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  Sierra Magazine
  November/December 2007
Table of Contents
Go Big Green
10 That Get It
Talk of the Quad
Hot Jobs for a Warming Planet
City Kids Unplugged
Editor's Note
Ways & Means
One Small Step
Lay of the Land
Good Going
The Green Life
Hey Mr. Green
Sierra Club Bulletin
Sierra Archives
About Sierra
Internships at Sierra
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hey mr. green
Mr. Green's November 1, 2007, Mailbag

Rants, raves, and righteous ideas from our readers

Mr. Green loves hearing from his readers, whether they think he's a green guru or an eco-idiot. Periodically, he'll post some of his favorite exchanges online. To join an ongoing debate—or start a new one—e-mail

Prius Versus Hummer: A Nickel for Your Thoughts

Hey Mr. Green,
I am looking to replace my 11-year-old commuter car with a new one and was thinking about getting a hybrid. But I have heard that the energy used just to produce the battery in a hybrid is more than a Hummer uses over its lifetime. Now I'm wondering if I would be better off getting a really fuel-efficient regular car.

My other concern is that the battery in a hybrid may not last for the life of the car. As you can see, I prefer to keep my cars for at least ten years. Will a hybrid battery work that long?

Please help! I want to do what's best for the environment, so I'd appreciate it if you could clarify this matter for me. —Jennifer in Downingtown, Pennsylvania

Hey Jennifer,
Some wonderful urban legends have sprung up about the Prius and its battery, the most colorful being this claim about the hybrid being less ecofriendly than a Hummer. Some of the more thrilling chapters originated in one study done by a marketing company that was not peer-reviewed but, unfortunately, was widely quoted in the media. Writer George Will, who is syndicated in 450 papers, penned an April column on the topic, headlined "Use a Hummer to Crush a Prius." The story was also pumped into the Internet-disinformation pipeline by gleeful bullies for whom size is apparently quite important, and before long the Prius had morphed into a sort of traveling toxic-waste dump trailing clouds of diabolical fossil-fuel exhaust.

You can disprove most of the false claims by doing a bit of math. Regarding the hybrid battery, let's say a Hummer is driven 200,000 miles in its lifetime. Its EPA rating is 14 miles per gallon in the city and 18 miles per gallon on the highway. Let's be real generous and assume it is driven only on the highway at a reasonable speed, yielding the maximum mileage. Divide 200,000 by 18, and you're talking 11,111 gallons of gas.

Next let's calculate the Btus in that amount of gasoline and convert them to kilowatt-hours. Gasoline has between 115,000 and 125,000 Btus per gallon, so the Hummer would burn through about 1.3 billion Btus over those 200,000 miles. Since there are 3,412 Btus in a kilowatt-hour (kWh) of energy, this would convert to almost 400,000 kilowatt-hours, which, at the rock-bottom price of five cents per kilowatt-hour, would be about $20,000, or almost as much as the price of a Prius. If the energy to make the hybrid battery came from fuel oil, which has around 140,000 Btus per gallon, it would take an estimated 9,524 gallons of oil to match the Hummer's 1.3 billion Btus. At $2 a gallon, that's also about $20,000.

Now if Toyota is truly spending that much money on the battery alone, U.S. automakers can stop worrying about the Japanese competition pronto. Either that, or Toyota is cooking up the most brilliant marketing strategy in the history of modern capitalism: investing unprecedented prodigious funds in a loss leader!

In any case, the study indicting the Prius has been discredited by a number of reliable sources since its appearance early this year. As David Friedman, the research director of the Union of Concerned Scientists' Clean Vehicles program, put it: "This study has been completely contradicted by studies from MIT, Argonne National Laboratory, and Carnegie Mellon's Lifecycle Assessment Group. The reality is hybrids can significantly cut global-warming pollution, reduce energy use, and save drivers thousands at the pump."

Among the many critics of Hummer hugging, Peter Gleick of the Pacific Institute noted that one of the many flaws of the CNW Marketing study is that it is based on fudged figures. As he points out, it assumes a Hummer would travel 379,000 miles in its lifetime and last 35 years, whereas a Prius would only go 109,000 miles and last 12 years. So of course, using these figures, the amount of energy needed to make the Prius is going to come out high on a per-mile basis. (Who knows? In real-world time the Hummer might well have a shorter life because when the owners get bored with their mega-toys and want to dump them, no one may want to buy these gas hogs. Note also that I could've fudged and used that 379,000-mile figure, which would've jacked up the Hummer's lifetime energy use for fuel alone to a value of around $37,000.)

Getting back to the Prius's nickel metal hydride battery, laments about its other environmental iniquities were largely based on reports of environmental devastation from nickel mining in Sudbury, Ontario, where 10 percent of the world's nickel is mined. The problem is that these reports described Sudbury 30 years ago, not today. Yes, nickel mining is a nasty business, but in the 1970s, Sudburians started to clean up the mining mess and make huge strides in rehabilitating their environment. As Canadian Geographic declared recently in giving one Sudbury group an award for restoration, "Once derided for its barren landscape, Sudbury, Ontario, has experienced an environmental makeover since the 1970s. Today, the former industry-blighted moonscape has been transformed."

In any case, Prius batteries, which contain 32 pounds of nickel each, require only a fraction of the world's supply. More than 94 percent of the 1.55 million tons of nickel mined each year is used for stainless steel, alloys, and electroplating. So the batteries for the one million hybrids Toyota has sold so far have required only one percent of the world's annual nickel-mining production. Since the estimates on nickel recycling indicate about 80 percent is being reused, a million Priuses' share of newly mined nickel would really only be about two-tenths of one percent.

Additionally, Toyota researchers say that a Prius battery will last for at least 180,000 miles. There's no reason to believe that the company is inflating its figures, for the simple reason that Toyota issues an eight-year or 100,000-mile warranty on their batteries. Company representatives say that very few batteries have failed and that some fleet cars have already racked up 200,000 miles and the batteries are still going strong. The Prius batteries are also completely recyclable, and Toyota's recycling program even issues a $150 credit when they're finally retired.

Finally, after much Hummering and hawing, there remains your question whether you'd be better off getting a "really fuel-efficient regular car." Well, you might. As previously reported here, I've driven another Toyota, the Corolla, and gotten 42 miles per gallon, a mile more than its official EPA rating. That's pretty competitive with the Prius, especially when you consider that the Corolla costs about $7,000 less. So that regular car may be a sensible alternative to the Prius, but not because the Prius is environmentally worse than the Hummer.

Mr. Green

Overflowing With Water Tidbits

Mr. Green's November/December print column about bottled versus tap water barely skimmed the, um, surface of this complex topic. Though he noted that tap water is not tested as often for lead, it's worth adding that health risks can be minimized by using only cold water for cooking or drinking—and letting it run for a while first. And while Mr. Green briefly alluded to the dangers of well water, which has a greater likelihood of containing arsenic and contaminants from agricultural chemicals, he'd also like to share this link to the Centers for Disease Control and Prevention's recommendation of testing all well water. Water conservation is a topic for another day, but those interested might enjoy a short interview in the same Sierra issue with the cofounder of the Greywater Guerrillas, a group that helps people install their own systems for reusing sink water on their yards.

Perverts, Public Safety, and the Planet

Hey Mr. Green,
In your answer to Sue regarding the school bus situation, you stated that "if I were running the district with my green iron fist, I'd require all those lazy, pampered kids to walk or bike to school, like in the old days." It's a nice sentiment but not practical in today's world. There are too many child predators waiting for this opportunity. In my neighborhood alone, there were three known attempts of men trying to lure or drag children into their cars just this past year. Each child was either walking alone or with a friend home from school or, in one instance, playing in front of her own house. Although I wish we lived in a world where kids could walk or bike to and from school without the threat of being accosted, I would not feel comfortable letting my child do this. For exercise, children should try sports or dance in a safe environment. —Tamara in Flushing, New York

Hey Mr. Green,
Just a comment regarding your advice that children should walk to school. Rather than excoriating these "lazy" kids, let's remember the hazards they face in many suburbs—lack of sidewalks, lack of pedestrian crossings, and excessive traffic with its attendant lack of controls. These deficiencies would put too many kids at risk of serious injury or death, especially given the impulsiveness of youths. Let's get our local governments to supply the needed upgrades so that kids can walk or bike again, safely. —Joan in Fairfax, Virginia

Hey Tamara and Joan,
I'm becoming such a crusty geezer that I need to hear such objections. Even granting my opinion that kids today are lazy and overprotected, you're right: The streets should be made tolerably safe for them—and for us grown-ups. Many adults would gladly ride bicycles, but they're scared stiff by traffic, and I don't blame them. I personally know a half dozen people who have been very seriously injured because they were hit by a vehicle or mugger while riding. I recently met a young woman who will not use a bike any longer because she was "doored" by someone getting out of a car. Though I've been doored too, I certainly don't expect everybody to hop back on a bike after such a harrowing episode.

But fear begets fear. The fact that so few people are out on the sidewalks and streets in the first place encourages predators and lets dangerous drivers rip along without being detected. So it becomes a classic catch-22: We keep our kids and ourselves off the streets because we're scared, and then the streets become scarier because nobody's on them. We burn billions of gallons of extra gas inside our vehicular fortresses while the pervs patrol.

A partial solution would be to limit traffic and create truly safe bike lanes and walking paths. I've seen this work in some cities in Europe, where you'll find old guys pedaling bikes while holding their canes over the handlebars, old women tooling about with basketfuls of cargo, and the younger set rolling along while talking on their cell phones. So if you're looking for a worthy way to restore a measure of civilization to our car-menaced world, this might be the campaign to take on.

Mr. Green

Views expressed by readers may not reflect those of Mr. Green or Sierra magazine. Reader suggestions have not been researched or tested.

Read more advice from Mr. Green, including his Web-only mailbag, and submit your own environmental questions at

Mr. Green illustration by Melinda Beck; used with permission.

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