is more
economical;
economy-of-scale
associated with wind
farm installation

31. Wind Power Isn’t Perfect
 Wind Power output varies over time; it isn’t dispatchable
 Wind Power is location-dependent (rural vs. urban where
it is needed most)
 Wind Power is transmission-dependent for tie-in to the
grid
 Wind Power has environmental impacts (pro / con)
 Wind Power can only meet part of the electrical load

32. Common Misunderstandings
Wind turbines are
only generating
electricity about
one third of the
time.
Wind turbines generate
electricity essentially all
the time, but only at their
rated capacity about 30-
40% of the time

33. References
• www.awea.org
• www.wwea.org
• www.windpower.org