Estimating the Optimal Location of a New Wind Farm based on Geospatial Information System Data

Estimating the Optimal Location of a New Wind Farm based on Geospatial Information System Data

Dec.6 2007Chungwook Sim

How does a Wind Turbine Works?

Generating the Power

- Inside the wind turbine

(retrieved from http://green.nationalgeographic.com)

- Blades

- Low-speed shaft, Gear box, High-speed shaft

- Generator

- Numerical Weather Prediction model

“meso-scale”, “micro-scale”

- Wind Shear Profile

“atmospheric stability”, “roughness”

- Wind Speed at Hub height

- Annual Power prediction

General Sketch of the Project

- Understand the stability influential factors of a wind shear profile

“Richardson Number”, “Monin-Obukhov Length”

- Use GIS to integrate various layers

“Multi-dimensional tools”,

“Spatial-analyst tools”

Objective of the Project

- Navier-Stokes and Continuity Equation of the atmosphere

Physical Concepts of Boundary-Layer Flow

gt fupuuu 2)(2

- Reynolds-Averaged Equations and the Turbulent Momentum Flux

tgt fUUpUUU

2)(2

- Wind Speed

Tt

t ii tdtuT

tu )(1

)(

)()()( tutUtu iii )()( tutU ii

O

- Mixing Length, Friction velocity, roughness length

Logarithmic Wind Shear Profile

tgt fUUpUUU

2)(2

jiijt uu ,

)()()( zUlzUlzUu z

22, Ul zijt

22, )( Uz zijt

z

u

zU xztz

*, 1

0

* ln)(z

zuzU

- Richardson Number and Monin-Obukhov Length

Thermal Stratification on the Wind Shear Profile

zuHz

uU mz ,, *

*

)()()( zzTz Potential Temperature

),,( *3*

2* zuH

z

cu

gH

Uu

cgH

Rimpz

p

S

A

Richardson Number- Monin-Obukhov Length

gH

cuL p

3*

L

zzuH mm ,, *

*** CORRECTION of the Logarithmic Profile

2)(tan2

2

1ln

2

1ln2 1

2

x

xx

L

zm

L

z

L

zm 5

4/1

161

L

zx

L

z

z

zuzU m

0

* ln)(

a) Choose various locations with different terrain conditions in Texas. >> http://ned.usgs.gov// >> http://www.geographynetwork.com/

b) Investigate and collect data of the topography and other stability conditions that can affect the wind power production.

c) Collect climate data of wind speed from NOAA online. >> http://cdo.ncdc.noaa.gov/CDO/cdo

d) Collect the data of demography or energy consumption to determine the energy demand of each location. >>http://landcover.usgs.gov/classes.php

Data Collection

Data Catalog of National Centers for Enviornmental Prediction (NCEP)

NARR (North American Regional Reanalysis) dataset>> http://nomads.ncdc.noaa.gov:8085/thredds/catalog/narr/

- The operational model: Eta model

- Resolution: 32 km grid

- Data available: 1979 to current

- Directories: 3 hourly climatologies, daily, monthly

Format of the data (NetCDF)

Data Verification- Comparison with TCOON Measurements

0:00 3:00 6:00 9:00 12:00 15:00 18:00 21:00 0:00

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

16m

Time (3 hour average)

Wind Speed(m/s)

0:00 3:00 6:00 9:00 12:00 15:00 18:00 21:00 0:00

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

507m

507c

Time (3 hour average)

Wind Speed(m/s)

0:00 3:00 6:00 9:00 12:00 15:00 18:00 21:00 0:00

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

16m

16c

Time (3 hour average)

Wind Speed(m/s)

0:00 3:00 6:00 9:00 12:00 15:00 18:00 21:00 0:00

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

5.0

Time (3 hour average)

Wind Speed(m/s)

NARR v.s. TCOON Measurements

Spreadsheet of Wind Shear Profile Correction

Spreadsheet of Wind Shear Profile Correction

0 1 2 3 4 51

10

100

Wind Shear Profile Correction (Eagle Point Station 507_Sep.2 ,2007)

0:003:006:009:0012:0015:0018:0021:00

Wind Speed (m/s)

Height (m)Log-scale

Wind Power of US

Conditions at the Great Plain- Richardson Number

Conclusions and Future Work

- GIS is useful in integrating a great number of variables

“Map Algebra” with scripts!

- NARR data catalog is useful in estimating climate related topics

“verification required near surface”

- Annual Power prediction v.s. Demand of Power?

“accuracy in wind speed at hub-height”

Questions?