Alternative Energy Resources TEK 5.7C Identify alternative energy resources 
such as wind, solar, hydroelectric, geothermal, 
and biofuels. Alternative Energy Resources Alternative Energy Resources are energy resources that 
can be used instead of nonrenewable resources or 
fossil fuels. They produce energy without the 
consequence of the burning of fossil fuels (coal, oil, 
natural gas) to provide electricity, heat, and run cars. There are 5 types of Alternative Energy Resources -biofuel -hydroelectric -geothermal -wind -solar

Solar Power: Solar energy is energy that comes from the sun. This energy gives 
us light and heat. We can also use sunlight to make electricity. Solar cells are one way to use the sun's energy. Solar cells change 
sunlight to electricity. Lots of cells are put together in a solar 
panel. When sunlight hits the panel, it generates electricity. Many 
people are putting solar panels on their roofs to help power their 
homes and businesses. What if there is no sun? Since there is no sun at night you can purchase a battery that can 
store electricity.

You can find solar panels in large fields like at the Denver 
International Airport.

You also find solar panels on the roofs of buildings and homes.

Advantages: Solar energy will not run out, and does not pollute. Disadvantages: It takes a lot of space, and is expensive to buy and 
install. It also needs bright light to work.

Wind Power How can we use wind to make electricity? The wind blows directly onto the blade of the turbine, 
much like wind turns a pinwheel. The turbine turns the 
generator to make electricity. Turbines are built in windy areas - across open plains, on 
smooth hills, near shorelines, and between mountain gaps. Click the wind turbine 
to take a tour of a wind 
farm.

A wind farm is an area where huge metal fans are set 
up to catch the wind. Wind turns the blades connected 
to a generator which makes electricity. This is the 
opposite of a regular fan. Wind energy does not pollute, but wind turbines are 
expensive, and the strength of the wind isn't constant. 
Some areas are not windy enough to use wind power. 
Electrical energy produced by wind is more expensive 
than from other sources.

Hydroelectric Power What is hydroelectric power? Hint...hydro means water. Hydroelectric power is electricity produced by moving water. Falling water can be very forceful. River water can fall over waterfalls and 
be used to make electricity. Hydroelectric power plants can be built at the 
bottom of a dam to take advantage of the high pressure of the water at the 
bottom of the reservoir (lake). The water is funneled through a tunnel. The 
pressure of the water turns the blades of the turbine, which turns a 
generator making electricity. Fun fact:One of the earliest 
generating stations was 
built in 1896 at the bottom 
of Niagara Falls.

Rivers can be used as an alternative energy resource. A dam could be built across the river. Water 
moving through the dam turns a generator which 
makes electricity. We call this hydroelectric power.

Hydroelectric Dam

Biofuel Biofuel is fuel that comes from plants. Plants contains stored energy from the 
sun. Plants absorb the sun's energy in a process called photosynthesis. The 
chemical energy in plants gets passed on to animals and people that eat them. Today, we can burn garbage in 
special waste-to-energy plants 
and use its heat energy to make 
steam to heat buildings or to 
generate electricity. There are about 90 waste-to-
energy plants in the United 
States. These plants generate 
enough electricity to supply 
almost 3 million households.

Biofuels are made in two ways Biofuels are made in two ways. One way is to use plants that are 
high in sugar or starch and make them into ethanol. Corn, sugar 
cane, and sweet sorghum are often used to make ethanol. Ethanol 
can be used like gasoline in some car engines. More often, it is 
combined with gasoline to make a cleaner fuel. Another way is to use plants that contain lots of vegetable oil and 
use them to make biodiesel. Certain palm trees and soybeans are 
often used in this way. Biodiesel can be used in diesel engines. 
Pure vegetable oil can also be used in certain engines. Both are 
usually more expensive than the fossil fuels that they replace, but 
they are also cleaner-burning fuels, producing fewer air pollutants.

Fryer Flyer The "Fryer Flyer" is a green school bus that runs on waste vegetable oil (WVO - post-
consumer grease which is often disposed of improperly, clogging our sewers and 
waste water treatment facilities). Dallas County Schools collects the WVO that is 
donated by local restaurants and food manufacturers. They then transport it to their 
plant, where it is cleaned and contaminants are removed through a filtering process. 
Once the WVO is clear of debris and foreign substances, it is ready to be used as fuel 
or processed into biodiesel, also known as B100. The use of WVO and B100 reduces 
the production of greenhouse gases, particulate matter and other pollutants which are 
harmful to the environment.

Biofuels This bus runs on soybean bio-diesel. Bio-diesel is made from 
vegetable oils, animal fats or recycled greases.

Geothermal What is geothermal energy? Geo means Earth and thermal means heat. Geothermal energy is heat from the 
Earth's hot interior. In some places the Earth's heat can 
make steam for example near volcanos or 
near moving earth plates. Sometimes the 
steam can be taken directly from the earth.

Geothermal power plants use deep wells to tap into underground 
reservoirs of hot water. These wells bring the hot water to the 
surface. There it produces steam to generate electricity. The 
cooled water is returned underground to be heated again. Then, 
the cycle starts over.

Geothermal Energy