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Biofuels are one solution to reducing humans’ use of non-renewable fossil fuels and to reducing the greenhouse gases that result from their burning. In this activity, students will assess the sustainability of different biofuels. Students will be asked to evaluate how the life cycle (production, transport, and use) of each biofuel feedstock impacts the economy, the environment, and society. Finally, students will learn about bioelectricity and how converting biomass to electricity may be the more efficient way to fuel cars in the 21st century.

Essential questions

  • What are the different feedstocks that can be used to produce biofuels?
  • What are the properties of an ideal biofuel?
  • Which biofuel is most sustainable? Least sustainable?
  • Which biofuel feedstock do you recommend be used for biofuel production?
  • What is bioelectricity?

Teacher planning

Time required

  • Time for independent research (in class or as homework)
  • Time for in-class presentations and discussion (90 minutes)

Materials/resources

  • Internet access or other current biofuel resources (books, articles, brochures, etc.)
  • Bioelectricity article of choice (see Procedure Step 8), one per student
  • Sustainability of biofuels: Comparison chart
    Open as PDF (10 KB, 1 page)
  • Diagram of the biofuels life cycle:

Pre-activities

This activity should be preceded by a discussion of sustainability. Students should be familiar with the definitions for and examples of renewable and non-renewable energy sources.

Activities

  1. Introduce students to the different classes of biofuels:

    • First-generation biofuels are made from food crops (seeds or grains) or animal feedstocks. Crops such as corn, soy, palm, and sugarcane have sugars, starches, and oils that can be transformed into biofuels. Examples: ethanol, biodiesel, biogas (e.g., methane).
    • Second-generation biofuels are made from non-food crops. These fuels are made from lignocellulosic biomass which includes switchgrass and agricultural waste (wheat stalks). Example: cellulosic ethanol.
    • Third-generation biofuels are made from algae and other plants that have been genetically engineered to yield biofuels.
  2. Using the diagram of the biofuels life cycle, introduce students to the biofuels life cycle. Ask them if any steps appear to be missing from the diagram. (YES! Feedstocks are typically pre-processed prior to conversion (e.g., seeds are crushed for biodiesel) and there is a transportation step to distribution to consumers).
  3. Invite students to work in pairs or small groups and assign each group one of the following biofuels (the feedstock is indicated in parentheses):
    • Corn-based ethanol (corn)
    • Cellulosic ethanol (switchgrass)
    • Biodiesel (soybean)
    • Biodiesel (palm)
    • Biodiesel (waste animal fat or vegetable oil)
    • Algal
  4. Either in class or as a homework assignment, students should be directed to conduct independent research to answer the following questions about their assigned biofuel. Students should prepare to present their findings to the class. Below are sample questions your students could answer to guide their research:
    • How does this biofuel compare to gasoline/diesel?
    • Net energy yield?
    • GHG emissions?
    • Production costs?
    • To what extent is this biofuel being used currently in the US? Globally?
    • What are the factors that limit production of this feedstock (if applicable)?
    • Summarize any relevant government regulations pertaining to your biofuel.
    • Describe any potential roles of biotechnology in improving your biofuel.
    • What by-products are produced as a result of converting this feedstock into a biofuel?
    • Describe the market for any by-products.
    • Is your biofuel making news headlines? Why?
  5. Once students have compiled some basic facts about their biofuel, invite them to consider the life cycle of their biofuel and assess the sustainability of producing this feedstock and converting it into a biofuel. Direct students to answer the following questions (Adapted with permission from the lesson “Is It Sustainable?” from Engaging Students through Global Issues, by Facing the Future, (c) 2006) and review current news articles in evaluating the sustainability of their assigned biofuel. Students may enjoy drawing the life cycle of their assigned biofuel on large sheets of paper in preparation for their presentation to the class. Alternatively, you may choose to ask students to summarize their analysis in writing and include a visual description of the life cycle of their biofuel.
    • What are the positive and negative impacts on the environment?
      • What resources are used in the life cycle of this biofuel?
      • Are the resources used able to be renewed or regenerated?
      • Are plants and/or animals damaged during the production of this biofuel?
      • Is biodiversity maintained?
      • Does biofuel production cause air pollution, water pollution, or soil erosion?
      • Does biofuel production generate waste? If so, what happens to the waste?
      • Will biofuel production help to conserve natural resources (air, water, land)?
    • What are the positive and negative impacts on the economy?
      • What is the economic impact of biofuel production?
      • Does biofuel production create meaningful and satisfying work for individuals?
      • Does biofuel production allow people to do their jobs more efficiently?
      • Does biofuel production contribute to a community’s economic development?
      • Does biofuel production rely on products or services that have negative effects on the environment or society?
    • What are the positive and negative impacts on society?
      • Does biofuel production contribute to people’s quality of life?
      • Do some people benefit from biofuel production at the expense of others?
      • Does biofuel production affect people’s cultures?
      • Are individuals and communities involved in making decisions about biofuel production?
      • Does biofuel production offer more options/opportunities to certain groups of people than others?
  6. Ask student groups to briefly present their findings to the class. You may consider asking the students to create a short PowerPoint presentation or design a poster about their biofuel. One teacher who piloted this lesson had students go on a “gallery walk” and view each group’s biofuel poster. Students can complete the “Sustainability of Biofuels: Comparison Chart” as they hear from each group.
  7. Conclude this activity with an in-class discussion. You may consider asking any or all of the following questions depending on student responses:
    • Based on our findings, what are the properties of an ideal biofuel?
    • Based on our findings, which biofuel appears to be most sustainable? Least sustainable?
    • Based on our findings, which biofuel feedstock do you recommend be used for biofuel production?
    • Which generation of biofuels has the greatest promise to power our future energy needs?
  8. Based on their analyses, students may come to the conclusion that even biofuels aren’t the perfect solution. A study released in May 2009 suggests that biomass converted into electricity is more efficient than converting corn into ethanol for use in vehicles (See Driving on Biomass in news section below). Invite students to read one of the following documents related to this report (listed in order of increasing reading difficulty).
  9. Conclude this lesson by asking the class to discuss the overall sustainability of converting biomass to electricity (”bioelectricity”) compared to biofuels. Which do they think has more promise, using biofuels or bioelectricity to meet our transportation needs?

Culminating activities

Guest speakers/tours

  • Invite someone who works in the biofuel industry to speak to the class.
  • Ask a local corn or soybean farmer to speak to the class about how the biofuel industry is impacting farming.
  • Invite a local government representative to discuss the adoption or potential adoption of biofuels for use in municipal vehicles.

Research-based writing assignments

  • Have students investigate the role of government in addressing the following issue: “Huge demand for biofuels has created tension between using land to produce fuel and using it for food.” (From “A New, Global Oil Quandary: Costly Fuel Means Costly Calories” – see news articles section below).
  • Have students investigate the role of government in setting biofuel standards: “‘Different biofuels vary enormously in how eco-friendly they are,’ said William Laurance, a staff scientist at the Smithsonian Tropical Research Institute. ‘We need to be smart and promote the right biofuels.’” (From “Europe May Ban Imports of Some Biofuel Crops” – see news articles section below).
  • Have students investigate the economic impact of the following issue: “Huge demand for biofuels has created tension between using land to produce fuel and using it for food” (From “A New, Global Oil Quandary: Costly Fuel Means Costly Calories” – see news articles section below.

Modifications and alternative assessments

Students with special needs

Place students in mixed-ability pairs for activity completion.

Academically gifted

  • Students can work individually.
  • Ask students to summarize their biofuel evaluation in writing.
  • Ask students to evaluate the use of biofuels in their local community. Are biofuels available to consumers? Which ones? Are municipal vehicles utilizing biofuels? To what extent?

Resources

News articles

Websites

Critical vocabulary

First-generation biofuels
Fuels that are made from food crops (seeds or grains) or animal feedstocks. Crops such as corn, soy, palm, and sugarcane have sugars, starches, and oils that can be transformed into biofuels. Examples: ethanol, biodiesel, biogas (e.g., methane).
Second-generation biofuels
Fuels that are made from non-food crops. These fuels are made from lignocellulosic biomass which includes switchgrass and agricultural waste (wheat stalks). Example: cellulosic ethanol.
Third-generation biofuels
Fuels that are made from algae and other plants that have been genetically engineered to yield biofuels.

Acknowledgements

Thanks to the following individuals who thoughtfully reviewed and/or piloted this lesson:

  • Phil Cox, Science Teacher, Jordan Matthews High School
  • Lyle Estill, Co-founder, Piedmont Biofuels
  • Christie Hinson, Project Director, NC Civic Education Consortium, UNC School of Government
  • Dacia Harris, Science Teacher, Asheville High School
  • Jessica Hoffmire, Educator, NC Zoological Park
  • Leanna Kendall, Science Teacher, McDougal Middle School
  • Andrew McMahan, Bio-fuels Coordinator, Central Carolina Community College

  • North Carolina Essential Standards
    • Science (2010)
      • Biology

        • Bio.2.2 Understand the impact of human activities on the environment (one generation affects the next). Bio.2.2.1 Infer how human activities (including population growth, pollution, global warming, burning of fossil fuels, habitat destruction and introduction...
      • Earth and Environmental Science

        • EEn.2.2 Understand how human influences impact the lithosphere. EEn.2.2.1 Explain the consequences of human activities on the lithosphere (such as mining, deforestation, agriculture, overgrazing, urbanization, and land use) past and present. EEn.2.2.2 Compare...
        • EEn.2.8 Evaluate human behaviors in terms of how likely they are to ensure the ability to live sustainably on Earth. EEn.2.8.1 Evaluate alternative energy technologies for use in North Carolina. EEn.2.8.2 Critique conventional and sustainable agriculture and...

North Carolina curriculum alignment

Science (2005)

Grade 9–12 — Biology

  • Goal 5: The learner will develop an understanding of the ecological relationships among organisms.
    • Objective 5.03: Assess human population and its impact on local ecosystems and global environments:
      • Historic and potential changes in population.
      • Factors associated with those changes.
      • Climate change.
      • Resource use.
      • Sustainable practices/stewardship.

Grade 9–12 — Earth/Environmental Science

  • Goal 1: The learner will develop abilities necessary to do and understand scientific inquiry in the earth and environmental sciences.
    • Objective 1.06: Identify and evaluate a range of possible solutions to earth and environmental issues at the local, national, and global level including considerations of:
      • Interdependent human and natural systems.
      • Diverse perspectives.
      • Short and long range impacts.
      • Economic development, environmental quality and sustainability.
      • Opportunities for and consequences of personal decisions.
      • Risks and benefits of technological advances.
  • Goal 2: The learner will build an understanding of lithospheric materials, tectonic processes, and the human and environmental impacts of natural and human-induced changes in the lithosphere.
    • Objective 2.06: Investigate and analyze the importance and impact of the economic development of earth's finite rock, mineral, soil, fossil fuel and other natural resources to society and our daily lives:
      • Availability.
      • Geographic distribution.
      • Conservation/Stewardship.
      • Recycling.
      • Environmental impact.
      • Challenge of rehabilitation of disturbed lands.
    • Objective 2.07: Analyze the sources and impacts of society's use of energy.
      • Renewable and non-renewable sources.
      • The impact of human choices on Earth and its systems.