1. Advances in Wind Assessment Technology:
Industry Pursuit of Higher Resource
Measurements

2. Presentation Overview
• Wind Resource Assessment (WRA)
o Common systems and practices
o Drivers
o Limitations
o Advances
• Summary

3. WRA – Measurement systems and common
measurement practices
• Lattice or tilt-up tubular
• Existing comm towers
Why measure?
• Reliable data loggers
• Robust, about
Gather dataaccurate wind speed
the sensors with
resource
• Robust = durable
objective to sensor is both
• Ideal reduce
uncertainty and durable
accurate
(manage risk)

4. WRA – Measurement systems and common
measurement practices
• More sensor heights and sensor redundancy
o Maximize wind shear characteristics
o Maximize wind rose coverage
•Variety of sensors
o Pairing of 3-cup anemometers, different brands
o NRG #40C
o P2546A WindSensor
o IEC classification, calibration, cost
o Vertical wind speed sensors more widely used

5. WRA – Measurement systems and common
measurement practices
• Data loggers
o 1-second sampling, 10 minute averaging =
worldwide industry standard
o Increase in data logger sensor capacity
o More sensors require more channels
• More automation
o Data transfer from site automated through
cellular or satellite communication services

6. WRA – Measurement systems and common
measurement practices
TREND
– More sensors and variety of sensors

7. Wind Resource Assessment - LIMITATIONS
• Tower based measurements rarely located precisely
where wind turbines are constructed
• High error in hub height shear extrapolations
• Higher, hub height met towers are expensive structures
requiring concrete foundations
o Cannot be moved once constructed
• Anemometers are fixed or static – only measure a
relatively small, fixed point in time
o Not capable of measuring the complete area utilized by the
wind turbine blades

8. WRA - LIMITATIONS
• Wind turbine maximum blade tip height is not hub height

9. Wind Resource Assessment - DRIVERS
• Larger scale wind farms
• Larger scale wind turbines
o 80m typical though advancing to higher towers some regions
• Higher finance requirements
o We are entering the era of the $1B wind farm
• Lowering of acceptable measurement
$
uncertainty
o Wind turbine manufacturers want to know
more about the resource
–Understand Potential for Significant Destruction
(PSD)
– Protect manufacturer reputation
– Underwriters wind turbine warranty terms
– Correct specification of wind turbine for wind
regime
o Wind farm developers and owners want to know more about the
resource to improve their understanding of project risk

10. WRA - ADVANCES
Remote sensing technologies and the wind industry
o SODAR – SOund Detection And Ranging
o LIDAR – LIght Detection And Ranging

11. WRA - ADVANCES
Remote sensing technologies and the wind industry
• Can be moved around easily
• Are especially effective when used in combination with met
towers (complimentary)
• Can be set up and measuring within minutes
• Measure to maximum blade tip height and beyond (200m+)
• Are also useful AFTER the wind farm is constructed
• Power performance verification
• Operations – grid integration, forecasting
• Wind turbine site suitability studies
• Can be located close to met towers
• LIDAR unaffected by precipitation events (rain, snow)
RS – Essential equipment
for successful wind farm operations?

12. WRA - ADVANCES
Other important incremental advances in tower-based
measurements
• More towers, more sensors
• Increased use of sensor redundancy
• Increased variety of sensors
o Not all sensors measure the same
o Increasing use of vertical wind sensors
• Stricter attention to sensor mounting
• Use of fixed and mobile towers AND remote sensing
o Maximizes understanding of spatial variability without
proportionally increasing cost
o Known as ‘Fixed and Mobile Tower’-methodology (FMT) *
* WindLogics, Haynes, Scott and Moon, Dennis, Understanding Wind Variability in Complex Terrain –
Applying the Fixed and Mobile Tower (FMT) Technique – CanWEA 23rd Annual Conference, 10/2/2007.

13. SUMMARY
EMERGING TRENDS IN WRA
• TOWERS
• More towers are better than less, especially in more
complex terrain
o Met towers are relatively low-cost
– Measure twice – cut once …
– “You can fix a gearbox, you cannot fix the wind”
• Industry using higher met towers with more sensors
o 60m is typical at early measurement stages
• Higher wind turbines and much more attention to
lowering overall measurement uncertainty
• Stricter attention to sensor mounting and documentation
• More sensors and more sensor variety

14. SUMMARY
• Budget constrained projects can utilize FMT
o Technique claims reduced cost without compromising
study outcome
• Using advanced WRA methodologies, such as RS, is in
your best interest
o Supports better financing and warranty terms
o Improves confidence in profitability of the Project

15. About NRG Systems
• Manufacturing
plant located in
Hinesburg, VT USA
• 30+ years – wind
industry experience
• Worldwide logistical
capacity
• ‘Lean’
manufacturing
production
• Sustainable
business values and
commitment
NRG Systems manufacturing plant, Hinesburg, Vermont

16. Thank you
Questions?
David Simkins
Strategic Business Development
NRG Systems, Inc.
davids@nrgsystems.com
802-482-2255
www.nrgsystems.com