Page 134 - Fluid Power Engineering

CHAPTER7

Wind Resource

Assessment

A few observations and much reasoning lead to error; many
observations and a little reasoning to truth.
—Alexis Carrel

Introduction
Wind resource assessment (WRA) is the discipline of estimating the
strength of wind resources at a planned wind project site. The output
of wind resource assessment, at a generic level, is wind conditions and
annual energy production at a project site. A financial model uses this
datatocomputethefinancialperformanceofthewindproject.WRAis,
therefore, the core activity that determines viability of a wind project.
The chapter starts with an overview of the WRA process. This
chapterwillbedividedintotwoparts.Thefirstwilldealwithprospect-
ing with no onsite measurement data. Before delving into resource
estimation, exposition of sources of wind data is provided, followed
by the most commonly used models. The second part of the chapter
will deal with computations related to spatial extrapolation, long-term
hindcast, and annual energy production.
Chapter 8 will cover advanced topics in WRA, loss estimation,
and uncertainty associated with resource assessment.

Overview of Wind Resource Assessment
Figure 7-1 contains an overview of the WRA process. WRA starts
with a preliminary assessment or prospecting. In this step, alter-
nate sites are evaluated for adequate wind speed based on publicly
available wind resource maps and wind data. The prospecting step

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