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Wind Energy

Assistant Professor Mazen AbualtayefEnvironmental Engineering Department

Islamic University of Gaza, Palestine

Adapted from a presentation by

S. LawrenceLeeds School of Business, Environmental Studies

University of Colorado, Boulder, CO, USA

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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

Project Development

Policy

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 prayer wheels in Tibet

600 to 800 The first practical windmills were in use in Iran

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

2000 ~ The world's first operational offshore large-capacity floating wind turbine,

Hywind, became operational in the North Sea off Norway in late 2009. By late 2011, Japan announced plans to build a multiple-unit floating wind

farm, with six 2-megawatt turbines, off the Fukushima coast of northeast Japan

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Increasingly Significant Power Source

coal

petroleum

natural gas

nuclear

hydro

other renewables

wind

Wind could

generate

6% of

nation’s

electricity

by 2020Wind currently produces less than

1% of the nation’s power.

Source: Energy Information Agency

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9Source: American Wind Energy Association

Manufacturing Market Share

%

10

0

2000

4000

6000

8000

10000

MW

2000 2001 2002 2003 2004 2005

U.S. Wind Energy CapacityUS Wind Energy Capacity

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Wind Energy Projects in AC

The Arab Countries (AC) had installed wind energy:

Egypt: 550 MW

Tunisia: 750 GWh annually

Morocco: 289 MW

Algeria and Lybia too are planning on smaller wind farms

to be implemented in the coming years, such as a 10MW

wind farm in Algeria in 2012 and a 61.75MW wind farm in

Lybia.

Source: http://www.renewablesb2b.com/ahk_egypt/en/portal/index/news/show/592e52e2b91fb7a9

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Zafarana farm, Egypt – 550MW

• Operate with wind speeds

between 7-10 m/s• Total of 710 turbines

• 600-850 KW of electricity

each turbine

• Construction began 2001

• Ended by 2010

• Hub height – 47m

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Wind Atlas for Egypt

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Wind Power Advantages

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Advantages of Wind Power

Environmental

Economic Development

Fuel Diversity & Conservation

Cost Stability

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Environmental Benefits

No air pollution

No greenhouse gasses

Does not pollute water with mercury

No water needed for operations

Wind energy system operations do not generate air or water emissions and do not produce hazardous waste. Nor do they deplete natural resources such as coal, oil, or gas, or cause environmental damage through resource extraction and transportation. Wind's pollution-free electricity can help reduce the environmental damage caused by power generation.

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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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Wind farms can revitalize the economy of rural communities, providing steady income through lease or royalty payments to farmers and other landowners.

Although leasing arrangements can vary widely, a reasonable estimate for income to a landowner from a single utility-scale turbine is about $3,000 a year. For a 250-acre farm, with income from wind at about $55 an acre, the annual income from a wind lease would be $14,000, with no more than 2-3 acres removed from production. Such a sum can significantly increase the net income from farming. Farmers can grow crops or raise cattle next to the towers.

Farmers are not the only ones in rural communities to find that wind power can bring in income. In Spirit Lake, Iowa, the local school is earning savings and income from the electricity generated by a turbine. In the district of Forest City, Iowa, a turbine recently erected as a school project is expected to save $1.6 million in electricity costs over its lifetime.

Additional income is generated from one-time payments to construction contractors and suppliers during installation, and from payments to turbine maintenance personnel on a long-term basis. Wind farms also expand the local tax base, and keep energy dollars in the local community instead of spending them to pay for coal or gas produced elsewhere.

Finally, wind also benefits the economy by reducing "hidden costs" resulting from air pollution and health care. Several studies have estimated that 50,000 Americans die prematurely each year because of air pollution.

•Each MW of wind power development provides 2.5-3 jobs years of employment.•Wind provides 1 skilled operations and management job for every 10 turbines installed.•Wind plants can be a valuable source of property tax income for local governments.

Economic Development Benefits

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Fuel Diversity Benefits

Domestic energy source

Inexhaustible supply ال ينضب

Small, dispersed design

US winds could generate more electricity in 15 years than all of Saudi Arabia’s oil—without being depleted.Wind facilities consist of small generators that cannot be easily be damaged at the same time and are easy to replace. If a wind facility is damaged, there is no secondary risk to the public, such as in the release of radioactivity, explosions, or the breaching of a dam.Wind plants can be built quickly to respond to electricity supply shortages.

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Cost Stability Benefits

Flat-rate pricing

Hedge التحوط against fuel price volatility risk

Wind electricity is inflation-proof واقية من التضخم

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Wind Power Design

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Air density

= ½ × air density × swept rotor area × (wind speed)3

A V3

Area = r2 Instantaneous Speed

(not mean speed)

kg/m3 m2 m/s

Power in the Wind (Watts)

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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

Height

Wind energy increases with height to the 1/7 power

2X the height translates into 10.4% more electricity

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1

2

1

2

h

h

v

v

h

h

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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

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 126 m in diameter Resulting in 182 m 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)

Betz Limit with values of 0.35-0.45

Only 10-30% of the power of the wind is actually converted into usable electricity

Example of Wind Power

Largest wind turbines with a rotor blade diameter of 126 m

Air density = 1.225 kg/m3

Wind speed = 14 m/s

Rotors sweep area = π x r2 = 12,470 m2

Wind Power = 0.5 x 12,470 x 1.225 x (14)3

= 21,000,000 Watts (21MW)

The turbine is rated at 5MW due to Betz Limit

Total wind power = 5MW x 8,760 hours =

= 44GWh/year 27

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This picture shows a

Vestas V-80 2.0MW wind

turbine superimposed on a

Boeing 747 JUMBO JET

How Big is a 2.0 MW Wind Turbine?

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0

500

1000

1500

2000

2500

Po

wer,

KW

Mile per Hour, MPH

5040302010

Wind Turbine Power Curve

Vestas V80 2.0MW Wind Turbine

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2003

1.8 MW

106m2000

850 kW

80m

2006

5 MW

182m

Recent Capacity Enhancements

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1. Hub controller 11. Blade bearing

2. Pitch cylinder 12. Blade

3. Main shaft 13. Rotor lock system

4. Oil cooler 14. Hydraulic unit

5. Gearbox 15. Machine foundation

6. Top Controller 16. Yaw gears

7. Parking Break 17. Generator

8. Service crane 18. Ultra-sonic sensors

9. Transformer 19. Meteorological gauges

10. Blade Hub

10

1617

12

5

12

Nacelle Components

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Turbines Constantly Improving

Larger turbines produce exponentially more power, which reduces unit cost of electricity

Specialized blade design for wind turbines

Power electronics improve turbine operations and maintenance

Computer modeling produces more efficient design

Manufacturing improvements

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Improving Reliability

The ―availability‖ of a wind turbine measures the percentage of the time that a plant is ready to generate (that is, not out of service for maintenance or repairs). Modern wind turbines have an availability of more than 98%

1981 '83 '85 '90 '98

% A

vail

ab

le

Year0

20

40

60

80

100

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Wind Project Siting

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Wind PowerClass

10 m (33 ft) 50 m (164 ft)

Speedm/s

(mph)

Speedm/s

(mph)

10 0

4.4 (9.8) 5.6 (12.5)2

5.1 (11.5) 6.4 (14.3)3

5.6 (12.5) 7.0 (15.7)4

6.0 (13.4) 7.5 (16.8)5

6.4 (14.3) 8.0 (17.9)6

7.0 (15.7) 8.8 (19.7)7

9.4 (21.1) 11.9 (26.6)

Wind speed is for standard sea-level conditions.

Wind Power Classes

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Average wind power

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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 = birds

Noise

Aesthetics

Intermittent source of power مصدرمتقطع

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

في خطر( الصقور والبوم والنسور الذهبية)الطيور الجارحة

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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 are not designed properly

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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

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

It is helpful to look at the cost of the energy produced by a wind turbine over the life of turbine, in order to compare to other technologies, although many people acknowledge that there are costs associated with pollution and the use of conventional fuel that are not incorporated in the cost of energy.

To calculate the cost of energy, one should add the cost of financing the project for a year (debt and equity costs) to the cost of operating the project for a year, and divide that by the amount of electricity produced in the year.

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$0.00

$0.10

$0.20

$0.30

$0.40

1980 1984 1988 1991 1995 2000 2005

38 cents/kWh

Costs Nosedive Wind’s Success

3.5-5.0 cents/kWh

The cost of producing electricity from wind energy has declined more than 80%, from about 38 cents per kilowatt-hour in the early 80s to a current range of 3 to 6 cents per kilowatt-hour (KWh) levelized over a plant's lifetime.

In the not-too-distant future, analysts predict, wind energy costs could fall even lower than most conventional fossil fuel generators, reaching a cost of 2.5 cents per kWh.

This dramatic reduction in the cost of energy from wind plants can be attributed largely to technological improvements and economies of scale achieved by manufacturing more and larger wind turbines.

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Construction Cost Elements

Turbines, FOB

USA

49%

Construction

22%

Towers

(tubular steel)

10%

Interest During

Construction

4%

Interconnect/

Subsation

4%

Land

Transportation

2%Development

Activity

4%

Design &

Engineering

2%

Financing & Legal

Fees

3%

The industry benchmark is $1 million per megawatt of installed capacity

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0%

20%

40%

60%

80%

100%

750 kW 1500 kW 3000 kW

Wind Farm Component Costs

Balance of System

Transportation

Foundations

Tower

Control System

Drive Train Nacelle

Blades and Rotor

Wind Farm Cost Components

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Wind Farm Economics

Capacity factor

Start with 100%

Subtract time when wind speed < 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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Improved Capacity Factor

Performance Improvements due to:

Better siting

Larger turbines/energy capture

Technology Advances

Higher reliability

Capacity factors > 35% at good sites

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Wind Farm Economics

Key parameter

Distance from grid interconnect

≈ $350,000/mile for overhead transmission lines in USA

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Wind Farm Economics

Example

200 MW wind farm

Fixed costs - $1.23M/MW

Class 4 wind site

33% capacity factor

10 miles to grid

6%/15 year financing

100% finance

20 year project life

Determine Cost of Energy - COE

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Wind Farm Economics

Total Capital Costs $246M + (10 x $350K) = $249.5M

Total Annual Energy Production 200 MW x 1000 x 365 x 24 x 0.33 = 578,160,000 kWh

Total Energy Production 578,160,000 x 20 = 11,563,200,000 kWh

Capital Costs/kWh 3.3¢/kWh

Operating Costs/kWh 1.6¢/kWh

Cost of Energy – New Facilities Wind – 4.9¢/kWh

Coal – 3.7¢/kWh

Natural gas – 7.0¢/kWh

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Wind Farm Development

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Wind Farm Development

Key parameters

Wind resource

Zoning/Public Approval/Land Lease

Power purchase agreements

Connectivity to the grid

Financing

Tax incentives

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Wind Farm Development

Wind resource Absolutely vital to determine finances

Wind is the fuel

Requires historical wind data Daily and hourly detail

Install metrological towers Preferably at projected turbine hub height

Multiple towers across proposed site

Multiyear data reduces financial risk Correlate long term offsite data to support short term

onsite data

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Wind Farm Development

Zoning/Public Approval/Land Lease

Obtain local and governmental approvals

Often includes Environmental Impact Studies

Impact to wetlands, birds

Negotiate lease arrangements with ranchers, farmers, etc.

Annual payments per turbine or production based

:ranchersمربي الماشية

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Wind Farm Development

Power Purchase Agreements, PPA Must have upfront financial commitment from utility

15 to 20 year time frames

Utility agrees to purchase wind energy at a set rate

e.g. 4.3¢/kWh

Financial stability/credit rating of utility important aspect of obtaining wind farm financing

PPA only as good as the creditworthiness of the uitility

Utility goes bankrupt – you’re in trouble

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Wind Farm Development

Connectivity to the grid

Obtain approvals to tie to the grid

Obtain from grid operators

Power fluctuations stress the grid

Especially since the grid is operating near max capacity

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Wind Farm Development

Financing

Once all components are settled…

Wind resource

Zoning/Public Approval/Land Lease

Power Purchase Agreements (PPA)

Connectivity to the grid

Turbine procurement

Construction costs

…Take the deal to get financed

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Source: Hogan & Hartson, LLP

Financing Revenue Components

PTC: Project total cost

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Closing the Deal

Small developers utilize a ―partnership flip‖

Put the deal together

Sell it to a large wind owner

Large wind owner assumes ownership and builds the wind farm

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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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Oceanic Energy

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