Unit 2: Comparing Energy Choices


At this point in the course, we are going to take a break from thinking about how our patterns of energy utilization are affecting the planet’s climate and think about some more cheerful news – there are plenty of technological options for meeting our planet’s energy needs without the use of fossil fuels. That may seem like a bold statement – after all, our energy systems have been dominated by fossil fuels for a long long time; are currently dominated by fossil fuels; and will likely be dominated by fossil fuels for years to come (until they simply get too expensive relative to other energy sources, perhaps helped along by public policy). Over the next couple of weeks we are going to meet a number of these technologies; learn about how they work, where they are currently being used, and where there is potential to use them even more. Our discussion is not going to focus on whether any particular technology is “good” or “bad” – what you’ll find is that these technologies may be relatively advantageous in some parts of the world and disadvantageous in other parts of the world. We are going to focus on technologies that can be used to generate electricity. Transportation and industry are also important sectors when it comes to energy utilization, but in theory transitioning the electricity sector off of fossil fuels should be a simple first step – after all, there are several thousand power plants in the United States, versus hundreds of millions of cars.

But if we have the technological means to get ourselves off of fossil fuels, then why haven’t we done so already? Is someone keeping a big secret from the rest of us?

As usual, things are not all that simple. As part of our discussions over the next couple of weeks, we’ll learn about some factors that have limited the adoption of specific low-carbon technological options. One of the things that makes comparison of technologies difficult is that there are lots and lots of dimensions to compare across. If cost were the only important factor, then there would be no problem with continuing to use fossil fuels at the rate we are currently. But it isn’t, and even “cost” is not as simple as it sounds.

This second unit covers lessons 6-9. Dr. Seth Blumsack, Associate Professor in the Department of Energy and Mineral Engineering at Penn State, shares his deep knowledge of the many energy options available for our future use. You will learn more about solar, wind, geothermal, hydroelectric and nuclear energy, and about other options including conservation, that together can provide more than enough energy to power humanity sustainably.

  • Solar and Wind (Module 6)
  • Geothermal, Hydroelectric & Nuclear (Module 7)
  • Conservation (Module 8)
  • Geoengineering (Module 9)

Unit Goals

Upon completion of Unit 2 students will be able to:

  • Recognize the great diversity of energy options currently available to us
  • Explain scientific concepts in language non-scientists can understand
  • Find reliable sources of information on the internet
  • Use numerical tools and publicly available scientific data to demonstrate important concepts about the Earth, its climate, and resources

Unit Objectives

In order to reach these goals, the instructors have established the following objectives for student learning. In working through the modules within Unit 2 students will:

  • Recognize the advantages and limitations of solar, wind, geothermal, hydroelectric, and nuclear energy
  • Recall the basic science behind solar, wind, geothermal, hydroelectric, and nuclear power generation
  • Evaluate who is responsible for maintaining "the grid" as home generation grows in popularity
  • Analyze why even people who rely heavily on energy resources tend to want those resources to be exploited far from their own homes
  • Recognize that all energy technologies are inefficient
  • Compare wealth and energy intensity in developed countries
  • Identify options for improving energy efficiency in developed countries
  • Analyze why we don't always conserve as much as we should, despite the double benefits for the climate and our wallets
  • Use a model to calculate the effects of various strategies such as use of renewable energy sources, conservation, and population control on reducing emissions
  • Recall the various geoengineering strategies that have been suggested to mitigate climate change
  • Recognize that geoengineering alone is unlikely to be sufficient to mitigate climate change
  • Assess what you have learned in Unit 2


Assessments and type, by module.
Module Assessment Type
6. Solar and Wind Power Who Pays for Home Generation? Blog: Express Your Opinion
7. Geothermal, Hydroelectric, & Nuclear The NIMBY Syndrome Blog: Find an Article
8. Conservation Emissions Scenarios Stella Model
9. Geoengineering Learning Outcomes Survey Self-Assessment