Once diesel fuel was touted across parts
of the world as a readily available solution to
increase fuel economy. Diesel engines were praised
as heavy-duty, hardworking, fuel-sipping engines that were great for some
of the hardest jobs and heaviest machinery — hauling, clawing through the
dirt and driving long distances. Their reputation as efficient and long-lasting
engines made them a popular choice across Europe, one of
the world's largest car markets. They were supported by government
incentives and embraced by major automakers. For a while, it looked like
diesel engines could be one of the best available technologies for reaching
ambitious fuel economy targets. Then the case for
diesel seemed to crash. Cities where diesels were common struggled
with extremely high levels of air pollution. Global health authorities
determined diesel fuel to be carcinogenic. In 2015, German automaker
Volkswagen, one of the world's largest car companies, shook the
industry when executives admitted the company had cheated on
diesel emissions tests. Executives were fired and jailed. Volkswagen was on the hook for billions
in fines and payouts, and some wondered whether the scandal spelled the
beginning of the end for diesel engines themselves. At the same time, hybrid and
electric vehicles increasingly became, for many, the best new hope for providing
low emission or even emission free transportation and equipment. But diesel advocates say diesel
is not done yet. It is still widely used in
heavy machinery and commercial applications. Companies are developing new technology,
such as pollution filtering systems and renewable biofuels that could
keep diesel relevant and widely used for years to come, even
as solutions for reducing toxic emissions. Within the truck markey, the diesel is a
huge player as far as, you know, the amount of vehicles that we
produce with diesel, certainly in heavy duty. And there's a constant
desire for more capability. The diesel engine was named for
its creator, Rudolf Diesel, a Paris-born son of Bavarian immigrants. Diesel was an engineer who worked
on refrigeration technology during the day. But in his spare time, nursed
ideas for an engine more efficient than the typical designs of his time. He designed an engine that worked
in a manner similar to conventional internal combustion engines, but with
a few crucial differences. In an internal combustion engine, diesel
or otherwise, fuel and air combined inside a cylinder
chamber where they combust. The explosion pushes a piston, which
turns a crank shaft and ultimately turns the wheels that move a vehicle. In a typical gasoline engine, a spark
plug ignites the fuel and air mixture inside the cylinder. But Rudolf Diesel determined that
no spark was necessary. His design simply compressed the air in
the cylinder to the point that the air was so hot it would
cause the fuel to combust. As soon as it was
injected into the cylinder. Diesel's basic design innovations are still
seen in diesel engines today. The design of the diesel engine gives
it some of the advantages so appreciated by fans. Diesel engines tend to get better
fuel economy than gasoline engines, sometimes much better. And they can also deliver a great deal
of power to the wheels at low speeds, making them excellent for heavy
machinery and vehicles that need to haul, whether that be freight
trucks, construction equipment or trains. Diesel fuel is also different from gasoline,
and it is more energy dense, meaning more energy can be extracted
from diesel than can be extracted from the same amount of gas. Diesels get about, on an average
basis, about 30 percent more energy efficient than a
comparable gasoline vehicle. So that comes from two things. The fuel itself has more energy potential
in it, and then the engine burns that fuel more efficiently. So those
two things together make diesel the most energy efficient
internal combustion engine. Over time, their fuel saving potential
made them highly desirable choices in countries where governments were
trying to reduce carbon emissions. Lower carbon dioxide emissions were one
of the reasons the European Union began pushing the fuel in the 1990s. Around the time climate change became
a serious global issue and countries began signing on to major global
carbon reduction agreements, such as 1997's Kyoto Protocol. For a long time through most of the 90s
and into the 2000s and a lot of countries in Europe, diesel was the
majority, represented the majority of light vehicle sales. In some markets like in Italy it
got as high as 90 percent of the market was diesel engines. And Germany and France
was also very popular. But that, in North America, diesel
never really caught on quite as much, except during periods where we tended
to have very high fuel prices. However, diesel engines do
have their drawbacks. Whereas diesels are good with low end
torque, it is easier to get higher horsepower in a gasoline engine. That is why diesel engines are typically
found on large trucks and heavy machinery, but seldom found on
sports cars or race cars. There have been other drawbacks that
eventually gave diesels a bad reputation they are
still battling today. Overall, diesel engines produce less
CO2 than gasoline burning engines, helped by the fact that
they burn less fuel. However, they produce higher concentrations
of other hazardous pollutants, especially nitrogen oxides and very
tiny particles, commonly referred to as PM 2.5. The European countries that embraced
diesel considered it a tradeoff. Sacrificing some losses in air quality
for gains in CO2 reduction. Many European countries put tax advantages
in place to encourage diesel engine adoption. These incentives sent
diesel car sales skyrocketing throughout Europe. But over time, cities
such as Paris showed signs of dangerously high pollution. European emissions standards have restricted
pollutants such as nitrogen oxide since at least the 2000s. But for years, laboratory tests
were easy to exploit. As the European Environment Agency
noted in a 2019 report. In 2012, the World Health Organization
said it considered diesel exhaust carcinogenic. Several studies over the years
have shown harmful levels of nitrogen oxides and other pollutants in
European cities, often high above legally allowed limits. Perhaps the biggest hit to diesel's
reputation was the cheating scandal that rocked Volkswagen and other
automakers beginning in 2015. The German carmaker, one of the largest
in the world, had been heavily invested in diesel fuel and marketed
for its fuel economy benefits. But starting in 2015, revelations began
to surface that the company had installed software in cars designed
to manipulate emissions test results. These defeat devices were able to recognize
when a car was being lab tested, as opposed to being driven
in real world conditions and thus calibrate the engine to cheat the
test by temporarily producing emissions low enough to
comply with regulations. Once on the road, the cars
outfitted with these devices were often releasing pollutants that far
exceeded legal limits. Volkswagen has had to pay roughly
35 billion dollars since 2015 and penalties, fines, settlements
and other payouts. The scandal seems to have marked a
turning point in Europe's history with diesel. Following the Volkswagen scandal,
diesel sales did drop off dramatically in Europe, even though it
was still more cost effective to drive a diesel engine there. It has dropped significantly. Our own stats, globally,
between 2016 and 2018, while overall vehicle sales and
electric vehicle sales increased globally by about one percent. Diesel sales dropped by about nine
percent globally in that same timeframe. Of course, in Europe, where
diesel was most popular, it dropped off the most. In 2015, diesel's share
of new passenger cars in Europe was about 51 percent. By 2018, that share had
fallen to 36 percent. That is the lowest share of
total new car registrations since 2001, according to industry data
firm JATO Dynamics. Association with the high profile
VW scandal hurt diesel's reputation. But perhaps even worse was the
talk among European politicians of banning internal combustion cars entirely, including
diesel, from major cities. The UK said in 2020 it plans to ban
the sale of both new diesel and new gasoline cars by 2035. France has also plan to end the
sale of internal combustion cars by 2040. Automakers such as Volvo and Nissan have
said they plan to either reduce their share of diesel vehicles
or phase them out entirely. In the wake of the scandal, VW
made a pretty sharp turn toward electrification. The company said in December
2019 it planned to produce one million electric cars by 2023, sooner
than the 2025 target it had previously set. Of course, there is hardly
an automaker in the world that isn't moving into electric vehicles. That poses some real competition for
diesel engines, even larger vehicles such as buses and delivery trucks can
run well on electric and hybrid power trains. Encroaching on territory diesel
once had pretty much to itself. Vehicles that operate in a local
area like trash trucks, buses are increasingly shifting towards
electric power trains. Local authorities are buying a lot
more electric buses because they're cleaner, quieter or more
efficient, cheaper to operate. Companies like Amazon that operate huge
fleets of delivery vehicles says those FedEx and UPS and Amazon vans
that deliver all its packages to you, those are traditionally been
powered by diesel engines. But, you know, that's
starting to change now. Amazon invested $800 million last year
in an EV startup called Rivian. And UPS and FedEx are doing... they're also buying a
lot more electric vans. So for local operations where those vans
are coming back to a depot at night, it's easy to plug those
in and charge them overnight. Not a big deal. For
now, diesel is still everywhere. Most of the farm equipment in
the United States runs on it. It is still very common in
heavy construction, mining, shipping and marine transport and much of public transit. Though companies such as Tesla
are venturing into electric long-haul trucks, diesel is still the powertrain
of choice for that sector. The last place where you'll likely see
diesel is in those long-haul trucks where it's still a challenge. You need so much battery in those
things to go electric with those. You know, they're driving, you know,
thousands of miles across the continent, that it's gonna be a
while before those get electrified. But, you know, the emissions, the diesel
emissions are less of a problem with those because they tend to be out
more out in rural areas when you're driving across the country. Whereas, you know, the diesel emissions
aren't...where they are a bigger problem is in urban areas. So the urban local delivery
vehicles — they're going electric. The long-haul stuff is going to go
stay diesel for a while yet, but probably by the late 2020s, we'll
start seeing those going electric as well. Diesel advocates say it is too soon
to count the fuel out and there may be further
opportunities for growth. Companies are developing technology that can
reduce the emission of the harmful pollutants that have run
diesel into trouble before. All diesels sold in the United States
is ultra-low sulfur diesel, which is a form of the fuel that contains
a tiny fraction of the sulfur contained in older forms. This fuel allows diesel
vehicles to be fitted with new pollution, reducing devices. Today we know that operating on the
nation's roads that about 43 percent of all commercial vehicles registered and
operating are the newest generation of diesel. So that means they have
the full suite of particulate control and advanced selective catalytic reduction
systems, diesel exhaust fluid, et cetera, that enable them
to achieve near zero emissions. Companies are also investing in renewable
biofuels, which are refined from crops or organic waste. Many diesel engines can now use a
blend of 20 percent renewable fuel and 80 percent petroleum based diesel,
commonly called biodiesel, but known more technically as B20. Some are going even further and
using entirely renewable fuels and diesel engines. The city of San Francisco
converted its fleet of municipal vehicles to totally
renewable diesel fuel. The advanced renewable biofuels, like
biodiesel, enabled the carbon footprint to be reduced from a
diesel engine by anywhere from additional 20, up to as much as 80 percent,
if you're using the most refined and advanced processing of
those biodiesel feedstocks. Diesel also appears to have crept back
into a few key segments that are especially popular among American consumers
and profitable for American automakers: pickup trucks and
sport utility vehicles. Diesels provide greater
efficiency, greater range. And a light duty diesel, you can drive
from going Duluth to Dallas on one tank of fuel, compared to gas —
35 miles per gallon on the highway. And if you look at the torque curve,
the torque curve is a very low R.P.M. In 2019, all three U.S. automakers had, for the first time in
years, at least one diesel, full size, half-ton pickup truck
in their lineups. Diesel engines are also options on
mid-sized pickups such as the Chevrolet Colorado. And General Motors is offering
diesel engines on its Chevrolet Suburban and Tahoe sport utilities. Those pickup trucks and some great
options for those that really like off-roading and Jeep. The Wrangler and the Gladiator both
have diesel engine options in those vehicles. So we get a lot of grunt
for those folks that really do true off-roading activity. Diesel's low end torque is really a
kind of thing that that that segment really likes. So I think there's
great opportunities for diesel in the light vehicle segment in these
bigger vehicles and these performance veterans. Much of the auto industry
is betting that the future is electric. But the bridge to fully
electric cars, trucks, trains and construction equipment could be
a long one. The diesel industry is betting
consumers and governments will want effective solutions they can
deploy along the way.
