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12.15: Energy from Biomass

Difficulty Level: At Grade Created by: CK-12
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Why is algae better than corn for biofuel?

Algae is a better alternative for producing biofuel than traditional crops because crops could be used for other things, like feeding people.


Biomass is the material that comes from plants and animals that were recently living. Biomass can be burned directly, such as setting fire to wood. For as long as humans have had fire, people have used biomass for heating and cooking. People can also process biomass to make fuel, called biofuel. Biofuel can be created from crops, such as corn or algae, and processed for use in a car (Figure below). The advantage to biofuels is that they burn more cleanly than fossil fuels. As a result, they create less pollution and less carbon dioxide.

Ethanol information sign in California

Biofuels, such as ethanol, are added to gasoline to cut down the amount of fossil fuels that are used.

Organic material, like almond shells, can be made into electricity. Biomass power is a great use of wastes and is more reliable than other renewable energy sources, but harvesting biomass energy uses energy and biomass plants produce pollutants including greenhouse gases.

Find out more at http://science.kqed.org/quest/audio/how-green-is-biomass-energy/.

Cow manure can have a second life as a source of methane gas, which can be converted to electricity. Not only that food scraps can also be converted into green energy.

Find out more at http://science.kqed.org/quest/video/from-waste-to-watts-biofuel-bonanza/.

Food that is tossed out produces methane, a potent greenhouse gas. But that methane from leftovers can be harnessed and used as fuel. Sounds like a win-win situation.

Find out more at http://science.kqed.org/quest/audio/power-up-with-leftovers/.

Consequences of Biomass Use

In many instances, the amount of energy, fertilizer, and land needed to produce the crops used make biofuels mean that they often produce very little more energy than they consume. The fertilizers and pesticides used to grow the crops run off and become damaging pollutants in nearby water bodies or in the oceans.

To generate biomass energy, break down the cell walls of plants to release the sugars and then ferment those sugars to create fuel. Corn is a very inefficient source; scientists are looking for much better sources of biomass energy.

See more at http://www.kqed.org/quest/television/biofuels-beyond-ethanol.

Algae Biofuels

Research is being done into alternative crops for biofuels. A very promising alternative is algae. Growing algae requires much less land and energy than crops. Algae can be grown in locations that are not used for other things, like in desert areas where other crops are not often grown. Algae can be fed agricultural and other waste so valuable resources are not used. Much research is being done to bring these alternative fuels to market. Many groups are researching the use of algae for fuel.

Many people think that the best source of biomass energy for the future is algae. Compared to corn, algae is not a food crop, it can grow in many places, it's much easier to convert to a usable fuel, and it's carbon neutral.

Find out more at http://science.kqed.org/quest/video/algae-power/.


  • Biofuels are useful because they are liquid and can go into a gas tank unlike many other types of alternative energy.
  • Algae is the focus of much research because it is a very promising alternative to traditional crops for biofuels.
  • Biofuels have been used for as long as people have been burning wood for warmth or to cook their food.


Use this resource to answer the questions that follow.

1. How much gas is produced from corn?

2. What was the Model T designed to run on?

3. Why are cell phones forbidden in the factory?

4. How much ethanol does the factory produce?

5. Is corn an efficient energy source? Explain your answer.


1. What are the advantages of algae over other sources of biofuels?

2. Why are some crops, like corn, not necessarily a good source of biofuels?

3. How can an energy source produce very little energy more than the energy it takes to produce it?

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biofuel A fuel made from living materials, usually crop plants.

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Difficulty Level:
At Grade
Date Created:
Feb 24, 2012
Last Modified:
Aug 21, 2016
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