Grade Level & Subject: 9-12; Chemistry/Economics
Length: 1 Class Period
After completing this lesson, students will be able to:
- Describe what biofuels are and what are their advantages and disadvantages
- Explain the chemistry of biodiesel and what components are required to make it
- Analyze the feasibility of switching to renewable fuels like biodiesel
- Understand the social and environmental implications of using biofuels
National Standards Addressed:
This lesson addresses the following National Science Education Standards.
- Content Standard: NSS-EC.9-12.3 ALLOCATION OF GOODS AND SERVICES
As a result of activities in grades 9-12, all students should develop understanding of:
- Comparing the benefits and costs of different allocation methods in order to choose the method that is most appropriate for some specific problem can result in more effective allocations and a more effective overall allocation system.
- Content Standard: NSS-EC.9-12.4 ROLE OF INCENTIVES
As a result of activities in grades 9-12, all students should develop understanding of:
- Acting as consumers, producers, workers, savers, investors, and citizens, people respond to incentives in order to allocate their scarce resources in ways that provide the highest possible returns to them.
- Content Standard: NS.9-12.2 PHYSICAL SCIENCE
As a result of activities in grades 9-12, all students should develop understanding of:
- Structure of atoms
- Structure and properties of matter
- Chemical reactions
- Access to computers with internet access
- Reproducible #1 – The Process of Making Biodiesel
- Reproducible #2 – Transesterification
- Reproducible #3 – Biodiesel Plants
- Reproducible #4 – Biodiesel Research Worksheet
Students will be assessed through the following activities:
- Understanding of biodiesel chemical process
- Completion of biodiesel economic analysis activity
- Participation in class discussion
- Biofuel: A fuel (as wood or ethanol) composed of or produced from biological raw materials.
- Carbon Neutral: The characteristic of a particular energy source in which as much carbon is absorbed during production as when combusted
- Catalyst (chemistry): A substance that enables a chemical reaction to proceed at a usually faster rate or under different conditions (as at a lower temperature) than otherwise possible
- Cost-Benefit Analysis: An analysis of the cost effectiveness of different alternatives in order to see whether the benefits outweigh the costs
- Potassium Hydroxide: A white deliquescent solid KOH that dissolves in water with much heat to form a strongly alkaline and caustic liquid and is used chiefly in making soap and as a reagent 
- Renewable Fuel: A fuel that is capable of being replaced by natural ecological cycles
- Sustainability: the quality of using a resource so that it is not depleted or permanently damaged.
- Transesterification: A reversible reaction in which one ester is converted into another (as by interchange of ester groups with an alcohol in the presence of a base)
- Triglyceride:Any of a group of lipids that are esters formed from one molecule of glycerol and three molecules of one or more fatty acids, are widespread in adipose tissue, and commonly circulate in the blood in the form of lipoproteins
Biofuelsare often idealized as the homegrown solution to the world’s energy insufficiencies. They allow for countries to produce their own steady source of fuel. Not only does this provide jobs for the nation’s workforce, but it also limits reliance on foreign entities for energy needs. However, the recent surge for a more biofuel focused energy industry is not necessarily a novel revolution despite its portrayal as one in the media. Biofuels, particularly biodiesel, have a strong pedigree. The inventor of the diesel engine, Rudolf Diesel, envisioned a world in which his engines would be run on strictly peanut oil and other plant derivatives. In this utopia, farmers would grow their own fuel to power their machinery. Unfortunately, his vision was never realized. Massive oil production at the beginning of the 20th century caused petroleum prices to drop dramatically, making petroleum diesel engines a more economical choice. When oil prices escalated, people sought means to become producers of their own automobile fuel. As a result, biodiesel was spurred into existence. Currently it remains a relatively small industry. Businesses do exist that create and distribute biodiesel to educational institutions and transportation-reliant companies, but there are also numerous home brewers all across the world that create batches of biodiesel for personal use.
The reason for this is because biodiesel is a fairly simple fuel to make. It requires only a few chemicals (methanol/ethanol, potassium/sodium hydroxide, and vegetable oil), and the equipment necessary to make it is pretty standard. Biodiesel is made through a chemical process known as transesterification. It uses potassium or sodium hydroxide as the catalyst to promote the reaction between an alcohol (methanol or ethanol) and the fat (triglycerides). Transesterification is given its name because during the process the triglyceride esters lose their glycerol and a methyl group from the methanol is transferred to replace it (see Reproducible #2 – Transesterification)
Another advantage of biodiesel is that it can be used in most standard diesel engines without any prior modification to the engine. Unlike, straight vegetable oil (SVO), which is the preferred fuel choice for some groups of dedicated fuel pioneers, diesel engines running on biodiesel do not require additional components to make the engine suitable to run on it. Additionally, biodiesel will not cause harm to a diesel engine. Properly synthesized biodiesel will not build up scum in the engine or deteriorate parts unlike SVO. In fact, since biodiesel is a solvent, many biodiesel enthusiasts praise its cleaning power and how it removes the residual gunk in their engines from using petroleum diesel.
Biodiesel has been made and tested from numerous plants that produce oils. A short list of plants that can produce biodiesel viable oils includes peanut plants, sunflowers, palm trees, and algae. Because biodiesel is so versatile, many businesses that use diesel vehicles such as farmers and educational institutions will run their machinery or buses on biodiesel blends. Blends of biodiesel are labeled with a straightforward format, B##, where “B” stands for biodiesel and the “##” signifies the percentage of biodiesel in the fuel blend. Any blend less than B100 uses petroleum diesel for the remaining percentage. The University of Maryland's shuttle buses run on either B5 or B20 depending on the season.
One disadvantage to biodiesel is that it does not perform as well in cold weather. During cold months, biodiesel will begin to crystallize and solidify at a higher temperature than petroleum diesel. Having a lower blend of biodiesel lowers the solidifying point relative to B100, which is why the University of Maryland uses a B5 blend during the winter and a B20 blend in the summer. Biodiesel made from some oils are better suited for cold weather than other oils. Biodiesel also has an approximately 11% lower energy content compared to its petroleum counterpart. Subsequently, engines running on biodiesel will have lower fuel economy depending on the blend used. Nonetheless, this drop in fuel economy is substantially less significant when compared to ethanol (E85) and gasoline. E85 produces 25-30% lower miles per gallon than gasoline. Another disadvantage of biodiesel is that it increases nitrogen oxide compounds by up to 10%. Nitrogen oxide is a dangerous chemical because it contributes to the formation of ozone and acid rain. On the other hand, switching over to biodiesel greatly reduces other pollutants such as hydrocarbons, carbon monoxide, and particulate matter.10 Using a 100% blend of biodiesel completely annuls sulfate production.
Biodiesel can be made in the classroom. However, making it will require purchasing several different chemicals and access to proper safety equipment. Synthesizing biodiesel is a fairly simple process and takes about two class periods to complete. The experience can be rewarding for students (they will realize just how easy it is to make their own fuel). If you are interested in teaching your students how to make biodiesel, go to http://edu.earthday.org/resources to find Earth Day Network’s biodiesel making lesson plan.
- Bio Diesel – U.S.Department of Energy:
- Alternative and Advanced Fuels – U.S.Department of Energy:
- Bio Diesel Performance, Cost and Use– Energy Information Administration:
- BioDiesel SchoolBuses – America’s Advanced Fuel:
Teacher Preparation Steps:
- Print out all reproducibles as transparent overhead slides.
Warm-up: Natural Energy
- Ask the students what a biofuel is. Any variation of fuels created from biological matter. Categories of biofuel include solid biomass, liquid fuels, and biogases. Biofuels are often exclusively defined as originating from recently-living/renewable sources.
- What are some examples of biofuels? Biodiesel, ethanol, algae ethanol, wood/woodchips, methane
- What are some benefits of biofuels? They come from natural, renewable sources. As a result, they tend to produce fewer emissions. Unlike fossil fuels, they are also quickly replenished and can be produced locally. This reduces the need for foreign sources of fuel. Biofuels can also be carbon neutral (see next question). Most biofuels can be made from many different sources. For example, ethanol can be made from corn, sugarcane, switchgrass, and other plants.
- What does it mean for a fuel to be carbon neutral? Over the course of its production (including plant growth) the fuel intakes as much carbon dioxide as is released when it is combusted for energy. In general, carbon neutral refers to releasing a net of zero carbon dioxide into the atmosphere.
- Tell students that this lesson plan will focus primarily on biodiesel. They will research the viability of biodiesel as widely used fuel. Tell the students about the history of biodiesel:
When he first invented the diesel engine, Rudolf Diesel envisioned a world in which his engines would run on vegetable oils and farmers could produce their own fuel from crops. At the 1900 World Fair, he ran one of his early diesel engines on peanut oil. However, due to a marked increase in fossil fuel mining, petroleum became the standard fuel for diesel engines. When concerns of fossil fuel reliance were raised, vegetable oil blends were tested for their viability as a fuel source for diesel engines. The tests found that straight vegetable oil (SVO) caused the engines to fail. When the oil was transesterified with alcohols the fuel performed well and did not develop the same issues as SVO. As a result, biodiesel was born and the legacy of Rudolf Diesel’s dreams live through it.8
Activity One: Biodiesel at School
In this activity, students will pick a type of crop the yields biodiesel producible oil. They will then analyze what it would take to switch their school’s energy dependence to biodiesel.
- Give students a brief introduction of how biodiesel is made. Display Reproducible #1 - The Process of Making Biodiesel on a projector. Explain to the students that biodiesel is made when triglycerides (the vegetable oil) is combined with an alcohol (methanol) and a catalyst is added (potassium hydroxide). The process is called transesterification. Note that the volumes and masses noted next to each chemical are the approximate amount of chemical needed for a 1L batch of biodiesel. These numbers will be used in a future portion of the activity.
- Display the Reproducible #2 – Transesterfication to show them what is happening from a chemistry perspective. Point out that that the fatty acids (R group) in the triglycerides detach from the glycerol (single bonded carbons on the left side) and is replaced with the methyl (CH3) from the methanol. The hydroxyl group from the methanol will then attach to the glycerol. For the purpose of making biodiesel, the glycerol is considered waste product and has no use. Ask students what the role of a catalyst is. It lowers the activation energy of the reaction allowing it proceed faster. Unlike its name implies, a catalyst does not technically begin a chemical reaction.
- Next, tell students to think about all the things in their school that fuel may be used for. To power school buses, generators, and staff vehicles.
- Then ask students to think about how much fuel must be used to power those things. Tell the students that they will be researching what it would take to switch their school over to 100% biodiesel power.
- Ask students to split up into groups of 2-3. Show Reproducible #3 – Biodiesel Plants using an overhead projector, and then ask each group to pick a type of plant to research. There may be overlap in plant selections if more than one group chooses a particular plant to research.
- Students will then figure out how much fuel is needed to power their school for a year. Using that information, they will research the particular plant that their group has picked and determine how many acres of plant must be dedicated to the production of that plant so that the oil from it can be used to produce biodiesel for the school.
- Pass out Reproducible #4 – Biodiesel Research Worksheet and ask students to use the worksheet to help guide them. Estimation and averages may be used.
- When students have completed the worksheet, ask the class the reconvene and call on groups to present their findings.
Wrap Up: Future of Biodiesel
- What implications do you think biodiesel has on the future of the energy industry? The car industry? There may be more of an emphasis towards mass producing biodiesel. Potential corporate takeover of the biodiesel industry. Car manufacturers may produce more diesel cars. They may design diesel engines to be more attuned to biodiesel fuel.
- What impact do you think biodiesel will have on the environmental movement? It will help to create a transition to a cleaner energy market. It may be a small step that helps to evoke a larger surge that will green the energy industry as a whole.
- Why do you think diesel vehicles are not more popular in the American market? There is a perception that diesel vehicles are much dirtier than gasoline vehicles. This is often perpetuated by the image of a dump truck (or any other large industrial vehicle) spewing out clouds of black smoke from its exhaust pipe.
- Right now, the biodiesel market is predominantly composed of do-it-yourself biodiesel producers. Corporate controlled manufacturers exist, but do not dominate the biodiesel market like petroleum corporations monopolize the oil industry. Do you think this is a good market model, or do you think businesses should have a larger presence in the biodiesel industry? Answers will vary. Some may argue that this is a poor market model because it hinders expansion into the greater market. Others may say that this is a good model because it allows for the individual/small groups to determine availability, demand, price etc. In this way, small startups can flourish which may have a stronger connection to their clientele base than would a national corporation. Some homebrewers would also argue that their biodiesel is higher quality than the fuel made by large companies.
- If you had $50 million to invest in a particular automobile energy technology and had to pick between electric vehicles or biofuel powered vehicles, which one would you choose? Why? Answers will vary. Students could pick electric vehicles because it is cleaner and would help build the solar and wind energy industries. Students may pick the biofuel powered vehicles because they will help to create a more carbon neutral energy industry and a stable domestic energy market that will provide jobs for many workers.
- Research It!Ask students to choose a biofuel (that is not biodiesel) that is of particular interest to them, and have them do a comprehensive analysis of their biofuel’s viability as a fuel source. Ask them to research energy production potential, transportation and manufacturing costs, and social and political implications. They will need to create a marketing strategy to pitch their particular biolfuel to convince the general public to support or oppose investment in the biofuel. They can create brochures, radio advertisements, television commercials, etc. This extension project can be done individually or in groups.
- Make It!If students are interested in making biodiesel, provide them the resources for making it on their own or start a campaign to make biodiesel at your school. Biodiesel can be made from waste vegetable oil from the cafeteria, and it can be used to power the school buses that take students to and from home. Earth Day Network's Education Department is currently working with various school districts across the United States to implement biodiesel making apparatuses which will be used by the schools. For more information on these endeavors and possible educational grants for projects like this, please visit our website: http://edu.earthday.org/resources.
With this lesson, students will have learned about biofuels, the purpose they fulfill in today’s economy, and the potential they have to shape the future. Students will have developed their analytical thinking skills to contemplate the advantages and disadvantages of biofuels, in particular, biodiesel. They will understand what kind of investments must be made to switch to full dependence on biodiesel. Students will also have gained a fundamental understanding of the chemical process that facilitates biodiesel synthesis. Discussion and extension activities will help students to view renewable fuels from a holistic approach that considers all the social, economical, and environmental impacts.
LESSON PLAN CREDITS
Wesley Tse – Author
Education Intern, Earth Day Network
Josh Volinsky – Editor
Green Schools Coordinator, Earth Day Network
Holzman, David C. "The Carbon Footprint of Biofuels: Can We Shrink It Down to Size in Time?" Environmental Health Perspective 116.6 (2008): 246-52. PubMed Central. Web. 20 Apr. 2011. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2430251/
“Catalyst Entry.” Merriam-Webster Online Dictionary. Retrieved 18 March 2011 from http://www.merriam-webster.com/dictionary/catalyst
"Cost-Benefit Analysis." WordNet Search 3.0. Princeton University. 2 May 2011. http://wordnetweb.princeton.edu/perl/webwn?s=cost-benefit%20analysis
“Potassium Hydroxide Entry.” Merriam-Webster Online Dictionary. Retrieved 2 May 2011 from http://www.merriam-webster.com/dictionary/potassium%20hydroxide
“Renewable Entry.” Ibid. Retrieved 2 May 2011 from http://www.merriam-webster.com/dictionary/renewable
“Sustainable Entry.” Ibid. Retrieved 2 May 2011 from http://www.merriam-webster.com/dictionary/sustainable
“Transesterification Entry.” Ibid. Retrieved 18 March 2011 from http://www.merriam-webster.com/medical/transesterification
“Triglyceride Entry.” Ibid. Retrieved 18 March 2011 from http://www.merriam-webster.com/dictionary/triglyceride
"Transportation." Campus Sustainability · University of Maryland. University of Maryland Office of Sustainability, 2010. Web. 02 May 2011. http://www.sustainability.umd.edu/content/campus/transportation.php.
"Biodiesel Q&A." IdahoOffice of Energy Resources. Idaho Office of Energy. Web. 02 May 2011. http://www.energy.idaho.gov/renewableenergy/biodiesel_qa.htm.
Radich, Anthony. "Biodiesel Performance, Costs, and Use." Biodiesel Performance, Costs, and Use. Energy Information Administration. Web. 02 May 2011. http://www.eia.doe.gov/oiaf/analysispaper/biodiesel/.
Nelson, Richard. Biodiesel In Kansas. Rep. Kansas Energy Council, 15 May 2007. Web. 2 May 2011. http://kec.kansas.gov/reports/Biodiesel_in_Kansas_FINAL.pdf.