This document discusses various alternative energy resources including biofuels, wind, solar, geothermal, and hydroelectric energy. It provides details on each type of alternative energy resource, such as how biofuels are made from plants, how wind turbines convert kinetic wind energy to electricity, and how solar panels and collectors capture energy from the sun. It also outlines some disadvantages of different alternative energy sources like how biofuels require food crops and wind turbines can kill birds. The overall document serves to educate about alternative energy resources and their benefits as substitutes for non-renewable fossil fuels.

2. Why Do We Need Alternative
Energy Resources?
 We will someday run out of non-renewable fuels like
fossil fuels.
 We need renewable ways to generate power.
 Look at the illustration in your science textbook on
page B132. It shows a generator that works with
moving water.
 We need renewable ways to turn generators. Then we
will be able to power our communities and vehicles for
a long time in the future.

3. What are Alternative Energy
Resources?
 “Alternative” means “another,” a
“different,” or a “substitute.”
 Alternative energy is a form of energy we
can use instead of using non-renewable
fossil fuels.
 Alternative energy resources are made
from renewable resources.

4. Alternative Energy
Resources
Biofuels
Wind
Solar
Geothermal
Hydroelectric

5. Biofuels
 Ethanol, produced from common crops like sugar cane,
potato, and corn
 Biodiesel, made from vegetable oil and animal fats
Both ethanol and biodiesel are added to gasoline
so we use less fossil fuel.
Two main types of fuel for transportation are
made from plants:

6. Wind Energy
• “Wind farms” have hundreds
of wind turbines with huge
propellers that spin in the
wind.
• Each of the wind turbines is
hundreds of feet tall.
• The wind turbine changes
kinetic energy from the wind
into mechanical energy that
turns a generator to make
electricity.

7. Wind turbines are really big!

8. Solar Energy
 Solar energy is energy from the sun.
 The heat energy in sunlight can cook food and
make hot water.
 The light energy in sunlight can be transformed
into electricity using solar electric panels.
A solar hot dog cooker focuses
sunlight on the food.

9. Solar electric
panels
Solar collectors for hot
water
Capturing solar energy

10. Geothermal Energy
Outer mantle 500ºC
Inner mantle 2,000ºC
Geothermal energy is heat energy stored in the Earth.
The word comes from the Greek: Geo means Earth and
thermos means heat.

11. How geothermal energy is used
Geothermal energy is used for:
 Hot springs and heated swimming pools;
 Heating greenhouses and homes through pipes and radiators;
and,
 Steam to run generators for electricity.
Austin was one of the first cities in Texas to use
geothermal energy for heating.
 The State Capitol was originally heated by geothermal water.
 Today a well in Austin supplies warm ground water (97°F) for year-
round swimming in the outdoor pool at Stacy Park.

12. Hydroelectric Energy
 Hydroelectric energy is produced by the gravitational
force of falling or flowing water.
 The falling or flowing water turns a turbine. The turbine
turns wires in a magnetic field. Electricity is then
produced in the wires.
We can control the flow
of water to make
electricity by making
dams, like Tom Miller
Dam in Austin.

13. Good News for Your Future!
 Some alternative energy
resources can reduce
pollution.
 Using renewable
resources for energy
means we will have
more resources on the
Earth.
Alternative energy
resource
development is the
job of the future.

14. Disadvantages to Biofuels and Wind
Energy
 Biofuel disadvantages
 They are made from food crops. That food could have been
used to feed people.
 The land for growing food should be used for food.
 Biofuels can only be produced when the fuel crops are growing.
 Wind disadvantages
 Wind turbines can kill birds.
 Wind turbines use a lot of land and cannot be placed near
landforms that block wind.
 Wind turbines can be noisy.

15.  Solar disadvantages
 It can be hard to store solar energy for cloudy days or night.
 It is expensive to set up solar panels.
 Geothermal disadvantages
 Most places are not near geothermal energy resources in the
Earth.
 Hydroelectric disadvantages
 Making dams on rivers destroys habitat.
 Lakes created with dams eventually fill with sediment.
Disadvantages of Solar, Geothermal, and
Hydroelectric Energy