MIT Bates Linear Accelerator Center Wind Energy Resource Assessment

ProjectPreliminary Analysis Report

Presented by: Alex KalmikovWind Energy Projects in Action (WEPA)Massachusetts Institute of Technology

Bates Google Earth visualizationhttp://www.youtube.com/watch?v=cnqsUIGZgHc

December 8 2011

Bates Water Tower Site

• Elevation: 64±1m above mean sea level

• Coordinates +42° 35' 47.90", -70° 58' 42.66" (Latitude 42.596638, Longitude -70.978518)

Bates Water Tower Site

Wind Power Density31

2PWPD UA

NREL table: http://rredc.nrel.gov/wind/pubs/atlas/tables/1-1T.html

Fundamental Equation of Wind Power– Wind Power depends on:

• amount of air (volume) • speed of air (velocity) • mass of air (density)flowing through the area of interest (flux)

– Kinetic Energy (mass, velocity):

• K

– Power is KE per unit time:

• .

– Thus:

• P

AU

dm A Udt

mass flow rate = density·Area·flux

212KE m U

12P 2dm U

dt

• Power ~ cube of velocity• Power ~ air density• Power ~ rotor area ~ square of radius

312P A U

Meteorological Tower • NRG Systems 34m tower

Sensor 1 Sensor 2 Sensor 3 Sensor 4 Serial Number 1021 1022 1016 1023 Monitoring Height 34m 34.2m 20m 20.2m Primary / Redundant 20cm 20cm 20cm 20cm Mounting Orientation Degrees - Magnetic

268 124 268 124

Boom Length 1.5m 1.5m 1.5m 1.5m Mount Above Boom Calibrated by: Otech Otech Otech Otech Calibration Date 10/16/09 10/16/09 10/16/09 10/16/09 Slope (mph/Hz) 0.759 0.758 0.757 0.759 Offset (mph) 0.34 0.38 0.38 0.38 Logger Terminal # Ch 1 Ch 2 Ch 3 Ch 13 Comments:

Sensor 1 Sensor 2 Monitoring Height 33m 19m Mounting Orientation

Degrees - Magnetic 178 178

Boom Length 1.5m 1.5m Mount Above Boom 20cm 20cm Deadband Orientation (º) -2 -2 Logger Terminal # Ch 7 Ch 8 Comments:

Wind Resource Assessment Data collection• 1 year: November 3 2010 - November 7 2011

• Two heights: 20 and 34 meters above the ground

• Data filtering: icing and tower shadow

• Data recovery rate 98.9%.

0 2 4 6 8 10 12 14 160

0.05

0.1

Height 34mWeibullScale=5 WeibullShape=2.32

0 5 10 150

0.05

0.1

Height 20mWeibullScale=3.98 WeibullShape=2.08

Wind Speed [m/s]

Tower Shadow and Data Filtering• Difference between two anemometers mounted at different angles

0 50 100 150 200 250 300 350-4

-3

-2

-1

0

1

2

Wind direction [Degrees]

Win

d sp

eed

diffe

renc

e [m

/s]

Raw dataIce freeze filteredExpected tower shadow

Wind Resource Analysis

Nov.18,2010 Dec.19,2010 Jan.19,2011 Feb.18,2011 Mar.21,2011 Apr.21,2011 May.22,2011 Jun.22,2011 Jul.22,2011 Aug.22,2011 Sep.22,2011 Oct.23,20110

2

4

6

8

10

12

14

16

Win

d S

peed

[m/s

]

10 minute average 34mMonthly average 34mMonthly average 20m

Measured Wind Speed

522.083.983.52922.325.004.431 year

Mean WPD20m

Weibull Shape20m

Weibull Scale20m

Mean Wind20m

Mean WPD34m

Weibull Shape34m

Weibull Scale34m

Mean Wind34m

Wind Resource Analysis Measured Wind Speed

522.083.983.52922.325.004.431 year

482.043.893.44902.375.044.46Oct 2011

242.453.292.92422.764.093.64Sep 2011

441.803.503.10752.024.433.92Aug 2011

262.273.322.93472.764.263.80Jul 2011

312.253.503.10562.574.423.93Jun 2011

552.464.323.83882.625.124.55May 2011

702.024.413.901162.165.344.74Apr 2011

692.354.534.011192.655.594.96Mar 2011

622.494.423.921202.585.564.94Feb 2011

412.113.653.23852.374.844.29Jan 2011

961.934.684.131672.265.975.28Dec 2010

592.204.243.751072.405.324.72Nov 2010

Mean WPD20m

Weibull Shape20m

Weibull Scale20m

Mean Wind20m

Mean WPD34m

Weibull Shape34m

Weibull Scale34m

Mean Wind34m

Wind Shear Estimation

• Shear: increase of horizontal velocity with height

• Power law fit to vertical wind profile

• Wind Shear Exponent

• Matching WPD at 2 measurement heights

-2 -1 0 1 2 3 40

0.005

0.01

0.015

0.02

0.025

0.03

0.035

0.04

0.045

Shear Exponent

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 10

0.005

0.01

0.015

0.02

0.025

0.03

0.035

0.04

0.045

Shear Exponent

DistributionModeMeanMedian

-2 -1 0 1 2 3 40

0.005

0.01

0.015

0.02

0.025

0.03

0.035

0.04

0.045

Shear Exponent0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1

0

0.005

0.01

0.015

0.02

0.025

0.03

0.035

0.04

0.045

Shear Exponent

DistributionModeMeanMedian

00

( ) hU h Uh

Extrapolated Wind Power Density

• Sensitivity to wind shear

• Uncertainty due to vertical extrapolation

91.2691.4891.8191.9992.15Lower bound

364748915292.051.7Upper bound

14513210892.073.4Shear=1/7

27421913692.053.6Shear=0.34

29323013992.052.0Shear=0.36

100m80m50m34m20mElevation

312WPD U

Directional Wind Distribution• Wind rose

34 m

2%

4%

6%

WEST EAST

SOUTH

NORTH

0 - 22 - 44 - 66 - 88 - 1010 - 1212 - 1414 - 1616 - 18

2%

4%

6%

WEST EAST

SOUTH

NORTH

0 - 22 - 44 - 66 - 88 - 1010 - 1212 - 1414 - 1616 - 18

2%

4%

6%

WEST EAST

SOUTH

NORTH

0 - 22 - 44 - 66 - 88 - 1010 - 1212 - 1414 - 1616 - 18

20 m

Directional WPD Distribution• Energy rose

34 m 20 m

2%

4%

6%

WEST EAST

SOUTH

NORTH

0 - 2020 - 5050 - 100100 - 200200 - 300300 - 500>=500

2%

4%

6%

WEST EAST

SOUTH

NORTH

0 - 2020 - 5050 - 100100 - 200200 - 300300 - 500>=500

Turbine Power Estimates

1,800,0001,300,000450,000140,00020,000Approximate Cost [$]

121514.51013Rated Wind Speed[m/s]

2.5 / 254 / 253.5 / 252.5 / 253.5 / 25Cutin / Cutout Speeds[m/s]

502921103.7Rotor Diameter [m]

50503736.620Hub Height [m]

500225100202.4Rated Power [kW]

Polaris America

AeronauticaWindpower

Northern Power Systems

PolarisAmerica

SouthwestWindpowerManufacturer

Polaris 500Aeronautica 29-225Northern Power 100Polaris 20Skystream 3.7

14.469.3611.109.675.24Annual Capacity Factor [%]

634,000184,50097,32016,9601,103Annual Energy Production [kWh]

Shear=1/7

17.9512.3311.7110.265.24Annual Capacity Factor [%]

786,750243,200102,70017,9801,103Annual Energy Production [kWh]

Shear=0.36

Polaris 500

Aeronautica29-225

Northern Power 100

Polaris 20

Skystream3.7

Shear Estimate

Summary• MIT Bates Linear Accelerator Center Wind Energy Resource

Assessment Project

• NRG 34m meteorological tower at Bates Water Tower Site

• 1 year of data: November 3 2010 - November 7 2011

• Wind power class 1 - “Poor” resource potential

• Uncertainty in vertical extrapolation

• Preliminary understanding of prevailing winds

• Selected turbines power estimates

Low wind site may benefit from the newer low wind turbine technology.

Questions