Why Diesel Will Survive The Current Push For An Electric World
The whole world is going electric, or so we’re told. But the reality is that while the world may eventually switch to 100-percent electric passenger vehicles, it’s not going to happen overnight. In fact, you’re likely going to see diesel, gasoline, and hybrid-powered vehicles dominate U.S. roadways for at least another two decades. So why all the hype about battery electric vehicles (BEV’s) in recent years? Long story short, BEV technology—and in particular battery technology—has come a long way, and practically improves on a daily basis. Sprinkle in a little “zero emissions” make-believe, emphasize the obvious reduction in dependency on foreign oil, get every OEM automaker onboard, and you’ve got a full-blown BEV movement.
If only it were that cut-and-dried. Beneath every electric headline and glamor shot there are a lot of items going undiscussed. Among them are the BEV’s range and charging disadvantages, the fact that they’re cost-prohibitive for many Americans, shift greenhouse gas emissions from the tailpipe to the power plant, and lack the same type of 100-year infrastructure internal combustion engines (ICE’s) enjoy at the present time. Beyond that, all the advancements made in internal combustion engines (ICE’s)—especially diesel technology—over the years is being ignored. Not here. In the following pages we’ll spell out just how far diesel emissions have come, shine a light on all the modern BEV’s shortcomings, and make a case as to why diesel and gasoline will continue to co-exist with electric for years to come.
Above all else, the promise of reduced emissions has driven the electric vehicle craze, but pollution—in one form or another—has always been a concern in the transportation world. Believe it or not, automobiles powered by internal combustion engines originally got the nod over horses for pollution reasons (think excrement). City streets were a mess! However, one form of pollution was in-effect traded for another (one you could see vs. tailpipe emissions that weren’t necessarily visible).
This diagram, which illustrates the breakdown of greenhouse gas emissions within the United States’ economic sector in 2019, is available on the Environmental Protection Agency’s website. As the biggest source of greenhouse gas (GHG) production, it stands to reason why the transportation sector is the current focus. However, once this 29-percent is gone, what will be targeted next, electricity production? It only makes sense that the next GHG polluter on the totem pole is going to be pursued, and that means power plants. Unless we can fully decarbonize electricity production, where will cleaner electricity come from?
But while exhaust pollutants at the tailpipe have virtually been eliminated, it doesn’t mean manufacturers have solely concentrated on PM and NOx reduction. Over the past 20 years, ICE’s and ICE-hybrids have almost exclusively contributed to significant decreases in greenhouse gas emissions. Since the year 2000, CO2 emissions in particular have been reduced by roughly 40-percent. That’s not enough to satisfy coming GHG standards, but it’s proof that CO2 can be reduced, and likely will be further reduced in ICE’s.
While hybrid cars like the Toyota Prius receive a lot of praise for lowering CO2 output, the significant 20-year decline in CO2 emissions wouldn’t have been possible without direct injection engines (both diesel and gasoline) and high-pressure common-rail injection. Smaller displacement engines with more reliance on turbocharging have also greatly aided the effort.
As many readers well know, exhaust aftertreatment systems aboard modern diesels were designed to reduce exhaust pollutants such as PM and NOx. The catch 22 here is that through the process of oxidation using diesel oxidation catalysts (DOC) and diesel particulate filter (DPF) systems, emissions are transformed from harmful CO, UHC, and PM into CO2, which is classified as a greenhouse gas. So did we trade in solving one pollutant at the expense of increasing the amount of CO2 in our atmosphere? As PM and NOx pollutants seemed to be the more immediate threat at the time DOC’s and DPF’s were implemented, it’s possible.
Although many BEV proponents would have you believe that BEV’s are the only way forward in the fight to reduce GHG emissions, there aren’t any silver bullet type solutions. The world is changing, or at least appears to be poised for radical change, but yet there are still no definitive answers or widely-established solutions for curbing GHG. The fact remains that vehicles have to be built before we can drive them…this calls for resources to be extracted from the Earth—a process that has yet to be fully vetted in the case of BEV’s (i.e. environmentally harmful lithium and copper extraction, not to mention the inhuman labor conditions in battery production). Of course, very few are examining the added electricity production a world full of BEV’s will require as well. More on that later.
Much of the media (automotive and general news) and no shortage of politicians would have you believe electric vehicles are the only way forward. But many of them forget or choose to ignore how far diesel (and gasoline) internal combustion engines have come. After all, it’s much easier to criticize and pick apart a technology that’s been established for more than 100 years than one that hasn’t yet been embraced by the masses. Anyone that says diesel hasn’t come a very long way, especially over the last 15 years, is lying to you. Even though we love to hate things such as EGR, DPF, DOC’s and SCR due to their reliability issues and added complexity, thanks to these emissions systems diesels in the U.S. meet the most stringent NOx and PM standards in the world—and they can even be made cleaner yet.
Diesel engines (and ICE’s across the board) have cleaned up their act so much in the way of particulate matter that today—at least in the United Kingdom—the biggest producer of PM isn’t even exhaust-related. Rather, particles from tires, brakes, and road abrasion is the largest contributor to PM. Thanks to improving exhaust aftertreatment technologies, exhaust PM has seen a considerably sharp decline since 2000, while non-exhaust PM has steadily increased—primarily due to increased traffic.
In the words of Felix Leach, co-author of Racing Toward Zero: The Untold Story of Driving Green, “the ICE has changed over more than a century of development into a lower emitting, higher efficiency, higher power, and safer machine than [Nikolaus] Otto or [Rudolf] Diesel could have ever imagined.” With factory diesel trucks closing in on 500 hp, 1,100 lb-ft of torque right off the showroom floor, and burning cleaner than ever before, we would have to agree.
Because today’s diesel engine is so clean, we believe it’s earned the right to co-exist with BEV’s well into the future. After all, even Tesla CEO, Elon Musk, acknowledges that even if all OEM production went electric tomorrow, it would still take roughly 25 years before ICE vehicles were gone from the roadways. So if internal combustion engines will still be around for at least another quarter century, why not continue to improve them?
Advanced combustion strategies such as Reactivity Controlled Compression Ignition (RCCI), where two fuels are used within the combustion chamber can provide amazing fuel efficiency (up to 20-percent improvement over traditional diesel)—and improved fuel efficiency is a simple yet key way to lower CO2 emissions. RCCI calls for port fuel injection of a high octane fuel source (such as gasoline) and direct injection of a fuel that’s high in cetane (diesel). When tested in low compression, over-the-road engines, both NOx and PM were reduced by 87.5 percent and 95 percent, respectively. CO2 decreases of between 20 and 30-percent over convention diesel combustion can be realized with RCCI through oxygen enrichment.
Other optimized injection, combustion, and overall engine strategies that show promise include Premixed Charge Compression Ignition (PCCI) and opposed-piston engine designs. Cummins and other manufacturers have experimented with PCCI in the past, Cummins having even found that a blend of both diesel and gasoline was most desirable with this advanced type of ignition strategy. More precise ignition equals lower fuel consumption, the first (and arguably the easiest) step in lowering GHG output.
It’s a case of teaching an old dog a new trick with a twist, but Achates Power made headlines in 2020 when it brought the century-old two-stroke, opposed-piston diesel design back from the dead, albeit with a few modern tweaks. Its most popular concept engine, a 450hp (1,750 lb-ft) 10.6L intended for the Class 8 market, features three cylinders, six pistons, and boasts a stroke-to-bore ratio of 2.6:1 and is void of a cylinder head—which reduces heat losses tremendously. Incredibly, the Achates Power 10.6L already beats 2027 EPA and CARB CO2 regulations by 8-percent—and that’s without any form of advanced combustion strategy being implemented.
Use of low-cost biofuels is another option at the ready, and is capable of providing significant reductions in greenhouse gases. These carbon-neutral fuels could be produced on a grand scale with oil refiners on board, and most of them don’t require an engine redesign to burn them. To a small degree, this is already being done (on a varying scale) throughout the U.S. in the form of the standard ULSD, biodiesel mixture you fill up with at the pump. Moving away from fossil-derived fuels is the key here.
So with greenhouse gases being the foremost emission target and diesels known to emit fair amounts of CO2, how can compression-ignition exist in the new world? For starters, we could utilize technology that’s already available today: diesel-electric hybrids. A battery pack aboard every diesel could help for more efficient propulsion. After all, even a minimal amount of electrification can help any engine operate in its optimal efficiency range.
Why do we think diesel will co-exist with BEV’s for the foreseeable future? According to the most recent global passenger vehicle fleet outlook prepared by BloombergNEF (a data company that focuses on energy investment), by 2025 more than 1.2 billion of the world’s 1.6 billion vehicles will still either be ICE or hybrid-powered. By 2040, the number of hybrids increases but ICE’s and hybrids will still dominate the passenger vehicle landscape with roughly 1 billion vehicles.
If you buy into the BloombergNEF projections, then it’s easy to conclude that some of the vehicles being built right now will still be around in 2040. Along the same lines, an ICE car or truck built in 2025 or 2030 will have an even better chance of being on the road in 2040—so why not continue to perfect the ICE while simultaneously investing in BEV technologies? Behind the scenes, we think this is what most OEM’s are doing. They know that diesel (as well as gasoline) isn’t going anywhere in the near future.
By solving one problem (tailpipe emissions), BEV’s may be creating a new one: increased electricity production. Power plants account for a quarter of all greenhouse gas emissions in America, and 62-percent of all electricity comes from fossil fuels such as coal and natural gas. Increased demand on the electrical grid means more electricity will have to be produced—and supplemental resources such as wind and solar likely won’t be able to make up the difference on their own. It’s proof that emissions aren’t just a tailpipe problem, as all means of transportation have an effect on the environment. And by the way, despite what many in the automotive media have printed, there are no zero-emission vehicles in production today. Photo Courtesy of David Jolley.
Because no country on Earth has the ability to generate all of its electricity renewably at the present time, we think the race to the bottom (of GHG emissions) should be more of a jog than a sprint. While BEV’s may be a step in the right direction for attempting to curb greenhouse gases, they are far from the smoking gun that will be needed to accomplish this.
While the world goes all-in on electric, even Californians are investing in diesel—mainly in the form of backup generators. In 2020 alone, the backup generator population in the South Coast Air Quality Management District (the greater Los Angeles area) grew by 22-percent. In the state’s Bay Area Air Quality Management District (San Francisco), generator numbers are up 34-percent over the last three years. Both districts combined account for 23,507 backup generators (more than 90-percent of which are diesel powered) and can generate 12.2 gigawatts—roughly 15-percent of California’s entire electric grid.
In a state that is highly familiar with experiencing rolling brownouts, are Californians preparing for more electrical grid instability? Surely as the demand for BEV’s accelerates, so too will the demand for electricity, right? The massive uptick in diesel backup generators in the Golden State may illustrate its residents’ lack of trust in the grid, along with an uncertain future.
To be sure, not all BEV’s are created equal. There is a reason you pay more for a Tesla (the most popular BEV maker in the world), and one of them is the company’s inclusion of battery thermal management in all of its cars. A thermal management keeps the cells from degrading due to fast-charging, but also safeguards against thermal runaway and even fire. However, because of technologies like this (as well as others) the huge difference between the cost of an ICE vehicle and an electric one is oftentimes greater than 50-percent.
BEV’s without active thermal management systems tend to have batteries that degrade much faster than those with active thermal management systems (less energy storage). One example of this is the Nissan LEAF. While the Nissan LEAF is one of the more affordable BEV’s on the market, its lack of this technology may be part of the reason for the lower price tag, but also (and arguably, more importantly) why its range is often cut in half in relatively short order.
Speaking of range, this is one area where BEV’s have made huge gains over the past decade. Recognizing that range was a key point of hesitancy amount prospective buyers, BEV makers have worked long and hard to increase the amount of miles a full charge will take you. As a result of both improved batteries and battery management systems, the average BEV is closing in on 300-mile range as standard equipment, with many capable of going 400, 500, and even 600 miles on a charge. However, with increased range often comes a heftier price tag—and an aging yet strong-running Volkswagen Golf, Jetta, or Passat TDI can easily achieve 600 to 700 miles per tank, and can be filled up in minutes.
At the present time, there are a host of disadvantages associated with BEV’s. Many of them are being addressed and improved upon as we write this, but the fact remains that there are several key sticking points for this means of transportation. First and foremost, cost is still a concern. Granted, the price of the average BEV continues to drop thanks in large part to cheaper batteries becoming available, but the average used Tesla Model 3 (standard range) still sells for well over $40,000. A used Long Range version calls for more than $50,000 currently. That’s reasonable, but these entry level BEV’s are a very far cry from the $14,295 starting MSRP for a Mitsubishi Mirage, for example, a vehicle with a non-hybrid gasoline engine that returns respectable fuel economy.
One aspect of the BEV segment that should be the envy of any diesel or ICE owner is the fact that a BEV can be refueled at home (or rather, recharged). However, the quickest means of recharging a BEV (i.e. DC fast charging stations) calls for some serious juice. Some DC fast charging stations call for 50 to 100 amps. With most American homes fed with 150 to 200-amp service, will homeowners be able to dedicate half of their home’s power to charging their car? Granted, this isn’t the only means of recharging a BEV, but it’s certainly the fastest and most attractive to anyone on the go.
But where do you recharge a BEV publicly? For ICE owners it’s pretty easy considering there are more than 115,000 gas stations in America alone. There are significantly less charging stations (level 2 and DC fast charge) than that, although this part of BEV infrastructure is being expanded upon regularly. In particular, Tesla is leading the charge, with more than 30,000 Supercharger stations globally.
BEV battery packs, electric motors, and other required system components are greatly affected by temperature changes. Both extreme heat (where the A/C is cranked) and especially extreme cold are proven to reduce the effective range of a fully charged BEV substantially. In freezing temps, not only is the range of a BEV reduced between 20 and 30-percent, but charge times are longer, too.
As things stand today, BEV owners unwilling to install DC fast charge stations in their homes (a considerable cost, in addition to paying a premium for the vehicle itself), will have to settle for overnight charge times. For car owners who make several long commutes per day, a BEV makes the most sense as a secondary vehicle. Again, BEV technology is changing quicker than anything else in virtually any other industry right now, so quicker 240-volt charge times or improved access to public fast charging could all change in the coming months and years.
Currently there are three different types of charging for BEV’s: Level 1, Level 2, and the aforementioned DC fast charge. Level 1 charging, which uses 120-volt power, is the slowest method. Level 2 utilizes 240-volt power and can cut charge time by more than 500-percent. DC fast chargers provide direct DC power to a BEV and can fully recharge most battery packs in 1 to 2 hours’ time. For a real-world example, one of Tesla’s publicly available Superchargers can bring a Model S up to 80-percent capacity in 30 minutes.
UNITED STATES DEPARTMENT OF ENERGY
UNITED STATES ENVIRONMENTAL PROTECTION AGENCY