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Wind EnergyWind EnergyNguyen Hoang VietNguyen Hoang Viet

Lab. Nano-Particulate Material ProcessingUniversity of Ulsan

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Ancient Resource Meets 21st Century

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Wind Turbines

Power for a House or City

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Wind Energy Outline History and Context Advantages Design Siting Disadvantages Economics Future

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History and Context

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Wind Energy History 1 A.D.

Hero of Alexandria uses a wind machine to power an organ ~ 400 A.D.

Wind driven Buddhist prayer wheels 1200 to 1850

Golden era of windmills in western Europe – 50,000 9,000 in Holland; 10,000 in England; 18,000 in Germany

1850’s Multiblade turbines for water pumping made and marketed in U.S.

1882 Thomas Edison commissions first commercial electric generating stations

in NYC and London 1900

Competition from alternative energy sources reduces windmill population to fewer than 10,000

1850 – 1930 Heyday of the small multiblade turbines in the US midwast

As many as 6,000,000 units installed 1936+

US Rural Electrification Administration extends the grid to most formerly isolated rural sites

Grid electricity rapidly displaces multiblade turbine uses

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Worldwide Growth in Wind Energy

0

10,000

20,000

30,000

40,000

50,000

60,000

70,000

1997 1998 1999 2000 2001 2002 2003 2004 2005

Rest of the World

India

Denmark

USA

Spain

Germany

MWMW

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This is strange because…

Wind Energy is the Fastest Growing Energy Source in the World!!

Fastest Growing EnergySource in the World

Global Growth by Energy Source, Annual Average,1990-98

25.7

16.8

3 2.1 1.6 1.4 1.2 0.60

5

10

15

20

25

30

Source: REPP,Worldwatch 1998/99

Nuclear

WindSolar PV

GeothermalNat. GasHydroOilCoal

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11Source: American Wind Energy Association

Manufacturing Market Share

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US Wind Energy Capacity

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Installed Wind Turbines

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Colorado Wind Energy Projects

Wind Energy Development Project or Area Owner Date

Online MW Power

Purchaser/User Turbines / Units

1. Ponnequin (EIU) (Phase I)

K/S Ponnequin WindSource & Energy Resources

Jan 1999 5.1 Xcel NEG Micon (7)

1. Ponnequin (Xcel) Project Info

Xcel Feb-June 1999

16.5 Xcel NEG Micon (22)

1. Ponnequin (Phase III)

New Century (Xcel)

2001 9.9 New Century (Xcel)

Vestas (15)

Peetz Table Wind Farm New Century (Xcel) 29.7 New Century

(Xcel) NEG Micon (33)

Colorado Green, Lamar (Prowers County)

Xcel Energy / GE Wind Wind Corp.

Dec 2003 162.0 Xcel GE Wind 1500 (108)

Prowers County (Lamar) Arkansas River Power Authority

2004 1.5 Arkansas River Power Authority

GE Wind 1500 (1)

Prowers County (Lamar) Lamar Utilities Board 2004 4.5 Lamar Utilities Board GE Wind 1500 (3)

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New Projects in Colorado

New Wind Projects in Colorado

Project Utility/Developer Location Status MW Capacity

On Line By/ Turbines

Spring Canyon Xcel Energy / Invenergy Near Peetz Construction to begin in June

60 2005 / GE Wind 1500kW (87)

Wray School District Wray School District RD-2

Wray 1.5 2005 / 1500kW (1)

NA Xcel Energy / Prairie Wind Energy

Near Lamar PPA Signed 69 2005 / 1500kW (46)

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Ponnequin – 30 MW

•Operate with wind speeds between 7-55 mph•Originally part of voluntary wind signup program•Total of 44 turbines•In 2001, 15 turbines added ~1 MW serves ~300 customers ~1 million dollars each•750 KW of electricity each turbine•Construction began Dec ‘98•Date online – total June 1999•Hub height – 181 ft•Blade diameter – 159 ft•Land used for buffalo grazing

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Wind Power Advantages

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Advantages of Wind Power Wind power is a renewable resource, which means using it will not

deplete the earth's supply of fossil fuels. It also is a clean energy source, and produces no carbon dioxide, sulfur dioxide, particulates, or any other type of air pollution, as do conventional fossil fuel power sources.

Because it removes energy directly from the atmosphere, wind power is direct mitigation of global warming.

Economic Development Fuel Diversity & Conservation Cost Stability The energy consumption for production, installation, operation and

decommission of a wind turbine is usually earned back within 3 months of operation.

Different from fossil or nuclear power stations with a huge demand for cooling water, wind turbines do not need water to generate electricity

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Pollution from Electric Power

Source: Northwest Foundation, 12/97

23%

28%

33%

34%

70%

0% 20% 40% 60% 80%

Toxic Heavy Metals

Particulate Matter

Nitrous Oxides

Carbon Dioxide

Sulfur Dioxide

Percentage of U.S. Emissions

Electric power is a primary source of industrial air pollution

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Economic Development Benefits

Expanding Wind Power development brings jobs to rural communities

Increased tax revenue

Purchase of goods & services

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Economic Development Example

Case Study: Lake Benton, MN

$2,000 per 750-kW turbine in revenue to farmers

Up to 150 construction, 28 ongoing O&M jobs

Added $700,000 to local tax base

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Fuel Diversity Benefits Domestic energy source Inexhaustible supply Small, dispersed design

reduces supply risk

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Cost Stability Benefits Flat-rate pricing

hedge against fuel price volatility risk Wind electricity is inflation-proof

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Wind Power Design

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Darrieus Vertical AxisDarrieus Vertical AxisFan Mill Horizontal AxisFan Mill Horizontal Axis

Types of wind machines

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The power in the wind is:The power in the wind is: Power = ½ Power = ½ A VA V33

Using the density of air at sea level:Using the density of air at sea level:Power = 0.6125 AVPower = 0.6125 AV33 (metric) (metric)Power = 0.00508 AVPower = 0.00508 AV33 (mph, ft) (mph, ft)

Power in the Wind (W/m2)

Density = P/(RxT) P - pressure (Pa) R - specific gas constant (287 J/kgK) T - air temperature (K)

= 1/2 x air density x swept rotor area x (wind = 1/2 x air density x swept rotor area x (wind speed)speed)33

A V3

Area = r2

Instantaneous Speed

(not mean speed)kg/m3 m2 m/s

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Wind Energy Natural Characteristics Wind Speed

Wind energy increases with the cube of the wind speed 10% increase in wind speed translates into 30% more

electricity 2X the wind speed translates into 8X the electricity

28V2 = (H2/H1)V1

Wind Energy Natural Characteristics Height

Wind energy increases with height to the 1/7 power 2X the height translates into 10.4% more electricity

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Wind Energy Natural Characteristics Air density

Wind energy increases proportionally with air density Humid climates have greater air density than dry climates Lower elevations have greater air density than higher

elevations Wind energy in Denver about 6% less than at sea level

Blade swept area Wind energy increases proportionally with swept area of the

blades Blades are shaped like airplane wings

10% increase in swept diameter translates into 21% greater swept area

Longest blades up to 413 feet in diameter Resulting in 600 foot total height

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Betz Limit Theoretical maximum energy extraction

from wind = 16/27 = 59.3% Undisturbed wind velocity reduced by 1/3 Albert Betz (1928)

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Rotor Designs

Two blades are cheaper but do not last as long

Three blades are more stable and last longer

• Options include:• Upwind vs downwind• Passive vs active yaw

• Common option chosen is to direct the rotor upwind of the tower with a tail vane

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0

500

1000

1500

2000

2500

KW

MPH

5040302010

Wind Turbine Power Curve

Vestas V80 2 MW Wind TurbineVestas V80 2 MW Wind Turbine

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2003 1.8 MW 350’2000

850 kW 265’

2006 5 MW 600’

Recent Capacity Enhancements

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Rotor Diameter Vs. Output Power Capacity

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1. Hub controller 11. Blade bearing2. Pitch cylinder 12. Blade3. Main shaft 13. Rotor lock system4. Oil cooler 14. Hydraulic unit5. Gearbox 15. Machine foundation6. Top Controller 16. Yaw gears7. Parking Break 17. Generator8. Service crane 18. Ultra-sonic sensors9. Transformer 19. Meteorological gauges10.Blade Hub

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1617

12

5

12

Nacelle ComponentsNacelle Components

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Turbines Constantly Improving Larger turbines Specialized blade design Power electronics Computer modeling

produces more efficient design Manufacturing improvements

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Improving Reliability Drastic improvements since mid-80’s Manufacturers report availability data of

over 95%

1981 '83 '85 '90 '98

% A

vail

able

Year0

20

40

60

80

100

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Photos by George Gull, Cornell University

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Largest ExistingOffshore Turbine is REpower 5M

Beatrice Projectin North Sea will

demonstrate two REpower 5-MW

turbines in offshore

application for the first time. Other firsts for Europe

include:

Deepest water(45 m depth)

Farthest offshore(25 km)

Tower platform and anchoring

concept

750-tonnetruss-work platform

Rotor diameter = 126 m

Suction-caisson anchor

410-tonneturbine and 210-tonne tower

Each rotor bladeweighs 18 tonnes

Sep 2004 installation of turbine rotor in onshore prototype at Brunnsbutel, Germany, in Schleswig-Holstein

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Horns Rev 2-MW TurbinesInstalled Using Self-Propelled A2 SEA Vessels

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North Hoyle 2-MW TurbinesInstalled Using Towed Seacore Jack-Up Rigs

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How Big is a 3.6 MW Wind Turbine?This picture shows a Large Rotor Blades (Shipped by Water Offshore Wind Projects Minimize Transfers) 3.6-MW wind turbine superimposed on a Boeing 74-400

GE 3.6 MW rotor (104 m diameter)

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VCERC submitting a CRADA Proposalto Develop Large-Blade Testing Facility

Opportunities to develop remote

structural monitoring methods for non-

destructive testing of long,composite

aerospace structures

Wind turbine blades require static (bending,

twist) and dynamic (fatigue) load testing to

ensure durability for book life of project. No North

American test facilities now exist that are

capable of testing 70 m long blades.

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Hybridizing Marine Renewables with Offshore Gas for Baseload Power

ADVANTAGES:

•Provides high-value baseload power

•Avoids utility needfor land-based “spinning reserve”to accommodatewind variability

•Submarine power cable to shore more secure, with less environmental impact than gas pipeline

•Avoids onshoresiting challenge of finding cooling water for land-based gas power plants

•Prolongs offshore gas reservoir life for more secure future

Eclipse Energy’s hybrid project in

Irish Sea to come on line in 2007

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Wind Project Siting

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Wind Speed and Power Density Classes

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Siting a Wind Farm Winds

Minimum class 4 desired for utility-scale wind farm (>7 m/s at hub height)

Transmission Distance, voltage excess capacity

Permit approval Land-use compatibility Public acceptance Visual, noise, and bird impacts are biggest concern

Land area Economies of scale in construction Number of landowners

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Wind Disadvantages

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Market Barriers Siting

Avian Noise Aesthetics

Intermittent source of power Transmission constraints Operational characteristics different from

conventional fuel sources Financing

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Wind Energy and the Grid Pros

Small project size Short/flexible development time Dispatchability

Cons Generally remote location Grid connectivity -- lack of transmission capability Intermittent output

Only When the wind blows (night? Day?) Low capacity factor Predicting the wind -- we’re getting better

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Birds - A Serious Obstacle

Birds of Prey (hawks, owls, golden eagles) in jeopardy Altamont Pass – News Update – from Sept 22

shut down all the turbines for at least two months each winter eliminate the 100 most lethal turbines Replace all before permits expire in 13 years

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Wind – Characteristics & Consequences

Remote location and low capacity factor Higher transmission investment per unit output

Small project size and quick development time Planning mismatch with transmission investment

Intermittent output Higher system operating costs if systems and

protocols not designed properly

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Balancing Supply & Demand

Base Load – Coal

Gas/Hydro

Gas

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4000

4500

3000

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Energy Delivery

Lake Benton & Storm Lake PowerFebruary 24, 2002

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Lake Benton II Storm Lake

Combined

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Energy Delivery

Lake Benton & Storm Lake PowerJuly 7, 2003

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Wind Economics

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Wind Farm Design Economics Key Design Parameters

Mean wind speed at hub height Capacity factor

Start with 100% Subtract time when wind speed less than optimum Subtract time due to scheduled maintenance Subtract time due to unscheduled maintenance Subtract production losses

Dirty blades, shut down due to high winds Typically 33% at a Class 4 wind site

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Wind Farm Financing

Financing Terms Interest rate

LIBOR + 150 basis points Loan term

Up to 15 years

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Cost of Energy Components Cost (¢/kWh) =

(Capital Recovery Cost + O&M) / kWh/year Capital Recovery = Debt and Equity Cost O&M Cost = Turbine design, operating

environment kWh/year = Wind Resource

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1979: 40 cents/kWh

• Increased Turbine Size

• R&D Advances

• Manufacturing Improvements

NSP 107 MW Lake Benton wind farm

4 cents/kWh (unsubsidized)

2004: 3 – 4.5 cents/kWh

2000:4 - 6 cents/kWh

Cost of Energy Trend

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Construction Cost Elements

Turbines, FOB USA49%

Construction22%

Towers (tubular steel)

10%

Interest During Construction

4%

Interconnect/Subsation

4%

Land Transportation

2%Development

Activity4%

Design & Engineering

2%

Financing & Legal Fees3%

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Future Trends

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Expectations for Future Growth

20,000 total turbines installed by 2010 6% of electricity supply by 2020

100,000 MW of wind power installed by 2020

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Future Cost Reductions Financing Strategies Manufacturing

Economy of Scale Better Sites and

“Tuning” Turbines for Site Conditions

Technology Improvements

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Future Tech Developments Application Specific Turbines

Offshore Limited land/resource areas Transportation or construction limitations Low wind resource Cold climates

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The Future of Wind - Offshore•1.5 - 6 MW per turbine•60-120 m hub height•5 km from shore, 30 m deep ideal•Gravity foundation, pole, or tripod formation•Shaft can act as artificial reef•Drawbacks- T&D losses (underground cables lead to shore) and visual eye sore

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Wind Energy Storage Pumped hydroelectric

Georgetown facility – Completed 1967 Two reservoirs separated by 1000 vertical feet Pump water uphill at night or when wind energy production exceeds

demand Flow water downhill through hydroelectric turbines during the day or

when wind energy production is less than demand About 70 - 80% round trip efficiency Raises cost of wind energy by 25% Difficult to find, obtain government approval and build new facilities

Compressed Air Energy Storage Using wind power to compress air in underground storage caverns

Salt domes, empty natural gas reservoirs Costly, inefficient

Hydrogen storage Use wind power to electrolyze water into hydrogen Store hydrogen for use later in fuel cells 50% losses in energy from wind to hydrogen and hydrogen to electricity 25% round trip efficiency Raises cost of wind energy by 4X

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U.S. Wind Energy Challenges Best wind sites distant from

population centers major grid connections

Wind variability Can mitigate if forecasting improves

Non-firm power Debate on how much backup generation is required

NIMBY component Cape Wind project met with strong resistance by Cape

Cod residents Limited offshore sites

Sea floor drops off rapidly on east and west coasts North Sea essentially a large lake

Intermittent federal tax incentives

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Many Thanks

for your attention!