Diesel’s reputation has taken a big hit in recent years, most notably because of the Volkswagen emissions scandal. The German automaker’s malfeasance rocked perceptions that the fuel—because it is more efficient than gasoline and has become cleaner due to stricter regulations and new technology—would dominate the transportation sector for decades to come. In the aftermath of the VW scandal, in Europe, where roughly half the cars run on diesel, a handful of countries have set ambitious plans to ban diesel and sell only electric cars beyond 2030-40.
Despite the behavior of the 2015 scandal and its continued fallout, diesel remains an effective tool in reducing total petroleum consumption, and remains a viable part of a larger strategy to reduce oil dependence.
Despite the behavior of the 2015 scandal and its continued fallout, diesel remains an effective tool in reducing total petroleum consumption, and remains a viable part of a larger strategy to reduce oil dependence. As electric vehicle technology gains traction, efficiency improvements are essential. Recent calls to ban diesel—throughout Europe in particular—are premature. Banning diesel will impede goals to reduce greenhouse gas emissions, inhibit consuming countries from reducing demand for oil, and stifle advancements in auto industry innovation.
Clean diesel was supposed to sharply improve efficiency and bring about environmental benefits by cutting down on the amount of NOx emitted by vehicles. It would be a win-win for consumers, auto makers, and environmentalists. But Volkswagen, the only company that made sufficient inroads in the U.S. with diesel passenger cars, installing software on its diesel-powered vehicles that provided false emissions data has spurred the perception that diesel couldn’t be a “clean” fuel.
Diesel fuel remains a top environmentally-friendly alternative to gasoline because it’s one of the most energy dense fuels available with 30 percent more efficiency than gasoline.
This is a misperception. The diesel engine has led to some of the most environmentally friendly vehicles that are sold at competitive prices. Diesel fuel remains a top environmentally-friendly alternative to gasoline because it’s one of the most energy dense fuels available with 30 percent more efficiency than gasoline. As Wired pointed out: “Automakers love diesels because they help them meet increasingly stringent fuel economy standards. They offer lots of torque for great off the line acceleration, don’t suffer from the cost or range anxiety associated with electrics, and finding a place to refuel is generally easy. Diesels are most efficient on the highway, good for drivers who spend more time in the suburbs than in the city.”
Don Hillebrand, the director of energy systems research at Argonne National Laboratory in Illinois and the former president of the Society for Automotive Engineers, told Live Science that diesel technology that combines clean-emission techniques, power and fuel economy will play a major part of the vehicle fleet in the future.
VW’s cheating should not undermine efforts by other manufacturers that produce fuel efficient diesel-fueled cars that meet emissions standards. “Not only did [Volkswagen] cheat, but then they went out and crowed about how clean they were,” Jack Ewing, who wrote a book on the VW scandal, told the Atlantic in an interview. “That turned what was already a pretty serious regulatory violation into a consumer fraud. And that’s one reason why it turned out to be so expensive for Volkswagen. They did everything wrong you possibly could.”
VW’s cheating should not undermine efforts by other manufacturers that produce fuel efficient diesel-fueled cars that meet emissions standards.
Daimler is one good example of an automaker making strides in reducing the environmental damage from diesel without compromising performance. In Daimler’s vehicles, the company injects an extra fluid (called urea) to convert NOx into less detrimental materials and meet emissions requirements. This method, which is called BlueTec, doesn’t undermine the vehicles’ fuel economy or power. The Mercedes-Benz E250 Bluetec, for instance, gets 42 mpg, versus the average of 26 mpg for 2017 vehicles. Other diesel vehicles have similar high fuel economy, particularly on the highway.
Back in the 1970s, diesel was marketed in the U.S. as an alternative to gasoline to save fuel, but consumers saw diesel as being loud and smelly. As a result, it has for the most part been used in trucking and shipping in the U.S. Still, VW’s diesel cars were able to make headway in the U.S., highlighting how important it is that the company’s scandal doesn’t undermine the fuel’s reputation longer term.
Ill-advised policy to ban diesel will bring unforeseen consequences for energy security.
In Europe, the stakes are even higher because of penetration rates of diesel vehicles. In the late 1990s, the European car market moved structurally toward diesel to improve fuel economy and lower CO2 emissions. Diesel cars have also benefited from favorable policies such as tax incentives to make them more attractive to consumers. With this, the European auto sector is heavily dependent on diesel, which means the fuel is not going away any time soon. Germany’s Chancellor Angela Merkel, whose country may impose a ban over time similar to France, Britain and India, admitted recently that diesel is needed as a bridge fuel to meet environmental goals. In emerging markets, diesel will be a main component of oil demand growth, not only for trucking, marine, and freight, but also in passenger cars given their better fuel economy. In fact, among fuels in the transportation sector, diesel is expected to rise by the largest amount between now and 2040, according to the EIA.
Moving quickly to reduce demand on oil is critical, and the technological innovations needed to get there will include not only EVs and hydrogen vehicles, but also ones that run on diesel. In the interim, ill-advised policy to ban diesel will bring unforeseen consequences for energy security.