Sweet Diesels Few & Far Between

I've been a fan of diesel cars ever since I wrote an article for Smithsonian magazine a few years ago about how people were making their own fuel out of waste grease or turning the grease into biodiesel at home. After doing the research, I became very optimistic about commercial biodiesel becoming available quickly, so I went out and bought a used 2002 Volkswagen Jetta diesel.

(Biodiesel can be used in existing diesel engines without modifying the engines. If you use strained grease, you need a dual fuel system so you can start and stop the engine with petroleum diesel. Otherwise, the gel in the grease creates clogs.)

I've been very happy with the Jetta: it rides like a much bigger car, even at fast highway speeds, and gets more than 40 mpg at the same time! Unlike pokey gasoline engine cars or hybrids that get similar mileage, the diesel has plenty of power--it's just plain fun to drive.

However, my hopes for commercial biodiesel have not turned into reality. There are all sorts of obstacles to getting the fuel distributed nationally, not least of them that regional fuel depots don't want to invest in necessary new facilities to handle it. Furthermore, we've been shipping most U.S. biodiesel to Europe where diesel cars dominate. And then, when the price of petroleum diesel finally dropped to more reasonable levels, it put biodiesel--made here mainly from soybeans--at a competitive disadvantage.

Even so, when we recently decided to get rid of our gas-powered family-sized car that we use for long trips, I thought I'd trade the Jetta for a new VW Passat diesel, which Volkswagen had promised to bring to the U.S. sometime this year. It's a bit larger and therefore a bit safer on highways where you dance with tractor-trailers, and yet would get excellent mileage.

But no. A spokesperson for VW says they've changed their minds, and there will be no Passat diesel anytime soon. Bummer.

Unfortunately, there are very few diesel cars yet available in the U.S. You can get an improved Jetta diesel or a diesel SUV in a luxury brand, but there are very few to choose from otherwise.

This despite the fact that diesels get 20 to 30% better mpg than comparable gas cars with all the torgue and durability you could want. And, thanks to new technology and ultra-low sulfur petro diesel, new models meet the strictest (California) air pollution standards.

Still, I was left with the reality that we needed another car, so I did the research, looking for a full-size gasoline vehicle with good mileage. So discouraging, because essentially there are none. Then I discovered the Mercedes Benz E320 diesel, introduced in 2008, with the new clean technology. It promised to get about 25 mpg in local driving, and in the 30s on the highway.

I located a used one with about 20,000 miles on it, trekking over the George Washington Bridge in New Jersey to see it. I got in for a test drive, and I hadn't gone 200 yards before a smile spread across my face: this is one sweet ride!

Quiet--no more loud diesel noise. Smoke-free--no more nasty tailpipe emissions. Smooth. Everything about this vehicle is smooth and powerful. I bought it.

It cost more than we'd expected to spend--although buying it used saved a lot--but we figure it will last a good 10 years. And I've been averaging close to 30 mpg in my combined stop-and-go and local highway driving.

Too bad the automakers are so slow about bringing more sweet diesels to U.S. car buyers.