By Michael Hackleman
s there wind where you live? The
wind’s energy can spin a genera-
tor to make electricity or drive a
shaft to pump water. The ques-
tions are: Is there enough wind
energy available? What’s involved in
setting up the system? How big a
windplant do you need? How tall a
tower will it need?
My first foray into using independ-
ent energy sources began in 1972 and
focused on wind. In the intervening
years, I’ve evaluated the wind energy
potential of hundreds of sites. In any
field of work there are tricks to the
trade that come with time and experi-
ence. In this article I will try to distill
my experiences down into tricks any-
one can use to assess the viability of
adding wind energy to one’s own per-
sonal energy equation.
Tapping the energy in wind is a hit-
and-miss proposition without first
understanding the nature of wind.
Windplant installers or owners will
make critical errors in selection, sit-
ing, and use without this knowledge.
Wind is born from the unequal heat-
ing of the earth’s surface and oceans
by solar energy. Wind is, simply
enough, a moving mass of air. What
air lacks in density it more than
makes up for in speed. Put a windtur-
bine in its flow and the wind will spin
it. In effect, the wind machine is
“gathering” some of the wind’s
energy. It must not take it all.
Observations and calculations predict
that only 60% of the wind’s energy
can be extracted without adversely
affecting performance. So, enough
energy must be left in the wind to
allow it to move on.
To the casual observer, there may
seem to be little pattern to the wind.
However, in years of data measure-
ment and recording at airports and cli-
matological stations, distinct patterns
have emerged in both wind direction
and velocities. Annual, monthly, and
even weekly patterns exist.
Assessing wind energy potential
One of the most interesting patterns
shows that in most areas the windiest
months are in the midst of winter and
the calmest months are in summer.
This one feature makes wind energ