How to Throw Away Old Stuff, Without the Guilt

A new study sees energy savings in buying instead of fixing

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Steven Cherry: Hi, this is Steven Cherry for IEEE Spectrum’s “Techwise Conversations.”

We’ve all had the guilty experience of throwing something away instead of getting it fixed. I asked a colleague of mine, and she instantly came up with four: a couch, a toaster, an iron, and a clothes dryer. According to a new study by researchers at MIT, she needn’t feel so guilty. In fact, she ought to feel less than half as guilty as she does.

The researchers studied the energy cost of repairing or remaking—or remanufacturing, as the study calls it—versus the energy cost of a new product, for a number of products in eight different categories. In some cases it was too close a call to say one was better than the other, and in the remaining cases, for about half of them it was better to get a new one.

But doesn’t it almost always take much more energy to make something from scratch? Of course it does, and the study confirmed that. But the MIT researchers also did a life-cycle analysis of the products they looked at. And when they did, often the new version not only did better, it did so much better that it made up for the initial manufacturing overhead.

For example, they looked at automobile tires. Retreads—putting new rubber on a worn tire—takes a whole lot less energy. But it also turns out they’re not quite as good as new tires, so your mileage is a little less. And when you add that up for the thousands of miles you’ll put on them, the energy balance tips to the side of the new tire.

My guest today is Timothy Gutowski. He’s a professor of mechanical engineering at MIT and one of the four coauthors of the study, which was published in the journal Environmental Science & Technology. He joins me by phone. Tim, welcome to the podcast.

Timothy Gutowski: Thank you, Steven. I’m happy to be here.

Steven Cherry: Tim, looking at that four list of items: Couches don’t get a lot less efficient when you remanufacture them, so I guess the repair wins there. What about the other three—the toaster, the iron, and the clothes dryer?

Timothy Gutowski: Well, it depends on what’s going on with the new products. First of all, we don’t advocate throwing them away in any case. There are other alternatives to remanufacturing or extending the life of the product. For example, you can capture the materials in the product and recycle those and use those again, and that saves energy. But our study focused on those collection of activities we used the term remanufacturing, but in the details of the study, we extended it to refurbishing, reselling, reusing, all of those kinds of things you can do with a product to keep it around longer and get a more useful life out of it. With the other ones, it depends on two things, basically: what’s happening with toasters or the other products in terms of the new ones, or does the remanufacturing or the refurbishing of the product in some way degrade the energy consumed by it during the lifetime.

Steven Cherry: Yeah, so that clothes dryer has a motor, and I guess you found something in particular with respect to electric motors.

Timothy Gutowski: Well, electric motors are pretty efficient—they’re not 100 percent efficient, so they can improve—but what we found was that in the case of electric motors, the rewinding—which was the main activity in the remanufacturing—can result in degrading the energy performance slightly of the remanufactured motor. In fact, even DOE [Department of Energy] in their guidelines for doing cost calculations makes the recommendation that for the smaller motors on the order of 22 kilowatts, something like that, you degrade the performance by about .5 percent of the energy performance. And for the larger ones, say, around 220 kilowatts, you degrade it by 1 percent. Now, that small difference and the low cost of energy still often results in the remanufactured motor being a good deal financially, but from an energy point of view, it may tip the balance in the other way. I think for the electric motors we looked at, generally, it made it slightly more energy consuming than buying a new product.

Steven Cherry: Yeah. So there’s one complication here—well, actually there’s probably several: The decision to remanufacture or buy a remanufactured article isn’t just driven by the energy cost, right? I mean, people take into account the dollars cost and especially the immediate cost, you know, like that clothes dryer—a new one might even make sense in the long run, but I might not have the cash to pull off a new purchase.

Timothy Gutowski: Well, absolutely. In fact, people don’t consider energy at all ,probably. I mean, if you were considering energy, you wouldn’t use the clothes dryer in the first place; you’d hang your clothes outside. So energy just doesn’t show up in a lot of these calculations. And we appreciate that, we know that—I mean, I have a clothes dryer in my house, and I have many of these same items, you know, we talked about in our paper, so I understand that the consumer or the purchaser or whoever they may be makes the decision for a variety of different reasons: cost, convenience, good feeling about the environment, whatever. But we just wanted to look at, you know, if energy was the most important thing, what’s going on here? And we were surprised because remanufacturing, you know, has a special part in all environmentalists’ hearts. If you ask a group of people, what’s the best thing to do with a product at the end of life, raise your hand, and you go through the different options—remanufacturing, recycling, incineration, landfill—generally, you’ll find everyone voting for remanufacturing. But it turns out that that’s not always the case. And again, the two overwhelming reasons are that either the remanufactured product is degraded slightly in its performance, or the new products are being improved, and the new one will consume a lot less energy over its lifetime. If you just go next to your clothes dryer and look at your clothes washer, for example, the changeover in technology from the top loader to the front loader makes buying—if you’re thinking about extending the life of a top loader, then you look at the energy consumed by a front loader. From an energy point of view, the better choice is to buy the front-loading clothes washer.

Steven Cherry: So these life-cycle analyses sound pretty complicated. I mean, do you take into account things like landfill and the fact that a repair might involve taking something down the road, whereas a new clothes dryer might come all the way from China and so forth?

Timothy Gutowski: Well, we do. We did include transportation, and there is a transportation difference. That’s exactly right; remanufacturing is often a much more local activity, and it’s a more labor-intensive activity, so there were cases where the transportation was very important. You could, for example, refurbish a laptop computer, upgrade it, add memory, add features, and so forth, and that will save not only the making of the new computer but also the transportation. A lot of our computers now come from China or Asia, and often they’re air freighted here, so the energy and carbon associated with that transportation is significant.

Steven Cherry: So you said before that consumers pretty much don’t take energy by itself into account at all in these decisions. I guess one of the things about your study is it might motivate us to take them into account at least a little bit. You know, if these life-cycle analyses are so complicated, how would a consumer do that?

Timothy Gutowski: You know, that’s a good question. [laughs] I don’t know. Certainly, what we found in our case was that we had all kinds of answers, and that it depended on the details, and it depended on how the game was changing, how efficiency was improving for devices; sometimes that was mandated by regulations, often it was due to new technology changes, going from IS ply tires to radial tires, and so forth. So I don’t have a simple answer for that. Certainly, people are laboring in that direction, labeling products; you’ve got Energy Star and so forth, and that’s a pretty good guide, but you may have trouble when you’re looking at an old product and you’re comparing it to a new one. I don’t know of a comprehensive system that allows you to do that easily.

Steven Cherry: So I guess one result from your study is that it might be of help to regulators. You know, I noticed that in your work that you’re also trying to help manufacturers make rational decisions, and along those lines you’ve been studying something you call material efficiency. Tell us what that is.

Timothy Gutowski: Well, I’m working with a couple of other colleagues, looking sort of specifically at the energy use, CO2 emissions, and the other collections of environmental effects associated with materials and trying to think about how we could reduce our impacts as associated with material use. And material efficiency is sort of one part of that, that focuses on strategies to get more services out of material but maybe use less. So some of it might seem to be things like downsizing, going to smaller and smaller devices, getting the same service for less material. But at the same time we’re very much aware of the larger kind of things going on; sometimes when you make things small and convenient, then people just buy two. And so often our efforts at the engineering level are somewhat offset—or at least our hopes, our aspirations, our efficiency aspirations, at the engineering level are somewhat offset by the consumer behavior and how they buy and use their products.

Steven Cherry: This is the kind of research that consumers can really benefit from in the long run, whether it comes by way of regulation or in some other way, and manufacturers themselves would benefit. It’s the kind of research that nobody is really willing to pay for, so I think on behalf of everybody, I need to thank you for doing it.

Timothy Gutowski: You’re welcome.

Steven Cherry: We’ve been speaking with MIT professor of mechanical engineering Timothy Gutowski about the surprising fact that it often makes sense to buy something new rather than remanufacture it. For IEEE Spectrum’s “Techwise Conversations,” I’m Steven Cherry.

This interview was recorded 24 May 2011.
Audio engineer: Francesco Ferorelli
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