Blue font and lines – need to know These are all lift-type (the sweep surface faces the wind)

These are suitable for utility-scale generation Too much interference from tower Not high enough above ground

Wind

Drag-Type - not suitable for serious power

4 m/s cut-in 12.5 m/s rated power 25 m/s cut out 56 Pmax region, pitch regulated to hold Pmax cubic 25 1 mile = 1609 m

Desert Sky Wind Farm - Map

•

Dallas - 400 Miles

•

San Antonio - 266 Miles

•

Odessa - 90 Miles

•

Ft. Stockton - 50 miles

•

McCamey - 20 Miles

•

Iraan - 12 Miles

Desert Sky Wind Farm (approx 300 miles due west of Austin)

330 ft 215 ft At least 100 wind turbines in a wind farm Approx. 10 wind turbines (15 MW) per square mile. Thus, a farm needs at least 10 square miles.

Metric units – about 6 MW per square km.

115 ft Operate at 10 – 20 RPM, with wind speed range 8 – 56 MPH

GE 1.5S Wind Turbine Operation

•

Operates in 8-56 mph wind speeds

•

Each turbine is a self-contained independent power plant, no operator intervention required

•

Onboard weather station, yaw control facing wind

•

Variable speed, operates from 10 20 RPM rotor/blade assembly, generator speeds 850 to 1440 RPM

Nacelle Layout

O&M - Non-Routine Corrective Maintenance

• •

Blade repairs, lightning damage & leading edge erosion.

• Blade inspections and repairs are completed annually. • About 25 lightning related repairs per year.

25 lightning-related repairs per year per 100 turbines

• Since commissioning, three blades have required replacement due to lightning damage.

Gearbox failures and subsequent replacement.

• Gearbox life cycle appears to be 5-8 years.

Note: The repairs mentioned above require two cranes, a large 300 ton crane and a smaller 100 ton crane. Crane availability and expense are serious issues facing wind farm owners. Demand for crane service is currently outpacing availability.

x

K

.

E

.

 1 2

mv

2 ,

P



d dt



K

.

E

.

  1 2

v

2

dm dt P

 1 2

v

2 

A dx dt

 1 2 

Av

3

Better performance when cold Ideal gas law, PV = nRT.

P

1

V

1

T

1 

P

2

V

2

T

2

For constant P,

V

2 

V

1

T

2

T

1

so as T ↑, V ↑. As V ↑ , then ρ ↓ . Result is as T ↑ , then ρ ↓.

K T

 273 .

15   15 273 .

15   

K

P

(

z

) 

P

(

z



dz

) 

g



Adz A dP

  

g



dz



P



MW

 10  3

RT

MW = molecular weight R = gas constant T = degrees K

dP dz

 

gP



MW RT

 10  3    1 .

185  10  4 

P P



P o e

 1 .

185  10  4

z

P o = 1 atm, T = 15 ºC, z meters  

o

 

o e

 1 .

185  10  4

z

,  1 .

225

kg

/

m

3

K A

Drops about 0.1 per 1000m, and about 0.1 per 30 º C Relative Air Density ( Nominal 1.0 at Sea Level, 15 Deg C) 1.15

1.10

Sea Level 1.05

1.00

500 m 1000 m 0.95

0.90

0.85

0.80

1500m 2000 m 2500 m 0.75

0.70

-20 -15 -10 3000 m -5 0 5 10 Temp - C 15 20 25 30 35 40

v v o

  

H H o

  

Variation of Wind Speed with Height above Ground

v o , H o : velocity and height at reference position, usually 10 meters above ground.

1 7

th

power law

Betz Limit – Max theoretical turbine energy capture = 59.3% of swept area when downwind is slowed to 1/3 rd of the upwind speed.

swept

Betz Limit – Max theoretical turbine energy capture = 59.3% of swept area when downwind is slowed to 1/3rd of the upwind speed.

TSR



Tip Speed v wind

 

rotor

(

rad

/ sec) 

R rotor

(

m

)

v wind

(

m

/ sec)

Moderate: 6.4 - 7 m/s Good: 7- 7.5 m/s Excellent: >7.5 m/s

GE 1.5MW Turbines