NABCEP NABCEP Wind Energy Site Assessment

Question 1

What is the primary measurement used to evaluate a site's wind energy potential?

Accepted Answer

Mean annual wind speed at hub height

Answer

Mean annual wind speed at the proposed turbine hub height is the critical parameter because wind power output scales with the cube of wind speed — small speed differences have large energy impacts.

Question 2

Why does wind power output increase with height above ground?

Accepted Answer

Surface friction slows wind near the ground; wind speed increases with height due to the wind shear profile

Answer

Ground surface friction creates a boundary layer that slows wind; wind speed increases with height following the wind shear power law, which is why taller towers capture significantly more energy.

Question 3

What is the Rayleigh distribution used for in wind resource assessment?

Accepted Answer

To statistically model the frequency distribution of wind speeds at a site when only mean wind speed data is available

Answer

The Rayleigh distribution is a probability distribution commonly used to model wind speed frequency when only the average wind speed is known, enabling energy yield estimation.

Question 4

Which federal resource provides publicly available wind resource maps for the contiguous United States?

Accepted Answer

NREL Wind Prospector / Wind Resource Maps

Answer

NREL's Wind Prospector and associated Wind Resource Maps provide publicly accessible modeled wind speed data at various heights across the US to support wind project siting.

Question 5

What does 'wind rose' data tell a site assessor?

Accepted Answer

The frequency and speed distribution of wind from each compass direction at a site

Answer

A wind rose is a graphical tool showing how often wind blows from each direction and at what speeds, helping assessors understand prevailing wind direction and optimize turbine orientation.

NABCEP - North American Board of Certified Energy Practitioners Practice Test

NABCEP - North American Board of Certified Energy Practitioners Practice Test

NABCEP NABCEP Wind Energy Site Assessment