Wheels: Revisiting Diesel

Why the oft-maligned fuel of the 70's is greener than ever before

By Frances Cerra Whittelsey

ON A RECENT DRIVE FROM NEW YORK TO FLORIDA, zipping along Interstate 95 at 80 miles per hour with the rest of the traffic, my car burned fuel at the efficient rate of 40 miles per gallon. My car is not a hybrid. It’s a diesel, a 2002 Volkswagen TDI Jetta that in a gasoline version consumes at least 25 percent more fuel.

The fact that diesels get such good mileage is something of a secret in the U.S. Diesel cars are a rarity here—they make up less than 1 percent of cars on the road—in part because consumers are wary of them. The average person’s mental image of a diesel vehicle is a noisy bus or truck spewing smoky, smelly exhaust fumes. Moreover, in the late 1990s, diesels got caught up in California’s fight against smog. Diesel engines emit higher amounts of nitrous oxide, a major component of ground smog and of tiny particles that play a role in causing lung cancer and asthma in urban areas such as smoggy Southern California. Even though diesel trucks and buses are almost solely to blame for the problem, California requires new diesel cars to meet the same air-quality standards as gas cars, and that brought sales of new diesels there to a halt. Other states, including my home state of New York, have followed California’s lead, thus effectively shutting off about 25 percent of the U.S. car market to new diesels.

These air-quality issues have also stopped environmental organizations from recommending diesels. While the Sierra Club, for example, gives the highest priority to improving mileage per gallon as a way to cut our dependence on oil and emissions of greenhouse gases, it advocates hybrids, not diesels, as the best way to achieve that goal.

But as I discovered in the process of buying my Jetta, new technology has already quieted diesel cars and cleaned up the visible smoke, and updated diesel cars that meet the California standards will probably be introduced within a year. What’s more, three diesel cars made the Environmental Protection Agency and the Department of Energy’s list of the 10 most fuel-efficient models this year. Diesel vehicles, in fact, get between 20 percent and 40 percent better mileage than comparable gasoline cars, and therefore contribute less carbon dioxide—the principal greenhouse gas—to the atmosphere.

Moreover, cleaner commercial diesel fuel is becoming available; the oil industry has made a commitment to remove nearly all of the sulfur from diesel fuel sold in the U.S. by this fall. And diesel engines, which use pressure rather than spark plugs to ignite the fuel, have always been able to run on cleaner-burning vegetable oil and even animal fat (which means you can make your own diesel out of waste grease from restaurants). More than ever before, diesels are a thrifty and green alternative for drivers who want to fight global warming, reduce oil consumption, and still have fun driving.

Those were my motivations when I set out to buy a new car in late 2004, but at the time I wasn’t even considering a diesel. I intended to buy a hybrid. I was dismayed, however, to learn that the wait for a Toyota Prius was about a year. At a Honda dealer, I looked inside the trunk of the Civic and saw that much of it was occupied by the hybrid’s battery. No room for my golf clubs and cart? No sale. I always carry my clubs with me—you never know when you can squeeze in nine holes.

I was stymied until I remembered hearing that a nephew of mine was a big fan of diesels. The models I test-drove had great pickup—a pleasant surprise. Their inherently more powerful design makes it possible for tiny engines like the 1.9-liter motor in my Jetta to deliver the acceleration of a much bigger gas engine. Diesels also appealed to my thrifty nature. While they cost more—typically between $300 and $2,000 more than comparable gasoline-powered cars—diesel engines usually last for hundreds of thousands of miles and retain much more of their value as they age.

I also thought I’d be getting a bargain at the pump because, historically, diesel fuel has always been cheaper than regular gasoline; as recently as the summer of 2003, it cost about five to seven cents per gallon less. But that changed with the hurricanes of 2004 that disrupted production and with growing worldwide demand for diesel fuel, particularly in China and Europe. Now diesel costs more than premium, from a few cents to as much as 30 cents or more a gallon.

Nevertheless, a gallon of diesel goes a lot further than a gallon of gas, and it seemed to me that if Americans were driving more diesels, we would be importing a lot less petroleum. That’s been Europe’s strategy. There, about 40 percent of the vehicles on the road are diesels, including dozens of makes and models that aren’t even sold in North America, like the BMW 5 Series Saloon, which gets 50 miles to the gallon. In our part of the world, the only new diesel choices (besides pickups) are several Volkswagen models, the Mercedes Benz E320 CDI, and the Jeep Liberty diesel; and in Canada, the Mercedes Smart Car for Two. A Mercedes C-class sedan and an Audi diesel SUV are expected to be introduced this fall.

But even more models may arrive soon as manufacturers overcome the challenge of California’s clean-air rules. The low-sulfur petroleum diesel coming this fall will make it possible for manufacturers to fit diesels with particle filters and catalytic converters to remove the unhealthy pollutants. Fuel with sulfur clogs the filters and converters so quickly that they become worthless. In fact, Daimler-Chrysler announced in January that its newest diesel technology, to be used in the 2007 Mercedes E320, will comply with California’s regulations, as well as new federal emission standards for the whole country that will begin to be phased in next year.

So today’s diesels are not a perfect choice. Still, the used Jetta diesel that I ended up buying met my needs for fuel efficiency and roominess. (Used diesels can be sold in all states thanks to free-market rules established years ago.) I’m not willing to make my own fuel from waste grease, but a pump supplying biodiesel (commercial-grade vegetablebased fuel) is supposed to open soon not far from me. Elsewhere, particularly in the Midwest, biodiesel is much easier to find, generally blended in with some percentage of petroleum diesel.

I love the idea of a future in which we can turn away from petroleum, growing fields of soybeans or sunflowers or tanks of green algae that can be processed for oil to fuel our vehicles. Almost 100 years ago, Dr. Rudolf Diesel, who invented the engine that bears his name, recognized that the ability to run diesels on vegetable oil could mean energy freedom. He foresaw that no one anywhere in the world would have to be dependent on foreign petroleum. My car is my way of trying to make his vision come true.

2006’s Most Fuel-Efficient Cars

When buying any car, keep in mind that real-life mileage can be considerably less than sticker estimates. The Toyota Prius, for example, got a combined 43 miles per gallon driving around a hilly, suburban community and on the highway. My Jetta diesel averages about 31 miles per gallon under the same conditions. Diesels are most efficient for highway driving, whereas hybrids are better for city conditions with stop-and-start traffic. Hybrid batteries reduce cargo space, something to keep in mind if you have children or take lots of road trips. Hybrids also cost about $3,500 more, on average, than their gasoline counterparts, but tax credits can help close the gap. You’ll pay between $300 and $2,000 more for a diesel vehicle.

Model/city/hwy/Sticker Price
1. Honda Insight Hybrid, 2-seater, manual - 60/66 $19,330

2. Toyota Prius Hybrid - 60/51 - $21,725

3. Honda Civic Hybrid, automatic - 49/51 - $21, 850

4. Volkswagen New Beetle, manual, diesel - 37/44 - $18,390
VW Golf, manual, diesel - 37/44 - $19,580

5. VW Jetta, manual, diesel - 36/41 - $21,605

6. Ford Escape Hybrid SUV - 36/31 - $26,980
front wheel drive, automatic

7. VW Jetta, Diesel, automatic - 35/42 - $22,680
VW New Beetle, automatic, diesel - 35/42 - $19,465

8. VW Golf, automatic, diesel - 33/44 - $20,655

9. Ford Escape Hybrid SUV, 4WD - 33/29 - $28,525
Mazda Tribute Hybrid SUV, 4WD - 33/29 - NA*
Mercury Mariner Hybrid SUV, 4WD - 33/29 - $29,225

10. Lexus RX400h Hybrid SUV, 2WD - 33/28 - $44,660
Toyota Highlander Hybrid SUV, 2WD - 33/28 - $33,030

*NA = Not available
Sources: Manufacturers & 2006 Fuel Economy Guide published by the U.S. Environmental
Protection Agency and the Department of Energy.

Issue 25

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