Measuring The Carbon Footprint Of A Charcoal Grill

Researcher Eric Johnson recently revealed that charcoal grills leave a much larger carbon footprint than their gas-powered counterparts. On what may be the busiest grilling day of the year, Guy Raz speaks with Johnson about his study.

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GUY RAZ, host:

Now, if you're looking for a chance to help the planet this Fourth of July, why not start in your own backyard? Have you ever considered the carbon footprint of your outdoor grill?

Eric Johnson runs a scientific research firm in Switzerland and he studied the environmental impact of both gas and charcoal grills. And it turns out that gas grills aren't just better for the environment, they're much better.

Mr. ERIC JOHNSON (Director, Atlantic Consulting): The carbon footprint of a gas grill is about one-third the footprint of a charcoal grill. I mean...

RAZ: Wow.

Mr. JOHNSON: ...and most of that footprint is from the fuels being burnt.

RAZ: And that includes the process of manufacturing and other things, like the transportation of the fuel.

Mr. JOHNSON: That's right, transport, the whole thing. But what you find is that far and away, the major impact comes from the actual production and burning of the fuel itself.

RAZ: The smoke.

Mr. JOHNSON: Yes. Yes. I mean, in the case of charcoal briquettes, the key to it is the efficiency with which they work. They're a pretty inefficient way to cook things. I mean, you know, you shake the bag out. You put it all over the grill. You burn up this whole grill and maybe you're cooking a couple of burgers.

Whereas gas-fired grills are similar to the stove you use in your kitchen. It's much more attuned to how much you're actually going to cook, how much energy you really need to use.

RAZ: You know, some people might be surprised to learn that, you know, using charcoal is worse for the environment because essentially, it's a biofuel. Right? I mean, it's a natural product.

Mr. JOHNSON: That's right, it is a natural product. But generally, it is harvested in order to be used. And so you're removing carbon from the biosphere and putting it up in the air.

RAZ: Well, how does that work?

Mr. JOHNSON: Basically, what happens is that people take cut wood or even wood waste, but generally, its actually harvested cut wood. And they stick it in a kiln with a limited supply of oxygen so that the wood doesn't actually burn. And what happens is most of the liquid parts of the wood are flashed off and you're left with almost pure carbon.

I mean, if you look at gas, you know, something like 90 percent of the heating value that came out of the ground actually gets used in the grill. I mean, in charcoal, it's less than one-quarter. It's just much, much more efficient.

RAZ: You actually spend time grilling yourself, right?

(Soundbite of laughter)

Mr. JOHNSON: Yes, I did. I think there were eight - seven or eight other volunteers. I can't remember exactly. But we split into one group that did gas grills and one did charcoal grills. And it was kind of an amusing experience for families and friends, because they were watching us measure everything out as we did it, measure afterwards and all that sort of thing.

But I think we ended up with something like 50 or 60 grill sessions at the end, which provided us a pretty good statistical basis in order to, you know, make all these measurements and come up with the footprints.

RAZ: And presumably, provided you with a lot of meat.

(Soundbite of laughter)

Mr. JOHNSON: Well, not everybody was cooking meat all the time. But yeah, I mean - and we did actually note all the different things that were cooked. So it was kind of a - I mean, people were chuckling at us a lot. But it did work.

RAZ: Mr. Johnson, there's a good chance that somebody listening to this interview right now is actually outside grilling. And if they're grilling over, you know, charcoal briquettes, what would you say to them?

(Soundbite of laughter)

Mr. JOHNSON: What I would say is that it's not like we're going to kill the planet in the grilling scenario. But probably, the most helpful thing you could do is when you're done, if you could shutdown your grill and try to reuse what coals are there. Now, some grills are actually relatively easy to shutdown but a lot of them are quite difficult. But still, you know, pour some water on it and use them again, because you're really wasting it when the rest of it just goes up in the air.

RAZ: That's great advice.

Eric Johnson is a chemist and the director of Atlantic Consulting in Zurich, Switzerland. His study into the carbon footprints of both charcoal and gas grills can be found on the Web site sciencedirect.com.

Mr. Johnson, thanks so much.

Mr. JOHNSON: Thanks for having me.

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