THE CLIMATE ADJUSTMENT PROCESS - Wind Resource Assessment: A Practical Guide to Developing a Wind Project - page 153

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Monitoring mast
Reference site

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Jan-98 Jan-99 Jan-00 Jan-01 Jan-02 Jan-03 Jan-04 Jan-05 Jan-06 Jan-07 Jan-0

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Figure 12-1. Observed wind speeds from a monitoring mast and reference station. Source:
AWS Truepower.

them is established. Then, the much longer historical record from the reference is
applied to this relationship to predict the long-term mean wind resource at the target
site. An example of the relationship between the periods of record for a reference site
and a monitoring mast is provided in Figure 12-1.
That is how the process is supposed to unfold, and often it does so successfully.
However, complications sometimes arise, and the accuracy of the resulting long-term
wind resource estimates depends on how they are handled.
This chapter addresses (i) the assumptions underlying MCP; (ii) the requirements
that must be met for successful MCP; (iii) the data sources most widely used for
MCP, including their advantages and pitfalls; and (iv) various methods of relating
winds observed at the target and reference and of predicting the long-term wind
resource.

12.1 IS THE WIND CLIMATE STABLE?

The key assumption underlying all MCP methods is that the wind resource in the
future will be similar to what it has been in the past; in other words, the wind climate
is stable. In this age of climate change, it is reasonable to ask whether this assumption
holds true and what its implications might be for the accuracy of energy production
forecasts. Even in the absence of climate change linked to greenhouse gas emissions,
the possibility of other sources of change in a site's wind climate, including cyclical