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Offshore Wind Resources in the Southeast

Bill Bulpitt, Susan Stewart, & Mary HuntGeorgia Tech Strategic Energy Initiative

The Southeast & Mid-Atlantic Regional Wind SummitSeptember 19-20, 2005

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Introduction

• Feasibility study carried out on offshore wind energy potential in coastal Georgia – Funded by NSF PFI grant: InfinitEnergy, A

Coastal Georgia Partnership for Innovation

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Current Study

• South Atlantic Bight– 6 years of highly creditable wind data– 50 m above ocean surface

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SE Continental Shelf

• 80 miles wide

• < 50 m deep

• Conventional foundation technology – <20-30 m

• Plenty of shallow water over horizon

Navy/Skidaway Instrumentation Platforms

Wind Data Details

• 40 miles offshore • 50m above ocean

surface• 27m water depth• 6 Minute Interval

Data from 6/1999- present– Wind Speed @ 50m

• Min, Max & Deviation

– Wind Direction @ 50m

• Deviation

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Annual Wind Speed Distribution (Year 2000)

0

5

10

15

20

25

1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31

Wind Speed (m/s)

% T

ime

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Wind Power Classifications

Wind Power Class

Wind Power

Density (W/m2)1 0 to 2002 200 to 3003 300 to 4004 400 to 5005 500 to 6006 600 to 8007 800 to 2000

P/A=1/2V3

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6 Year Data Averages

Month

Avg. Wind Speed

Avg. Power Density

Approx. Class Month

Avg. Wind Speed

Avg. Power Density

Approx. Class

  (m/s) (W/m2)   (m/s) (W/m2)  

1 8.26 626.7 6 7 6.04 259.8 2

2 8.09 559.8 5 8 6.07 322.0 3

3 8.13 585.0 5 9 8.43 632.4 6

4 7.38 397.3 3-4 10 6.96 397.9 3-4

5 6.76 324.9 3 11 7.28 516.4 5

6 6.29 463.1 4 12 7.96 571.0 5

6 year Avg. 7.36 m/s 479.3 W/m2 Class 4

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Monthly Average Wind Speed Over 6 Year Period

5

6

7

8

9

1 2 3 4 5 6 7 8 9 10 11 12

Month

6 Y

ear

Mo

nth

ly A

vera

ge

Win

d S

pee

d (

m/s

)

Class 7

Class 6

Class 5

Class 4

Class 3

Class 2

Class 1

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Monthly Average Wind Power Density Over 6 Year Period

0

100

200

300

400

500

600

700

800

900

1000

1 2 3 4 5 6 7 8 9 10 11 12

Month

6 Y

ear

Mo

nth

ly A

vera

ge

Win

d P

ow

er (

W/m

^2)

Class 7

Class 6

Class 5

Class 4

Class 3

Class 2

Class 1

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6 Year Averaged Power Density and Frequency

6 Year Average Wind Direction

0

1

2

3

4

5

6

7 Power Density

Frequency

as a Function of Radial Direction(axis indicates % of time (for frequency) and % of total power (for power density))

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Sample Wind Turbine Specifications

• 3.6 MW – Hub height: ~70m-100m– Rotor Diam.: 104m– Swept Area: 8495m2

– 3.5-27 m/s– Nominal wind speed:

14m/s

• 2.0 MW– Hub height: 80m– Rotor Diam: 90m– Swept Area: 6362 m2

– 3.5-25 m/s– Nominal wind speed:

11.5 m/s

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Changes in Hub Height

• Logarithmic Law for adjustment to hub height, z:

– roughness length, l = 0.0002 m (open water)

50

ln

50ln

Z

zl

V V

l

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Wind Power Curves

0

400

800

1200

1600

2000

2400

2800

3200

3600

4000

0 5 10 15 20 25 30

m/s

kW

3.6 MW

2.0 MW

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Average kWh/yearMonth Avg Wind Speed

@ 50m (m/s)A 3.6 MW (kWh)

@ 80mB 2.0 MW (kWh)

@ 80m

1 8.26 1,025,878 703,007

2 8.09 898,333 671,284

3 8.13 955,704 680,881

4 7.38 745,189 570,739

5 6.76 627,457 480,102

6 6.29 491,300 398,100

7 6.04 497,048 413,725

8 6.07 495,854 382,501

9 8.43 890514 737,301

10 6.96 638,718 455,669

11 7.28 800,757 554,307

12 7.96 942,619 653,202

Annual 7.36 9,009370 6,700,817

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Capacity Factors

• Turbine A (3.6 MW)– 28.6%

• Turbine B (2.0 MW)– 38.2%

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Estimated Cost of Energy20 Year Amortization

0.0

2.0

4.0

6.0

8.0

10.0

12.0

4.0% 6.0% 8.0% 10.0% 12.0% 14.0% 16.0%

Financial Discount Rate (%)

Ce

nts

/kW

h

Cost includes 1.8 cents/kWh O&M and Production Tax Credit

2.0 MW Wind Turbine

Conventional Technology Fuel Costs

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Conclusion

• Study concludes that offshore wind energy in the Southeast warrants further study– Resource more significant than early reports– Could generate economically competitive

electricity

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U.S. Offshore Wind Power Jurisdictional, Regulatory &

Permitting Issues

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Jurisdictional Issues

• Local Waters (impact on coastal lands and/or waterways)

• State Waters - coastline to three miles

• Federal Waters - three miles to 12 miles

• Exclusive Economic Zone – to 200 miles

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(cont.) Jurisdictional Issues• No existing wind power generation facilities exist in

U.S. coastal waters• Jurisdictional authority was recently granted to the

Minerals Management Services (MMS) to oversee/regulate national policy for offshore wind developments

• The USACE will remain the agency responsible for permitting offshore wind structures in U.S. coastal waters (based on Section 10 of the Rivers and Harbors Act)

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Regulatory Issues

• Key Factors Determining the Full Range of Applicable Regulatory Requirements – Project size and location– Landfall grid connection location– Jurisdictional boundaries of the ocean (state/federal)– Competing ocean uses around the project footprint– Protected, historic or sensitive areas - both in the ocean

and on coastal lands

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Permitting and Policy Issues• Primary objective of permit is public

involvement– Section 10 of the RHA provides for permit

authority – Permit Application Initiates

• Public hearings • NEPA review – may trigger either

– Environmental Assessment (EA) which may result in a FONSI or Finding of No Significant Impact

– Environmental Impact Statement (EIS)

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Tybee Island Substation

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Comments on Tybee Island

•Geographic Characteristics–Commercial and residential area–School nearby

•Substation Characteristics–Needs to be upgraded–Large footprint

•Landfall Options–Distance to ocean: 500 yards (go through residential and commercial area and sand dune restoration area to get to ocean)

Viewshed – Robert Moses Park

~ 0.5 nautical miles from shore

~ 7.0 nautical miles from shore

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Horns Rev

Country: DenmarkLocation: West CoastTotal Capacity: 160 MWNumber of Turbines: 80Distance to Shore: 14-20 kmDepth: 6-12 mCapital Costs: 270 million EuroStatus: Operational Construction Date: 2002 Manufacturer: VestasTotal Capacity: 2 MWTurbine-type: V80 - 80m diameter / 70m hubheightMean Windspeed: 9.7 m/sAnnual Energy output: 600 GWhWindfarm Developer: Elsam http://www.hornsrev.dk/Engelsk/default_ie.htm

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Scroby Sands

Country: United KingdomLocation: East Anglian Coast, 3km east of Great YarmouthTotal Capacity: 60 MWNumber of Turbines: 30Distance to Shore: 2.5 kmDepth: 4-8 mCapital Costs: about 110 million EuroStatus: BuiltConstruction Date: 2003Manufacturer: VestasTotal Capacity: 2 MWTurbine-type: V80 - 80m diameter/ 60m hubheightMean Windspeed: 7.5 m/s Annual Energy output: Windfarm Developer: E.ON UK

Arklow Bank Site Details

• 60 km south of Dublin

• 7 - 12 km from coast

• 24 km long 2.5 km wide

Arklow

Arklow Project Statistics• Turbines 3.6MW x 7• Dept of piles 35-45m• Weight of piles 280tonne (5m diameter)• Weight of turbines 290tonne• Blades 50.5m, 15tonne each• Nacelle/Hub height 73.5M• Rotational speed 8.5 – 15 rpm• Distance offshore 10km• Onshore cable 5km• Voltage 38kV distribution connected• Rotor diameter 104m > soccer pitch area• 25MW serves 16,000 households (Irish)

• Sandbank 24 miles long & 2.5 wide, depths 3 -20 m• Largest commercially operating turbines installed to date• Largest consented offshore site todate

Source: McAdam