U. S. Army Corps of Engineers - Mobile District


     Most big lakes have hydropower generating machinery.  Hydropower was the
very first form of electrical generation.  Early dams converted the force of
falling water into electrical power.  Although no longer the primary source of
energy for our homes, stores, and factories water power still plays an important
part in giving us reliable and inexpensive energy.

      Most hydropower generation is "peaking" power.  The generators are turned
on when there is the most, or "peak", demand for power.  Air-conditioning and
heating are the power uses that often cause the peak demand for power so the
hydropower releases are usually made when temperatures are extreme.

     Hydropower from Corps' lakes is sold to a number of cooperatives and munici-
pal retail suppliers of power.  In order for the power to be sold the Government
must guarantee that certain minimum amounts will be available in dry periods.
These minimum generation targets along with other demands can result in declining
lake levels in droughts.

     Unlike most sources of electricity, hydropower can start quickly. This makes
hydropower an important safety feature of an electric system.  If other power
sources are unexpectedly interrupted, hydropower units can be started in just a
few minutes to take up the slack.

     This is important to remember if you boat or fish in the rivers downstream
of hydropower dams. Although most power releases are scheduled hours or days
ahead, a power system shortage can mean that generation and water release can
start at any time.
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