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The Greening of IT
262 How Companies Can Make a Difference for the Environment

objectives and proximate to fiber optic communications links. In gen-
eral, wind power refers to the conversion of wind energy into a useful
form, such as electricity, using wind turbines. At the end of 2007,
worldwide capacity of wind-powered generators was 94.1 gigawatts.
Although wind produces just a little over 1 percent of worldwide elec-
tricity use, it accounts for approximately 19 percent of electricity pro-
duction in Denmark, 9 percent in Spain and Portugal, and 6 percent in
Germany and the Republic of Ireland (2007 data). Globally, wind power
generation increased more than fivefold between 2000 and 2007.
Because of the energy crunch that reached critical levels during 2008,
wind power is getting a significant push worldwide, and that push
includes television ads and investment by people such as Texas oilman T.
Boone Pickens.
Most wind power is generated in the form of electricity. Large-scale
wind farms are connected to electrical grids. Individual turbines can
provide electricity to isolated locations. In windmills, wind energy is
used directly as mechanical energy for pumping water or grinding grain.
Wind energy is plentiful, renewable, widely distributed, clean, and
ptg
reduces greenhouse gas emissions when it displaces fossil fuel-derived
electricity. Therefore, it is considered by experts to be more environmen-
tally friendly than many other energy sources. The intermittency of
wind seldom creates problems when using wind power to supply a low
proportion of total demand. Where wind is to be used for a moderate
fraction of demand, additional costs for compensation of intermittency
are considered to be modest.
The multibladed wind turbine atop a lattice tower made of wood or
steel was, for many years, a fixture of the landscape throughout rural
America. The modern wind turbine was developed beginning in the
1980s, although designs are still under development.
There is an estimated 72 TW of wind energy on the Earth that poten-
tially can be commercially viable. Not all the energy of the wind flowing
past a given point can be recovered.

Distribution of Wind Speed and Grid Management
The strength of wind varies, and an average value for a given location
does not alone indicate the amount of energy a wind turbine could pro-
duce there. To assess the frequency of wind speeds at a particular loca-
tion, a probability distribution function is often fit to the observed data.