Environmental Engineering Reference
In-Depth Information
I have seen because they all seem to be incomplete. The
most recent is in a report from the EERE Division of the
US DOE entitled
gov/windandhydro
). It includes one assumption that is
wrong, is missing a discussion of what I call correlations
between wind farms in the same area, and does not
include any estimate of the cost or emissions from the
natural gas generation systems that have to be turned on
to smooth the variations.
The wrong assumption is about the independence of
load variations and wind. In California, for example, we
have the infamous Santa Ana wind: a hot dry high-speed
wind that sometimes blows from the interior toward the
coast. It is the cause of the worst damage from forest
% Wind Energy by
res.
But, also, when it blows demand for air conditioning goes
up and the winds are so high that wind turbines have to
shut down. To be sure, this increase in demand coupled to
a decrease in supply is a rare occurrence, but rare condi-
tions can cause a great deal of damage as we have seen in
the recent economic meltdown and credit squeeze. In his
recent book [
], N. N. Taleb called rare and important
events
“
black swans.
”
There are potential black swans in
the energy area too.
The second issue is the correlation between the outputs
of wind farms in the same region. This may have been
analyzed, but if so I have not found it. Clearly, if the wind
is not blowing in one place, it is not likely to be blowing
only a few miles away. I asked one of the California
experts about this and his answer was that the correlation
length (the distance that you have to go to get very
different conditions) was about
miles. That
would say if the wind is not blowing at one wind turbine,
to
