Hydraulic energy is what is produced by the water which
is stored in reservoirs and lakes at a high altitude (so that it
has gravitational potential energy). If at a given moment it falls to a
lower level, this energy is transformed into kinetic energy and
afterwards into electrical energy in the hydroelectric plant.
Advantages: it is a clean energy source, without waste products and is
easy to store. Also the water stored in reservoirs situated at altitude
permits the regulation of the flow of the river.
Disadvantages: the construction of hydroelectric
plants is expensive and needs large networks of power
cables. Reservoirs also mean the loss of productive soil and fauna due
to the flooding of their habitat. They also cause a decrease in
the flow of the rivers and streams below the dam and alter the
quality of the waters. The following animation shows how hydraulic
energy is stored and exploited.