Ideas for biofuel activities and some potentially useful references
Allen Kihm, Bob Ford, Cameron Davidson, Sam Mukasa, Scott Giorgis
(1) Effect of Biofuel production on food prices
Upper-level course on Energy and the Environment
Skills and concepts that students must have mastered
Ability to websearch for reliable information
Ability to synthesize data and reach an informed decision
How the activity is situated in the course
This should be designed as a stand-alone exercise
Content/concepts goals for this activity
Goal is for students to develop an understanding of the energy debate. The exercise should demonstrate whether biofuels based on food crops make any sense.
Higher order thinking skills goals for this activity
Data mining and analysis
Other skills goals for this activity
Skills acquired would be writing, public speaking, persuasion skills, developing an understanding of the interconnectedness of earth systems
Description of the activity/assignment
This activity would entail gathering data about food commodities (corn, soybean, etc.,) before the biofuels revolution to arrive at an informed decision on whether the industry is viable from the food production point of view.
Determining whether students have met the goals
Calculations in spreadsheets would be graded. Also, students would have to defend their positions in a presentation before their peers.
Jason Hill (2006)
(2) Making Biofuels: A Laboratory Exploration
Make a biofuel (either ethanol or biodiesel).
Analyze the "costs" of making the biofuel. ("Costs" can be energy, pollutants, etc.)
Use the biofuel to operate an internal combustion engine. (optional)
Instructions: Students will follow a recipe to make a biofuel. During the process they will focus on some aspect of the process. It could be the energy cost at each step of the process or measure the waste materials produced during the making of the biofuel. If available, use the biofuel to operate an internal combustion engine, such as student road trip in a college bus or in a maintenance vehicle.
Journey to Forever recipe and some basic chemistry for making biodiesel:
Build it Solar annotated bibliography of making biodiesel websites:
Green Living overview of how to make ethanol (lacks specific instructions):
General Information on Biofuels:
Journey to forever biofuel resource library (links to web resources):
(3) Ethanol from Corn:
Lab activity involving student opinion on whether or not the City of Minot, North Dakota should grant a tax break for a proposed ethanol facility. This example is based on an energy in versus energy out comparison (but could be adapted for cost or carbon)
Scenario: The GreenEnergy Corporation of America is proposing an ethanol facility in an Industrial park owned by the City of Minot. The issue has been brought before the City, and the decision is to let the voters decide on the project subsidy.
Prior to the class period, students are provided with a series of newspaper stories, press releases and similar items released to the general public (real world examples would be used, but altered to make this a local example). At the beginning of the class, students would be asked to cast their vote for or against the proposal and provide a short rationale for their vote (reasons such as "it's a good idea" or "I think it would be bad" are not acceptable; reasons must include a rationale for the vote).
The class vote will be tallied for the class. Next is a group discussion of the issues, and people may volunteer why they either supported of did not support the project. Discussion ideally will raise additional issues that some may not have been considered. No resolution is anticipated, but it should be interesting.
This might be a place for a concept sketch to organize or facilitate the discussion.
Once the discussion has reached some logical stage, an examination of the energy equation for the biofuel will be done (either small group of individually)
Students can be given data in two areas one is yield per acre and the other is energy per bushel of corn. They would plot these data on a simple graph. Then, using a specific value of based upon the energy output of a bushel of corn converted into ethanol, they would determine the yield necessary to have this project make energy sense.
At this point, historical data on area yields can be provided to compare to the graph and the hypothetical break even point (how many years is production likely to have this project make energy sense).
At this point, additional factors dealing with the concept sketch can be reintroduced, the energy necessary to produce the ethanol from the corn, the amount of water necessary to produce the ethanol.
The end result for the class would be a second vote on the proposal with a reason why.
Assessment: The overall assessment would be based on a) how many students changed their votes and b) how rational the reasons for their votes may change based upon their analysis and discussion.
Data needed: 153 bushels per acre average (USDA) for 2008, historical data for corn production in North dakota, energy, energy conversion values. News articles from 2007 as examples of the news stories and such that involved proposed plants. Grant and subsidy stories would be good too.
(4) Activity: Net energy gain/loss calculations for selected biofuels.
Description: Simple to complex mass balance calculations (using excel) to determine the net energy balance of ethanol or biodeisel using a variety of feedstocks.
- Simple calculation: e.g. 2.7 gallons ethanol from 1 bushel of corn. How much is one gallon of ethanol if you buy corn on the open market? Ignore costs of producing the ethanol. Is this a good deal?
- Increasing complexity: How much does it cost to produce 1 gal of ethanol? Brainstorm with students on what goes into that number (e.g. cost of corn, cost of running the plant, subsidies).
- Simple calculation: How much energy is contained in 1 bushel of corn? Simple calorimetry experiment?
- Simple calculation: How much energy is contained in 1 gallon of ethanol?
- Increasing complexity: How much energy does it take to produce a bushel of corn? Simple question, complex answer. Brainstorm with students (fuel for tractors, fertilizer, etc.)
Now could convert some of this to CO2 and see how CO2 budget works.
Some good refs:
Fargione, et al., 2008, Land Clearing and the Biofuel Carbon Debt, Science 319, p. 1235
Tilman et al, 2008, Carbon-Negative Biofuels from Low-Input High-Diversity Grassland Biomass, Science 314, p. 1598
(6) Potentially Good References
These references are probably a good place to start to find the numbers needed for the above exercise (i.e. the amount of energy per bushel of corn, the amount of carbon per bushel of corn, etc.)
Fargione, J., Hill, J., Tilman, D., Polasky, S., Hawthorne, P., 2008, Land Clearing and the
Biofuel Carbon Debt: Science, v. 319, 1235-1238. (see online supplemental material)
Searchinger, T., Heimlich, Houghton, R.A., Dong, F., Elobeid, A., Fabiosa, J., Tokgoz, S., Hayes, D., and Yu, T-H., 2008, Use of U.S. Croplands for Biofuels Increases Greenhouse Gases Through Emissions from Land-Use Change: Science, v. 319, p. 1238-1240. (see online supplemental material)
Hill, J., Nelson, E., Tilman, D., Polasky, S., and Tiffany, D., 2006, Environmental, economic, and energetic costs and benefits of biodiesel and ethanol biofuels: Proceedings of the National Academy of Sciences, v. 103, vo. 30, p. 11206-11210.