You may think a volt is just a volt, especially when it comes to a hydrogen fuel cell or lithium-ion battery. And while that is certainly true from a physics standpoint, when it comes to how an electric drive motor powers an electric truck, it doesn’t care where that volt comes from. Yet, the stakes for electric trucks are much higher than a simple matter of where the volts come from. And that is where the debate rages. On one side you have those in favor of battery-electric power and on the other those in favor of fuel cells. Will a clear winner emerge?
Why Electric Trucks?
A lot of talk has been around Tesla and other company’s attempts to build an electric Class 8 semi. While the tesla glitterati out there would love to see the company take on more and smash their competition, there are some hard realities to consider. Some big players in trucking simply are not convinced that there is a value proposition for electric big rigs, with Daimler being the biggest naysayer.
Still, the biggest difference here is that many of the large truck OEMs have been trying to adapt legacy diesel models to become electric vehicles. Tesla, Nikola, and others getting in on the trucking game are building their platforms around electrification, rather than adapting them to it. Because of this, these companies will be able to better optimize their costs in the short term. A lot of extra cost would have to be eliminated for legacy OEMs to see the same benefit.
Some actively wonder whether there is any reason to be confident that Tesla will succeed in the trucking marketplace. Trucking companies are not the types of companies who will spend a premium on a semi just to burnish their green credentials. The only shade of green that matters to them is the green of the dollar bill.
Another major question lies in the engineering. Traditional OEMs have many, many decades under their belt learning how to build robust, fuel-efficient commercial motor vehicles. New companies to the game may be putting miles on through testing, but their platforms are not yet proven. Is a flashy and efficient truck enough to make a difference to hardened motor carriers used to a certain type of vehicle?
The obvious reason to migrate to electric trucks is for greater fuel efficiency. Yet, should that be the only reason? And furthermore, what is the best method of electrification? Who will eventually win out on the battery versus fuel cell war?
The Benefits of Hydrogen Fuel Cells
So, let’s talk about the different forms of electrification that will find their way onto a big rig. The first is hydrogen. While hydrogen power systems are not as ubiquitous as fuel cell power systems, there are three different variants in development. Nikola, Toyota, and a Canadian consortium are all working on hydrogen-based electric truck systems. Even the skeptical Daimler is participating in the Canadian program.
Hydrogen does have two clear advantages over battery-electric vehicles, with the first being a longer range. You can drive a hydrogen-powered vehicle longer distances without having to make any payload sacrifices. Nikola claims that its purpose-built hydrogen truck will have a 500-800-mile range on just 80 kg of hydrogen. The chassis it rides in should be no larger than a standard diesel variant, it will just be set up differently.
Meanwhile, Toyota, in partnership with Kenworth, unveiled their prototype hydrogen trucks at this year’s Consumer Electronics Show in Las Vegas, and they claim their vehicle will have around 350 miles worth of range, but that the range can be extended depending on how much hydrogen storage capacity they add to the vehicle. Toyota claims that a typical regional haul of around 350 miles should use approximately 120 pounds of hydrogen.
Since all these trucks will not have a diesel engine, transmission, or aftertreatment systems, there should be no problem with adding six carbon fiber hydrogen tanks, a fuel cell stack, and a 12-kW drive battery. In other words, the weight-neutral ratio for hydrogen fuel cell trucks should be comparable to the ratio of standard diesel variants.
The heaviest part of a hydrogen fuel cell drive system are the storage tanks. When full, these tanks can run in excess of 4,000 pounds. Still, that is far less than the weight you would need for lithium-ion batteries to take you the same distance. In that case you would be looking at nearly 16,000 pounds of batteries. Another advantage to hydrogen fuel cells is the lack of charging time. With battery-powered trucks, you may have to wait several hours, whereas filling up your hydrogen tanks should take around 15 minutes.
Fuel cells are a lot like diesel engines in that they operate at their highest level of efficiency when they are running at a steady rate. While the hydrogen flow can be controlled, the battery provides the “throttle” modulation as power is needed for hills or headwinds.
The Advantages of Battery Power
Battery-powered trucks, on the other hand, benefit greatly from stop-and-go operations. For vehicles operating in urban environments, regenerative breaking offers a tangible benefit. Any opportunity to add charge to the batteries is one that should be taken. In fact, according to some studies, regenerative breaking can add up to 50% additional power to the vehicle.
Most of the time, fleets running electric vehicles only operate within 100 – 150 miles per day. So, battery specs that cover a 230-mile range would be just fine for customers who aren’t in the long-haul business. Freightliner’s hybrid eCascadia Class 8 tractors come installed with a 550-kWh battery pack offering 250 miles of range.
Still, the elephant in the trucking OEM room is Tesla, who offers a 500-mile range semi. As a result, big truck OEMs are taking note. Trucking companies serious about getting in on the electric game need to build vehicles that provide a real return on investment for their customers. The only way to prevent defectors back to diesel is to offer solid, quality products.
Trucking OEM Peterbilt has identified three specific markets it believes are ripe for truck electrification. As a result, they are moving forward with medium-duty rigs that run on battery-electric power. Yet, their efforts are not without roadblocks. Since it can take up to eight hours to fully charge a battery pack, trucking companies need to be strategic about how and when they charge their trucks.
And as we reported on before, electric truck charging infrastructure is still in its infancy. We are in the early days of an electric grid that can even handle the pressure. While truck makers and trucking companies are working with utility companies to change this paradigm, it will require substantial commitment from all players. Certainly, battery-powered trucks offered on a mass scale are still a way away.
This is All New Ground
Hydrogen fuel cell stacks are new to trucking. Nikola started with their own clean-sheet proprietary design and it certainly took a long time to even get to a working prototype. Many OEMs are currently struggling with the fundamental question of whether they should also start with a clean-sheet design or adapt their current models. Indeed, many are adapting current models, as that is the path of least resistance. Whether this is the best method remains to be seen.
Another area of unknowns is how companies will pay for all this. While many of the EV pricing numbers that have come out recently are certainly eye-popping, battery prices have been falling. Certainly, when all the dust settles electric big rigs will not be as expensive as they once were or even are today. And as battery production increases, prices are bound to fall even more.
If the industry even makes it to 30,000 electric trucks per year in production, the demand in raw materials and production could cause price increases. Still, as the industry scales, we are likely to see a continuation of small-scale price drops. Most analysts expect the market for 100- to 300-mile range trucks to come in around $150,000 to $200,000 per vehicle with no subsidies, which is not that far off from where we are today.
Fortunately, as governments try to spur adoption of these technologies, subsidies will help trucking companies get in on the game. California is one such example. And as chassis integration evolves, electric trucks will become lighter and even more fuel efficient. Wheel-end motors could eventually completely replace drive shafts and differential axles.
The fact is, the business model for electric trucks becomes clearer by the day. And as trucking companies try to squeeze more and more out fuel efficiency and business operation efficiency, there will come a time when electric trucks simply make sense, no matter how they are powered. And especially when they are competitively prices.