March 9, 2010
There’s solar, wind and hydro. Nuclear, biomass and geothermal. And don’t forget coal, oil and natural gas.
With so many energy options out there, it’s hard for the normal, bill-paying homeowner or automobile driver or undergraduate to make sense of it all.
But not if Larry Hunter can help it. Hunter, the Stone Professor of Natural Sciences, is teaching for the sixth time a course for non-science majors that explores the physics of energy. Titled Energy, the class doesn’t just go through the H = Cp x m x ΔT of energy, but also the difficult issues surrounding actually implementing so-called “sustainable” systems. “Underlying my desire to simply expose my students to the science of energy are some important secondary goals, such as teaching them to be informed and quantitatively literate citizens,” he explained recently. “I want them to be able to finish the course and make good decisions for themselves and for our environment.”
Hunter doesn’t just lecture about energy. He also practices what he preaches, from bicycling to work to heating his home’s water through solar panels.
Hunter spoke with the Office of Public Affairs’ Caroline Hanna about his approach to teaching the topic, his views on the alternatives to fossil fuels and how his own energy consumption has changed.
|Listen to Larry Hunter discuss his own energy conservation efforts at home by clicking the play button below.
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Tell me about the class.
First, I cover the basic physics of energy—the different forms of energy, how we transform energy from one form into another—and how to think quantitatively about energy. Because I feel that they learn more by doing something rather than by writing down equations and listening to me talk, we do a lot of experiments. It’s mostly hands-on work.
What experiments do you assign?
The first lab I have them do is the least expensive lab I have ever done with students. All it requires is a paint bucket and a $2 thermometer. I ask them to calculate the amount of energy used to heat their shower. Then I ask them to calculate how long they would have to ride an exercise bicycle in order to heat up the water. Typically, you’d have to ride your bicycle about 24 hours a day just to heat your shower. We compare that to how much it would cost to purchase the electricity to heat that hot water. For the “average” shower this turns out to be $0.35, which gives you a sense of what a bargain energy is and why we have gotten so free with using it. When you think about the amount of labor you have to do to get the equivalent of that $0.35 of electricity, it’s pretty daunting.
How do you tackle broader energy issues?
It’s great to say, for example, “There’s an incredible amount of solar energy in the sun and we only need the state of Arizona to power the world.” That is conceptually true, but economically it’s not going to happen because solar power is extremely expensive at this point. I’m also on the energy committee up in Shutesbury, and people in town keep saying, “We’ve got this lake. Can’t we get some energy coming out of the dam off the lake?” By the end of this course, any of my students should be able to calculate on the back of an envelope that, yeah, you can get some energy, but you can only light one lightbulb using that hydro power, versus investing thousands of dollars in equipment. Tapping micro-hydro sounds really good at first, but it takes a lot of kinetic energy create just a little bit of electrical energy.
How have your own attitudes about energy changed since you started teaching this course?
At the beginning, for example, I thought ethanol was a pretty good idea. But after we looked into that during the initial semester, it was apparent the whole thing was a boondoggle. First of all, it’s not clear that you burn any less non-renewable fuel, especially when you’re using corn. Corn is such an energy-intensive crop that the amount of energy that goes into growing corn is at least comparable to or even more than the amount of energy we get out of the ethanol. And the environmental consequences are horrible. It’s a very expensive way to make energy from food. Plus, you don’t really want people to starve because we’ve turned their food into fuel.
Right now my belief is that our current use of energy is in transition, so we talk a lot about that idea. Why is it in transition? Well, regardless of what you believe about climate change, it’s pretty indisputable that we’ve used roughly half the oil available on the planet and the oil we’ve used is the ‘easy’ half—meaning, what’s left is getting harder to extract. There’s going to be increasing demand for oil in China and India, where the rate of use of the automobile is going up exponentially. The cost of extracting the more difficult oil—the deeper oil—is high, both economically and environmentally. The supply of oil cannot continue to rise and at some point, basic economics will kick in and prices will start rising. So we talk about alternatives to oil: nuclear, solar, hydro, fossil fuels, geothermal/geoelectrical. We survey what’s out there and try to get a sense as to the real costs of these things.
I think when one looks at the real costs of energy production, conservation begins to look very attractive. By being smart about how we use energy we can reduce our consumption and environmental impact without a significant decrease in quality of life. With some simple changes at home, for example, my family and I have reduced our home electric bills a factor of five and our gasoline consumption by nearly a factor of two.
Hunter’s own home energy installation.
Do you keep up on the current discussions about energy even when you’re not involved with the course?
Yes, but I’m much better about it when I’m offering the class. Every meeting begins with a scan of what’s new in energy. Much of our discussion of alternative energy sources is also informed by having experts come in to speak. The combination of the news items and the guest lecturers keeps the course fresh. Every year the emphasis is a little different.
I see you’ve got a battery under your desk right now.
This battery is being charged by the sun. About 2.8 amps are flowing down to it from a solar panel on the roof. There are five panels on top of Merrill [Science Center]. Four of them are connected into the building via an inverter, which provides Merrill with a little bit of energy. It’s a pathetic amount compared to the total consumption of the building—probably enough to keep my office lit. Some students created an interface that allows us to monitor the energy production. The data is also posted on the web, so you can log in anytime and see how much energy they’re producing. Some energy equivalencies are also on the webpage. We compare, for example, our energy production to the energy consumed in Merrill, the energy consumed by an average person in Chad, the energy consumed in heating a shower and the energy consumed in running a lightbulb.
Anyway, the battery under my desk is charged by one solar panel and the wind turbine on top of Merrill. By connecting the battery to an inverter I can use this battery to run my computer or the projector I use in class. If I bring the battery to class, I always make a point of telling the students that we’re using wind or solar energy for that day. As we speak, my computer is being powered by the sun.