118 Electrical Power Systems Technology
POTENTIAL POWER SOURCES
olar power S is one potential electrical power source. The largest energy
source available today is the sun, which supplies practically limitless en-
ergy. The energy available from the sun far exceeds any foreseeable future
need. Solar cells are now being used to convert light energy into small quan-
tities of electrical energy. Possible solar-energy systems might include home
heating or power production systems, orbiting space systems, and steam-
driven electrical power systems. Each of these systems utilizes solar collec-
tors that concentrate the light of the sun so that a large quantity of heat will
be produced. Potentially, this heat could be used to drive a steam turbine in
order to generate additional electrical energy.
Geothermal systems also have promise as future energy sources. These
systems utilize the heat of molten masses of material in the interior of the
earth. Thus, heat from the earth is a potential source of energy for power
generation in many parts of the world. The principle of geothermal systems
is similar to other steam turbine-driven systems. However, in this case, the
source of steam is the heat obtained from within the earth through wells.
These wells are drilled to a depth of up to two miles into the earth. Geother-
mal sources are used to produce electrical energy in certain regions of the
western United States.
W ind systems have also been considered for producing electrical en-
ergy. However, winds are variable in most parts of our country. This fact
causes wind systems to be confined to being used with storage systems, such
as batteries. It is possible that wind machines may be used to rotate small
generators which could, potentially, be located at a home. However, large
amounts of power would be difficult to produce by this method.
Another energy source which has some potential for future use is mag-
netohydrodynamics (MHD). The operation of an MHD system relies upon the
flow of a conductive gas through a magnetic field, thus causing a direct cur-
rent (DC) voltage to be generated. The electrical power developed depends
upon the strength of the magnetic field that surrounds the conductive gas,
and on the speed and conductivity of the gas. At the present time, only
small quantities of electrical energy have been generated using the MHD
principle; however, it does have some potential as a future source of electri-
cal energy.
Still another possible energy source is nuclear fusion. This process has
not been fully developed, due to the extremely high temperatures that are
produced as fusion of atoms takes place. A fusion reactor could use tritium or