Page 195 - Fluid Power Engineering

Advanced W ind Resource Assessment 167

impact on AEP; therefore, sensitivity is one. Table 8-8 illustrates the
computations with generic values; actual values are project-specific
and must be computed as part of a comprehensive assessment.

Nonbankable versus Bankable Resource Estimates
One of the purposes of resource assessment is to quantify the eco-
nomics of a project in a manner that would satisfy an investor. It does
not matter if the project is funded with internal resources or funded
by an external investor. In either case, the assessment must be done
with a rigor that ensures that:

a. High-quality calibrated instruments are used
b. Data has been collected properly
c. Data has been analyzed properly
d. An audit trail exists such that items (b) and (c) can be verified
independently
e. Losses and uncertainties associated with the wind resource
over the long-term are identified and quantified

For purposes of discussion of bankable and nonbankable, assume
that the wind resources are sufficient. As an example, consider an area
in Class 4 wind category with wind speed in the range of 7 to 7.5 m/s at
50-m elevation above the ground. In this area, the difference between
bankable or nonbankable resource estimate is the amount of due dili-
gence that has been performed while performing steps (a)–(e) above
in order to reduce the uncertainty associated with wind resources.
The difference between bankable or nonbankable is not whether the
resource estimate results in good versus poor wind conditions.
Why is uncertainty so important in determining bankability of a
wind project? The reasons are wind energy depends on the cube of
wind speed (in theory, and quadratic, in practice), therefore, small
changes in wind speed estimates can cause the return on investment
of a wind project to fluctuate significantly. A bankable resource esti-
mate is, therefore, one in which enough verifiable data is available to
quantify the uncertainty in wind resource at the planned wind project
location. With uncertainty quantified, an investor can compute returns
on a project for various risk scenarios.
A bankable resource estimate is one that is:

Based on actual onsite measurement data with quality instru-

ments that are calibrated, and not based on anecdotal data
Based on at least 1 year of wind measurement data and not

based on short-term measurement data