Segment 9

Just how much energy can Sun, hydropower, biomass and geothermal offer? This segment sets a target of seeing whether, in principle, renewable energy resources could meet today’s global energy needs of about 15.7 terawatts, described by Richard and illustrated on camera as the equivalent of 157 billion 100 watt light bulbs. Starting in the deserts of America’s Southwest, one of the sunniest places in the world, we travel to Spain, Brazil and New Zealand putting numbers on the potential of some of the most promising, non-CO2 emitting renewables: solar, hydro-power, biomass and geothermal.
The pros and cons of each energy source are cited, and the Annotated Script provides several links to find out more. Richard points out that today’s technologies have begun the long process of harvesting this vast renewable potential in ways that are already—or soon will be—economical and technologically adequate. Looking at a giant Concentrated Solar Thermal plant in Spain, soon able to supply the entire power needs of the nearby city of Seville, and the long transmission lines taking power from the huge Itaipu Dam to one of Brazil’s largest cities, he says we’ve already made a start.

Annotated Script
Please refer to pages 98-115

• Students will be able to list in order of potential contribution to meeting Earth’s energy needs the following renewable resources: the Sun, hydropower, biomass and geothermal. (This is one of the Quiz questions in Sustainable Energy and perhaps could be a discussion starter.)
• Students will be able to cite the pros and cons of biomass used for fuel, and compare and contrast corn and sugar cane as feedstocks for biofuels. (Use of the Annotated Script required to read source documents.)
• Students will understand that different nations and different regions are able to use different renewable energy resources.

Energy, watt, kilowatt, kilowatt hour, megawatt, terawatt

If students have not previously done the Sustainable Energy Quiz (on this website) and if you have sufficient web access, consider asking students to rate the relative potential contribution of the various renewable energy options. Ask them, depending on where your school is situated, which renewable option they think might be most practical and useful to their region.

Then show the video segment, and implement one or more of the following activities.


1) CONCEPT: There are more than enough feasible technological approaches to meet global energy demand with sustainable energy resources. Selecting several options (or wedges) from the available menu can meet that goal.


Original activity:
Carbon Mitigation Initiative, Princeton University

The CMI team writes, “The Stabilization Wedges Game is a team-based exercise that teaches players about the scale of the greenhouse gas problem, plus technologies that already exist to dramatically reduce our carbon emissions and get us off the path toward dramatic and damaging climate change. Players pick eight carbon-cutting strategies to construct a carbon mitigation portfolio, filling in the eight wedges of the stabilization triangle. The game has been used with players from variety of groups, from university researchers to industry professionals to high school students, and we'd like to help you play with your class or organization.”

As Richard says in the book and broadcast, there are many plans that can meet global energy demands while substantially reducing the use of carbon-emitting fossil fuels. This game, from the same team of Princeton researchers (Sokolow and Pacala) whom Richard describes in the book on pages 220-221, provides an accessible entry-point to otherwise complex economics and technology. Note, as above, that it’s upper middle, or high school level in content and approach.


2) CONCEPT: Addressing the energy challenge involves not just confronting supply, but also demand. Giving students an appreciation of energy used in daily life is a useful first step.


Original activity:
Marie Johnson, SERC, On the Cutting Edge Collection

This is an idea for a one-period classroom activity designed to have students analyze energy use, cost, and source patterns from household to regional scales, and relate these patterns to CO2 emissions.

The CLEAN team provide the following suggestions: “Carefully analyze the worksheet to make sure it is appropriate for your students—modify as appropriate. The worksheet will likely need scaffolding for younger students and higher level questions for older students. Younger students may require pre-teaching to calculate the percentages of CO2 emission. This activity could be used as an introduction to the Lifestyle Project


3) CONCEPT: “Bottom line, there are many ways forward, and we can hit that renewable energy target.” Richard Alley in the ETOM broadcast.


The NREL education website has a wind range of activities, from Elementary through High School, focusing on solar, biomass, wind, efficiency (also please see video 10 and associated content.)

Perhaps, if time permits, it would be good to try to work in more than one renewable option, to re-emphasize the point made in the previous Wedges activity: there’s more than one way forward, and it’s almost certainly going to take an evolving mix of energy resources.

This video clip is full of facts: New Zealand gets 10% of its electricity from geothermal, and Brazil 80% from hydropower. Either from watching the video, or from independent research, have students work in teams to develop their own Sustainable Energy Quiz, expanding on the one found on the ETOM website. If computer science/technology is part of your mandate, have them prepare a Powerpoint or Keynote presentation as part of a classroom exercise, and see how their peers do on this “test.” Extending school to home, have students select five or more of the new class-generated questions to ask parents or caregivers, and invite reports on a student-parent KWL experience!

ET Core Idea 2:
Engineering design is a creative and interactive process for identifying and solving problems in the face of various constraints.
Why are technologies created?
How do technologies interact with society?
What kinds of knowledge are needed to solve different technological problems?
How can people work together to develop a variety of solutions then mold these ideas into a single workable solution?
How can the best possible design be determined?

ET Core Idea 3:
People are surrounded and supported by technological systems. Effectively using and improving these systems is essential to long-term survival and prosperity.
How do systems relate to larger and smaller systems?

ET Core Idea 4:
In today’s modern world everyone makes technological decisions that affect or are affected by technology on a daily basis.
Consequently, it is essential for all citizens to understand the risks and responsibilities that accompany such decisions.
Why do technologies vary from one locale to another?
How might the environment be affected when making tradeoffs during the making of new technologies?



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