SA is receiving new diesel models including the performance VW Golf GTD. Picture: QUICKPIC
SA is receiving new diesel models including the performance VW Golf GTD. Picture: QUICKPIC

Diesel power will still be critical to meet emission regulations, Volkswagen’s boss says, but he insists small diesels are dead in the water.

With a marked shift away from new diesel cars across Europe, VW brand chairman Herbert Diess believes petrol engines with 48V mild-hybrid electric boosting systems will take over in small cars.

But high-mileage cars and larger, more expensive cars and sport utility vehicles will still need diesel power to meet 2020 European emissions laws and to help countries meet their Paris Accord CO2 obligations.

"We don’t believe in small displacement diesel so the emissions are too hard to do with them for the price," Diess insists. "We wouldn’t put so much money into a 1.6l diesel for the future but we will make it compliant for as long as we have got it."

Diess’s overview of the future of small cars is that their powertrain options will narrow to mild-hybrid systems.

He says people who drive less than 25,000km a year will not benefit from diesel power and neither will they pay for plug-in hybrids.

"Maybe mild hybrid is in the Polo’s future. Our rationale in the A0 segment is that diesel will disappear because it’s getting so expensive," Diess says.

"All the emission systems will be so expensive and there will be very few cars in the Polo segment [and probably in the Golf segment as well] which do enough mileage to compensate for the extra costs.

"Our rationale is that in the next generation of Golf we will bring in 48V mild-hybrid drive (MHD), which will be on CO2-wise very similar to diesels for shorter distances.

"With MHD they get the same CO2-sticker, and if they drive less than 20,000km a year in the real consumption they are on par with the diesel.

"For the long-distance driver who drives 25,000km or more a year, then diesel still makes sense, but few Polo drivers do 25,000km a year."

The car industry in general has been under public and media pressure, particularly in Germany, over perceived ethics around diesel emissions, which has resulted in lower courts threatening to impose diesel bans in cities such as Stuttgart, Munich and Hamburg.

Pressure to meet emissions regulations could make small diesel engines too expensive to produce and sell. Picture: NEWSPRESS UK
Pressure to meet emissions regulations could make small diesel engines too expensive to produce and sell. Picture: NEWSPRESS UK

But Diess says much of the head has gone out of the diesel debate, particularly in the political arena in Germany, although former Volkswagen Group powertrain development director Wolfgang Hatz was recently arrested in Germany over the Dieselgate scandal.

"I think most of the politicians also want to avoid [diesel] restrictions in the cities so we have a much more rational discussion now," says Diess.

"I think the diesel discussion now is depending much more on political decisions than on the industry. It’s a question for society and I’m really happy about the discussions we are having in Germany…."

While it’s possible to make diesel engines clean enough to meet international emissions limits for CO2 and NOx, it is expensive technology, with the cost moving on a sliding scale depending on the limits.

"The technology is there to make it clean and its future is the same as electric cars — they depend on society and politicians. It’s not a technical problem. It’s a political one.

"Every technology has advantages and disadvantages. The diesel advantage is of being efficient for the customer and also has the ability to be clean and help with CO2 emissions.

"Gasoline engines are less efficient but they are cleaner. However, they also have pros and cons.

"Even electric cars have the problem of how to produce the energy — is it clean energy or not? Then we come to the question of how to produce the battery," he says.

Diess refuses to be drawn on when the car industry will build its last diesel engine for a passenger car, insisting it is up to politicians and pointing out that before 2035, most countries will change their governments five or six times.

"The remaining lifespan of diesel will depend a lot on regulations. If people come to the conclusion that the tax incentive on diesel [0.20 cents a litre in Germany] should be removed, and government would remove that, it would change rapidly.

"So far in Germany over the last two or three weeks we received a lot of commitment to the diesel from the politicians. The politicians are restating that we need the diesel, it’s clean technology now."

Even if cars older than EU6 are banned or retrofitted with Selective Catalyst Reduction (SCR) systems, Diess doubts they would make any difference to urban air pollution, which is seen as diesel’s Achilles heel. "I still think you have to see that cars have only a little contribution to what happens in the cities" he says.

"Even if you get all the diesels out of the city we will not achieve the limits. The emissions are coming from so many different sources that the cars are less than 20%.

"It needs a much more comprehensive solution than just banning diesels. I think this is finally becoming more understood," Diess says.

Insisting there is no rational reason the car industry couldn’t still be selling diesel-powered cars in 2035, Diess reiterates that diesel’s future is political.

"When diesel finishes is kind of guessing and it’s a decision of politics. It’s nothing to do with customers or car makers but it’s government policy.

"In China it will be electric because they decided they would do it. In countries such as the US, if you apply the same emissions legislation to diesel and if you don’t have these tax schemes then diesel remains strong in lorries and transport.

"If you change the rules, then diesel will stop. In Europe we have different rules and diesel is much cheaper than gasoline."

Interestingly, Diess’s comments come at a time when more diesel derivatives are arriving in SA. Recently VW launched the Golf GTD, the diesel equivalent of the GTi and Mini is finally bringing a diesel version of the Mini in the form of the Countryman D.

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