406
Electricity and Basic Electronics
their crops on all their land, except for a small
section around each tower. This is not true of
other types of power generation sources, such
as power plants.
Additional Research
Another area of research for alterna-
tive energy sources being examined is tidal
currents and tidal bores. Tides usually occur
two times every day. That means the water
moves out twice and moves back in twice
each day. A tidal bore is a rapid increase in
the leading edge of water returning up a river
because of tidal action. Tides can be as high as
20´ or more from low to high tide. Tidal bores
have been found to reach 30′ high in some
rivers in China.
There are companies that have mapped
the tides all around the world at different
times of the year. These companies have
begun installing generating equipment at
specifi c locations where the tides can produce
the most electricity. If you examine this area
of research, you can determine exactly where
these locations are found.
Summary
• Some ways to conserve energy in the
area of lighting are turning on lights that
are necessary and turning them off when
they are no longer needed and using
energy effi cient bulbs.
• Fluorescent bulbs can provide the same
amount of light at a lower wattage than
incandescent bulbs.
• Energy effi cient appliances can be chosen
by looking at their rating and fi nding the
model with the best rating.
• Some energy effi ciency rating scales
show how much energy an appliance
uses compared to others in its class;
others use an objective scale that rates
how effi cient an appliance is according to
some criteria.
• Buildings are insulated to keep the outside
air from affecting the temperature of the
air inside the building.
• Double pane and triple pane are energy-
effi cient types of windows.
• A geothermal heating system extends
far underground and uses the steady
temperature of the earth to keep a home
warm in the winter and cool in the
summer.
• Solar energy and wind energy are two
alternative resources to oil, coal, and
other nonrenewable resources.
• The use of solar energy to produce
electricity is called photovoltaics.
• Photovoltaic cells convert solar energy
into electrical energy.
• Some of the functions of an inverter in
a photovoltaic system include turning
the system on after sunrise, monitoring
the electricity produced, and turning the
system off after sunset.
• Most states offer incentives and rebates
to people and businesses that install
energy-saving devices.
• Wind turbines are very tall, which allows
them to catch the faster wind speeds
found at higher altitudes.
• The wind turbine produces electrical
energy.
• When the wind blows, it turns the blades
on a wind turbine, which is attached to
the armature of the generator.
• Developers who are building wind
turbines build in areas with high winds
and a lot of windy days.