www.TeachEngineering.org: Free Curriculum for K-12

Contributed by: Integrated Teaching and Learning Program, College of Engineering, University of Colorado at Boulder

Colorado Science
- Standard 5:
  Students know and understand interrelationships among science, technology, and human activity and how they can affect the world. (Grades 0 - 12) [1995]
- 2.2 Students know that energy appears in different forms, and can move (be transferred) and change (be transformed). (Grades 0 - 12) [1995]

Does this curriculum meet my state's standards?

After this activity, students should be able to:

Use a full range of strategies to comprehend technical writing.
Write stories, letters and reports with greater detail and supporting material.
Choose vocabulary and figures of speech that communicate clearly.
Draft, revise, edit and proofread for a legible final copy.
Apply skills in analysis, synthesis, evaluation and explanation to their writing and speaking.
Incorporate source materials into their speaking and writing (for example, interviews, news articles, encyclopedia information).
Write and speak in the content areas using the technical vocabulary of the subject accurately.
Recognize stylistic elements such as voice, tone and style.
Recognize, express and defend a point of view orally in an articulate manner and in writing.
Apply skills in analysis, synthesis, evaluation and explanation to their writing and speaking.

Did you know that a pile of cow manure can be used to generate electricity? Or, a field of corn? Or, sewer sludge? Or, a big heap of rotting bananas? That's right. Australian engineers have developed an electricity generator fueled by decomposing bananas (see BBC News story, Bananas Could Power Aussie Homes, http://news.bbc.co.uk/1/hi/sci/tech/3604666.stm). They plan to build a "full size, fruit-fired power station" to supply the power for as many as 500 homes. This is an example of how biomass — living material that releases methane gas as it decomposes — is used to power an electrical turbine to generate electricity.

You probably already know that high dams such as the Hoover Dam are used to capture the energy of water falling from a great height to generate electricity. This is called high-head hydropower. But did you know that electricity can be generated in a relatively shallow stream, river or tidal basin? That is called low-head hydro and it is more cost-efficient and environmentally friendly than building high dams. In this case, the motion (kinetic energy) of the water turns the electrical turbine. (For more on low-head hydro, see the literacy activity for Energy unit, Lesson 8: A Case of Innovation.)

In the literacy activity for Energy unit, Lesson 7: Windmill of Your Mind: Distributed Energy Goes to School, you learn how a windmill provides the electricity for a school, again by driving an electrical turbine.

Biomass, hydropower and windmills — These are just three sources of alternative energy for generating electricity that you will investigate in this activity. Let's learn about some new ways to cook up electricity!

With the Students

Divide the class into teams of three or four students each.

You are engineers fresh out of college who have just been hired by the alternative energy consulting firm, Greenewables, Inc. You work on a team that specializes in a form of renewable energy used to generate electrical power: passive solar, solar voltaics, wind power, low-impact hydropower, biomass, geothermal and (for more advanced students) hydrogen fuel cells.

Your team will produce a poster demonstrating the benefits of the technology you specialize in and a one- or two-page accompanying summary document in PDF format using Adobe Acrobat software, which incorporates images, graphic elements and appropriate fonts. Or, use a paper template your teacher provides, with a selection of images from which you can choose to cut and paste. Make your best case that your technology will help power the future.

Observing

First, conduct some background reading and research to learn as much as you can about how electricity is generated using alternative fuel sources. The best place to start is the National Renewable Energy Laboratory, http://www.nrel.gov/ and http://www.nrel.gov/clean_energy/student_teacher.html. Also visit the Alternative Energy Institute, http://www.altenergy.org/, and the U.S. Department of Energy's Energy Efficiency and Renewable Energy website at: http://www.eere.energy.gov/ and http://www.eere.energy.gov/education/. TXU Energy's Generating Electricity site, http://www.txucorp.com/responsibility/education/generation/default.aspx, provides clear explanations of how electricity is generated using conventional and alternative sources of energy.

Thinking

Supporters of alternative and renewable energy sources, such as the Union of Concerned Scientists, discuss the hidden environmental and social costs — such as health costs and environmental cleanup costs — of conventional fossil fuel sources of energy, http://www.ucsusa.org/clean_energy/fossil_fuels/the-hidden-cost-of-fossil-fuels.html. These costs are not typically factored into the direct cost of the energy, which to you and your family represents the cost of electricity per kWh.

Renewable energy sources have difficulty competing in the marketplace with conventional sources because they have a higher direct cost to the consumer per kWh. Environmental skeptics challenge supporters of renewable energy sources by saying that the costs of these sources, in terms of maintenance and the inefficiency of operating small plants (called economies of scale) ensure that renewable sources will not be able to compete with conventional, at least not in a timely enough manner to have any impact on global warming or other environmental problems. What do you think? Remember, you are the expert on your Greenewable technology!

Writing

Your written summary should closely parallel your poster presentation, which itself is a summary of your argument for the benefits of your Greenewable technology. Here are a few of the questions to answer:

What is the energy source and how is it used to generate electricity?
What are the requirements and limitations of the source in terms of availability: Proximity to a geothermal source or river, stream or tidal basin? Reliable wind that is strong enough to turn a turbine, but not too strong to damage it? Unobstructed exposure to the sun's rays? And so forth…
What environmental impacts are involved in exploiting the source (impact on fish and other wildlife, for example) and what are the "hidden costs" of minimizing any potential damage?
What are the pros and cons of the source?
How much will electricity cost if it is produced by this source? Can it compete in the marketplace?
Will the source generate enough power reliably to make the local plant able to sell energy back to the grid?
How does this source compare with others in terms of potential to "power the future"?