Much of the energy we use is produced in large power plants. Those
plants extract the energy from some source, such as coal, and change
that energy into the energy of choice, electricity. Then that electrical
energy can be transported to where it is needed. Contrary to what
you might expect, the source energy goes though a number of changes
before being turned into electrical energy, leading to a chain of
2001, total US generation of electricity was 3,777 billion kilowatt-hours.
The % of electricity produced from each source of energy is shown
below in a pie chart.
coal is burned in a boiler which produces steam. The steam is run
through a turbine which turns a generator which produces electricity.
A turbine is like a fan in reverse, with many vanes or blades, where
the steam is used to make the turbine turn or rotate rapidly. A
generator is a huge magnet that is turned by the turbine. As the
magnet turns inside a coil of wire, electricity is produced. So,
the energy chain for this power plant would look like this:
The huge magnet
assists in changing the mechanical energy into electrical energy,
but the mechanical energy does not actually turn into magnetic energy.
This is complicated since electrical and magnetic energy are so
intimately related to one another.
energy power plants, whether the source of energy is the burning
of coal, oil, natural gas, or the fissioning of uranium, follow
the same energy chain shown above.
the energy chain is different, since there is no fuel to be burned,
there is no need for the steam boiler. The gravitational energy
of the water is used to turn the turbine directly.
(Fission) Power Plants
is usually formed into pellets which are arranged into long rods,
and the rods are collected together into bundles. The bundles are
then submerged in water inside a pressure vessel or reactor. The
fission reaction is a chain reaction, each uranium atom that fissions
or breaks apart gives off two neutrons that will cause two more
atoms to fission. To prevent this, control rods made of a material
that absorbs neutrons are inserted into the bundle using a mechanism
that can raise or lower the control rods.
bundle acts as an extremely high-energy source of heat. It heats
the water and turns it to steam. The steam drives a steam turbine,
which spins a generator to produce electricity. The animation below
illustrates this process.
by Tom Chandler, OME educator, 2001-02
containment structure b) control rods c) reactor d) steam generator
e) steam line f) pump
g) generator h) turbine i) cooling water j) cooling tower k) body
energy chain for a nuclear power plant is nearly identical to the
coal power plant. The only difference is the initial or source of
energy, which is nuclear instead of chemical.
For more information
on power plants, check out the sites below: