Promoters of clean diesel passenger cars are working to establish parity among U.S. alternative energy choices and the public relations battle lines are drawn on several fronts.

Like every other technology, diesels have their detractors, including those who comment on this site categorically stating “clean” and “diesel” do not belong in the same sentence.

In their favor, today’s ultra-low-sulfur (ULSD) burning turbo diesels are among the most efficient engines produced – with up to 30-percent better fuel economy than some comparably sized gasoline engines, up to 50-percent better torque, and their CO2 emissions can be up to 12-30 percent less.

One gallon of gasoline has the energy value of 125,000 British thermal units (BTUs) compared to diesel’s 147,000 BTU.

Durability wise, diesels offer comparable maintenance schedules and lifecycles says Audi’s Product and Motorsports Communications Manager, Mark Dahncke.

Going further, the advocacy group Clean Diesel Delivers reiterates the concept that has anecdotally floated out there for years.

“The efficient combustion that occurs within a clean diesel engine makes it more durable than a comparable gasoline engine,” says the group of engines that must be robustly built to handle high combustion pressures.

2014 Chevrolet Cruze Diesel.

2014 Chevrolet Cruze Diesel.

More provable is they tend to hit their claimed EPA numbers with greater ease than some hybrids, said automotive analyst, Alan Baum, who noted also ownership experience is “excellent,” with ULS diesel now readily available, and resale values can be strong too.

Working against diesels however is diesels tend to cost some degree more than gas counterparts, and since 2005 diesel fuel has typically cost more than regular gasoline. As we write this, ULSD has spiked 66 cents more per gallon than regular gasoline, and 33 cents more than premium.

So much for those efficiency gains …

In Europe things have been entirely different, with pricing, taxation and driver needs highly favoring diesels. In the UK, more than half of all passenger cars are diesels, according to the Guardian. Contrast that with the U.S. market where diesels hover around 1 percent of the U.S. market and have slowly ticked upwards from 0.73 percent in 2010, 0.78 percent in 2011, 0.82 percent in 2012.

Yes, despite some tangible advantages, they remain a tough sell.

In recent years, some automakers have nixed plans to proffer new models, and are not even trying to push against resistance.

But the the European market has meanwhile developed some superb, powerful, long-legged diesels and among others, Audi is trying to carve out a bigger piece of the American pie.

Leveling the Playing Field

Dahncke said Audi has lobbyists in Washington advocating a “technology neutral” alternative energy policy.

So far, he said, significant headway is not known to have been made, but in November Audi announced it’s rolling out four new TDI models and it’s increasing promotional awareness campaigns just the same.

One message Audi wishes to make clear is presently hybrids may receive politically biased favoritism in certain states. Electrified cars may receive solo access to high occupancy vehicle lanes as a perk, but no diesels do, he said.

diesel vs hybrid

An Audi A3 diesel sportback is EPA rated at 42 mpg on the highway, within the realm of some hybrids’ real world or actual mileage, and beating a Lexus ES300h, for example.

What’s more, diesels used to be eligible for perks. Consumers who bought clean diesel vehicles between Jan. 1, 2006 and December 31, 2010 were eligible for up to $3,400 in tax credits based on the weight, fuel efficiency rating and emissions levels.

More recently, various people in the industry have proposed a high gas tax such as is in place in Europe to help even the differences out, but this too is not known to be gaining sufficient traction at the moment.

A survey by Harris Interactive polled 1,629 regular drivers in September and found that 66 percent thought the government should offer a tax incentive on clean diesel vehicles. Further, 59 percent of 18-34 year-old drivers said that if the cost of diesel was on par with gasoline, they would purchase a diesel-powered vehicle.

This contrasted with older drivers who were not so positively predisposed.

“One of the reasons we are seeing this disparity between age groups may be because younger generations don’t have the same misconceptions about diesel as older generations,” said Scott Keogh, President, Audi of America. “The objective is to reward efficiency, and diesel is an efficient alternative available today. We need to level the playing field.”

Diesel prices are affected by global markets but state taxes also vary.

Diesel prices are affected by global markets but state taxes also vary.

Some state rules penalizing diesels date back to legislation focused on road-going trucks that polluted heavily, and threatened roadways with more wear and tear as well.

However a survey released Dec. 4 by the Coordinating Research Council along with the Health Effects Institute has found even larger trucks since 2010 have been significantly cleaned up.

The study found a more than 60 percent reduction in emissions of nitrogen dioxide as compared to 2007 models, and 99 percent reduction compared to 2004 models.

Nationwide, diesel is taxed above the fuel of choice, gasoline.

Nationwide, diesel is taxed above the fuel of choice, gasoline.

Coming back to passenger vehicles, Audi is running a series of commercials to attempt to shatter old notions of clunky, noisy, smelly cars that may or may not start properly in cold weather.

Despite the perceived bias in favor of electrified technology, Audi is continuing to make factual points where it can to at least get people to re-think, and reconsider.

How Clean Really?

But while automakers – including GM with its Chevy Cruze – and other proponents push for diesel acceptance in America, in the UK where they’ve come to comprise over half of new vehicles sold, opinions are shifting.

In November, the Guardian said real world driving is showing some types of pollution are not being effectively controlled despite advanced emission control technologies.

“The air pollution penalty from diesel cars is often justified in terms of the saving in CO2 emissions compared with petrol,” wrote the Guardian, “However, new analysis is calling this orthodox view into question. If climate warming emissions of black soot are considered along with the difficulties of producing sufficient diesel to meet demand, then the climate change benefits from diesel largely disappear.”

Volkswagen Jetta TDI – the top selling diesel in America.

Volkswagen Jetta TDI – the top selling diesel in America.

The Guardian writes frequently on climate change and has documented studies casting doubt upon “clean diesel” versus petrol. It noted the Japanese have improved gasoline engines to return cleaner emissions in urban areas.

“Additionally, with the recent classification of diesel exhaust as carcinogenic, it might be time to reconsider the recent boom in diesel fuel use across the UK and Europe,” wrote the publication.

So with a call for the jury to step out in diesel-saturated UK and EU, and fence sitters at 99 percent of all Americans, it would appear challenges remain.

Audi’s Dahncke says its premium emissions tech is effective while generally acknowledging other perceived obstacles. He also made clear Audi is in no way opposed to hybrids, and is in process of launching electrified cars including its A3-based e-tron PHEV in 2015.

Some driver needs may be best met by diesels however, he said, and this is part of the message Audi wishes to impart.

For example, large SUVs like the three-row Q7 make sense in diesel configuration, and excel as luxurious, powerful and fuel-efficient alternatives.

2015 A8 TDI.

2015 A8 TDI.

The Audi A8 TDI, a luxurious and powerful car with WiFi and massage seats among its stylishly designed accouterments can travel 800 miles on a tank.

Audi’s sedans tend to have largish fuel capacity – around 24 gallons or so – which combined with respectable highway efficiency, enables long range as a matter of course.

There are fewer diesel stations in America, but as analyst Alan Baum – and Audi – have pointed out, there are enough.

As for ULSD costing more, the U.S. Energy Information Administration (EIA) cites three reasons:

• High worldwide demand for diesel fuel and other distillate fuel oils, especially in Europe, China, India, and the United States, and a tight global refining capacity available to meet demand during the period of high economic growth from 2002 to mid-2008.

• The transition to less polluting, lower-sulfur diesel fuels in the United States affected diesel fuel production and distribution costs.

• The Federal excise tax for on-highway diesel fuel of 24.4 cents/gallon is 6 cents per gallon higher than gasoline tax.

gas.diesel prices

The advocacy group Clean Diesel Delivers notes the inequity of the situation as well.

“Diesel drivers already pay a 33 percent federal tax penalty every time they fill up with diesel fuel,” it says front and center on its home page. “Any attempt to raise taxes or fees to support transportation funding must be fair and balanced and not put the burden on consumers who drive diesel cars.”

If you agree, it has a petition it would like you to sign.

And for more info, you can check Audi’s page on the subject.

Judgment Call

Even before the advent of ultra low sulfur diesel last decade, and advanced emissions controls, America has had a minor contingency of drivers who favor diesels.

Source: Edmunds TCO Calculator.

Source: Edmunds TCO Calculator.

Questions about fuel prices and emissions aside, regarding drive characteristics, durability, and other quality considerations, diesels do make a strong argument compared to regular gas burners.

Like any other buying decision, total cost of ownership ought to be weighed, assessing depreciation/resale value, loan interest, taxes and fees, insurance premiums, fuel costs, maintenance, and repairs.

Comparing an Audi Q7 Quattro diesel versus gas, the numbers are essentially a toss-up with not even $700 separating estimated 5-year ownership cost.

Audi will have more models for which data and cost estimates is not yet available, but these too threaten to be competitive in relative terms.

Source: Edmunds TCO Calculator.

Source: Edmunds TCO Calculator.

Unlike sister company Volkswagen, Audi does not sell as high of volume, and by itself likely won’t significantly shift the U.S. take rate for diesel sales.

Dahncke said Audi has been beating its sales projections, is up 13 percent year over year, and in November had sold 150,000 total cars – its goal for all of calendar year 2013 a month early.

By 2020 it would like to “profitably” sell 200,000 units per year, and at its present growth rate it is well on track.

With several new models on the way, the bullish-on-diesel company says the time is right, and aims to make these successful too.

Now if only legislators would be so kind as to shift the cost equation to make it an absolute no-brainer.

Until then, Keep your pencil sharpened, and your mind open.