Clean Diesel: Too Good To Be True? : 13.7: Cosmos And Culture Last month, Alva Noë's family bought their first new car — a VW Golf Sportwagen TDI — paying premium for what they thought was a fuel efficient, clean diesel; he tries to understand what went wrong.
NPR logo Clean Diesel: Too Good To Be True?

Clean Diesel: Too Good To Be True?

Jens Meyer/AP
A worker checks a Passat Variant during a press tour at the plant of the German manufacturer Volkswagen Sachsen in Zwickau, Germany.
Jens Meyer/AP

Diesels are more expensive than gasoline powered cars. But they drive better; they've got better torque. And they're way more fuel efficient.

The downside is that they're dirty. They spew deadly particulate matter and nitrogen oxides (NOx) that make it hard to breathe.

In Europe, diesels have been an economical alternative to gas-powered vehicles in part because, historically, they've been taxed at a lower rate. However, Europe has not effectively dealt with the pollution problem (although, since 2009 they have required particulate filters). There's no European agency with anything like the regulatory and enforcement might of the United States EPA. Emissions standards across Europe are less stringent in general, and they're not fuel neutral: Diesels are allowed to pollute more than gasoline vehicles. But this may be changing: Paris has recently announced the intention to ban diesel cars altogether by 2020 and London may follow suit.

The United States leads the world in emissions safety standards. In 2007, the U.S. implemented new fuel-neutral performance standards that put the rest of the world to shame. (Indeed, current EPA standards — so-called Tier 3 — to be phased in after 2017, set an even higher bar — NOx emissions for diesels meeting European standards would be between 7 and 30 times higher than that permitted under current U.S. law.

And this is why diesel passenger vehicles have been a rarity on American roads. It's not that you can't make a clean diesel. You can. You need to build in filters and after-treatments at the tail pipe. Truck manufacturers figured it out more than a decade ago. Until a few years ago, car makers hadn't figured out how to make an affordable diesel passenger vehicle that would meet Tier 2 and Tier 3 standards.

But in the last few years, diesels that are in compliance with the demanding cleaner standards have hit the roads. VW and BMW, but also Mercedes and Porsche, have diesels in the U.S. market. And it isn't only the Germans who, apparently at least, have solved the engineering feat of making the clean diesel. Chevrolet and Jeep also have diesels cars.

That's why people like me — yes, I've got a personal interest in this! — jumped in and bought. Last month, my family bought our first new car ever, a VW Golf Sportwagen TDI. We paid a diesel premium for a fuel efficient, clean car with good performance.

It is now known that Volkswagen did not find an engineering solution. They found a software trick to defeat the testers. Instead of introducing technologies that lowered NOx emissions, they introduced software that fooled inspectors into thinking emissions were compliant.

It was the International Council on Clean Transportation (ICCT) that discovered VW was cheating — and it made the discovery, remarkably, by accident. The council had hypothesized that the discrepancy between real-world road tests and laboratory tests that is so much in evidence in Europe would not be a problem with diesels in the U.S. To their surprise, they found emissions on the VWs they tested were out of wack. Emissions on the road exceeded those in the lab, as well as the emissions permitted by law. The ICCT reported their findings publicly as well as to VW and the EPA. The rest is, well, the rest is unfolding now.

Actually, it's worth noting that the EPA challenged VW right away and VW made a voluntary recall last year. They claimed to have fixed the problem. But they didn't. (This is all laid out in the EPA notice of violation.) Volkswagen only came forward and admitted its deliberate installation of defeating devices (software that conceals real emissions) when the EPA, about three weeks ago, threatened to withdraw the company's right to sell new cars in the U.S. in 2016.

So, what's the bottom line?

First, there's no reason you can't make a clean diesel. U.S. regulators require this of car makers and some of them, for example BMW, seem to have found a way to do it. The promise of clean diesel remains better performance and fuel efficiency. Car makers have not yet been forced to make really clean diesel in Europe — and it's high time they start. A first step will be enforcing new testing standards internationally that look at real-world, on-the-road performance and not just emissions in the laboratory, as an ICCT publication concludes.

Second, as Katherine Blumberg of the ICCT told me: More than half of the passenger vehicles sold in India today are diesels without particulate filters. These vehicles emit both very high NOx and particulates. They are deadly. This must stop.

The third upshot, for me personally, is, well, anger. I don't want to drive a car that harms the environment! VW lied to me and tens of thousands of others. This needs to be made right. This is about the health and safety of real people.

Thanks to Katherine Blumberg of the ICCT for extensive discussion of this topic. We're old friends.


Alva Noë is a philosopher at the University of California, Berkeley, where he writes and teaches about perception, consciousness and art. He is the author of several books, including his latest, Strange Tools: Art and Human Nature (Farrar Straus and Giroux, 2015). You can keep up with more of what Alva is thinking on Facebook and on Twitter: @alvanoe