Wind EnergyResource, Advantages, and
Constraints
Ashutosh SinghAshutosh Singh
B.Tech 4B.Tech 4thth Year HIT Year HIT
Renewable Resourcesand Technologically Viable End-
uses
Wind - electricity and hydrogen production
No Greenhouse Gas Emissions
Insurance Against Conventional Fossil-based Price Risk No Sulfur Dioxide (SO2),
Nitrous Oxide (NOx), or Mercury Emissions
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
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
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)
Wind Energy Benefits
No air emissions
No fuel to mine, transport, or store
No cooling water
No water pollution
No wastes
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.
Wind Power Capacity in India
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 . . .
Wind Energy Basics
Physical & Engineering Aspects
Wind Power EquationP = ½ * air density * Area Swept by Rotor * Wind Speed3
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 23 = 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
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
Wind Turbines
Turbines: Different Sizes and Applications
Small (10 kW)• Homes (Grid-connected)• Farms• Remote Applications
(e.g. battery changing, water pumping, telecom sites)
Intermediate
(10-500 kW)• Village Power• Hybrid Systems• Distributed Power
Large (500 kW – 5 MW)
• Central Station Wind Farms
• Distributed Power• Offshore Wind
Large Wind Systems
Range in size from 100 kW to 5 MW
Provide wholesale bulk power
Require 13-mph average wind sites
Typical Turbine Size1.3 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
Lowest ground clearance is at least 100 ft.
165-
220
ft T
OW
ER
245-
330
ft. T
IP
Ap
x. 1
00 f
t.
Next Generation Wind Turbines
Wind Turbine Schematic
Nacelle for 1.65-MW turbine
Cross section of blade for 1.65-MW turbine
VariabilityQuantifying Wind Power Performance
99% Availability
>90% Operating Time*
30 – 40% Capacity Factor
* Lake Benton, Minnesota Analysis of Windfarm Operation
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
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).
Operating Characteristics of Wind Turbines
0.66 MW 1.5 MW 1.8 MW 2.5 MW 3.0 MWVestas 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
“Value” of Wind Energy
The value of a wind turbine or wind farm depends upon many factors
locationterrainwind speed = f(location, terrain)cost of competing energy sourcerate structure of competing energy source
Wind Insures Against Fuel Price Risk
It is estimated that generating electricity from renewable sources can ultimately save consumers more than Rs.300/MWh .
Value of domestic fuel source (wind) would have a direct benefit on the community.
Wind energy “Fuel” is inflation-proof; therefore impervious to fuel price hikes
Wind - Natural Gas Comparison
WindLow Operating CostHigh Capital CostNon-dispatchableNo Fuel Supply/Cost
RiskNo Emissions
Natural Gas
High Operating Costs
Low Capital Cost
Dispatchable
Fuel Supply/Cost Risk
Smog, Greenhouse Gas Emissions
Wind Power CostsWind 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.
Wind Power CostsProject Size
Assuming the same wind speed, a larger wind farm is more economical; economy-of-scale associated with wind farm installation
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
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
References
• www.awea.org
• www.wwea.org
• www.windpower.org