Electric vehicles are growing significantly in market share, up to about 2.5% globally in 2019. However, with EV sales expected to increase significantly in coming years, questions still remain around their functionality in a variety of areas.
For example, until charging networks are as common as gas stations, charging electric passenger vehicles on long trips will continue to be a hassle. Compounding on this issue is the length of time it takes to charge electric vehicles. While supercharging and fast charging are getting faster all the time, it's still not as fast as simply filling up a tank.
Both of these issues, involving time and charging availability, are central in the current debate around which types of commercial vehicles are practical for electrification. The trucking and commercial industries need long-haul vehicles that can fill up fast with ease. Electricity isn't there yet, but Hydrogen fuel cells may be the answer.
Hydrogen fuel cells convert hydrogen gas into electricity onboard the vehicle, releasing it through a chemical reaction in the cells. This allows the vehicles to refuel in a more traditional way — at a pump. This solves one of the problems surrounding electrification, the speed at which vehicles can be filled up.
However, anyone that has been to a gas station lately likely realizes that hydrogen isn't yet available at your neighborhood pump station. However, this problem can be solved more easily than adding electric charging stations, in that, hydrogen is a shippable and storable product, much like traditional petrol. Whereas constructing electric fuel stations requires significant investment in infrastructure.
So, is hydrogen the golden goose of alternative fuels for the trucking industry? Perhaps. But first, we need to understand the technology in greater detail.
What are hydrogen-electric trucks?
Toyota, Honda, Hyundai, and other automakers have all invested in hydrogen fuel cell medium and heavy-duty vehicles. This particular segment of the industry used to be one dominated only by startups with lofty goals (such as the now struggling Nikola), but it now finds itself rife with big investment from legacy automakers.
Fuel cells allow trucks to run on electric motors, benefiting from the instant torque and scarcity of moving parts. They have a relatively long range, and allow trucks to be filled up rapidly, and in a traditional means, at a pumping station. And finally, the only exhaust that exits the vehicles of hydrogen fuel cells is water.
In essence, hydrogen fuel cells make up quite possibly the perfect middle child to bridge fossil fuels and electrified vehicles.
A company by the name of US Hybrid Inc., a California-based company, has been developing fuel cells for heavy-duty trucking applications for some time now. In fact, the company has started licensing and selling their fuel cell engines commercially, to clients like the U.S. Air Force, vehicle startup Faraday Future, and several public transit agencies.
Vehicle startup Nikola Motor Co. is developing the Nikola Two semi, a hydrogen-fuel-cell truck that can produce 1,000 HP, and travel for up to 750 miles (1,207 km) on one tank of hydrogen.
Startups like Nikola also might help advance the adoption of hydrogen fuel cell technology as well, as one of their goals is to develop a hydrogen fueling network across the US, something that is notably lacking today. In fact, most hydrogen vehicles are in use in California because this state has the majority of hydrogen fueling stations in the US. Outside of California, there' one station in Connecticut, and the vast expanse between these two states is more or less devoid of anywhere to fill up on hydrogen.
Toyota is in the development of Project Portal, a class 8 truck that is powered by a hydrogen fuel cell. The truck is being tested in California with the primary goal of using it to shuttle containers between the port and Long Beach, a 70-mile (112 km) journey.
Honda has also recently partnered with Isuzu on fuel-cell development.
With all of these companies investing in the tech, what actually sets hydrogen fuel cells apart and how do they work?
Hydrogen fuel cell engineering
Fuel cells are composed of cathodes, anodes, and an electrolyte membrane. By passing the hydrogen fuel through the anode and oxygen through the cathode, the molecules can be broken down into electrons and protons with the help of a catalyst. The protons then pass through the electrolyte membrane and the electrons are forced through a circuit, which generates a current. On the cathode side; the protons, remaining electrons, and oxygen then combine to create water molecules. This water is the only emission from fuel cell vehicles.
The best part about fuel cells is that there are no moving parts, they operate silently, and they are incredibly reliable. The downside, at least currently, is that the process of converting hydrogen into electricity within a fuel cell is inherently inefficient. Currently, only about 30% to 50% of energy actually makes it to the wheels of a fuel-cell vehicle because of the energy needed to produce the hydrogen.
As for the parts in fuel cell vehicles, the unique components include the fuel cell stack, which is a grouping of electrode membranes that make up the fuel cell. There are also hydrogen fuel tanks that store hydrogen gas for the fuel cell to use. There are several power and thermal control systems required as well. There's the power electronic controller, which manages the flow of electricity from the fuel cell to power the electric motors for the wheels. There's then the thermal system that maintains ideal operating temperatures of the fuel cells and the motor.
Of course, there are also batteries onboard fuel cell vehicles to store excess energy from the fuel cell, along with energy created from regenerative braking.
The biggest thing you might notice about the setup of fuel cells and fuel cell vehicles is the lack of moving parts. Most of the processes that occur in fuel cells are chemical in nature, meaning that there are fewer things in the car that can mechanically break or need repairs compared to traditional internal combustion engine (ICE) vehicles.
Advantages of the technology
We've already gone through several different advantages of hydrogen and how it can serve as a sturdy bridge into the world of electrification, but there's more to the story.
We have gone through this actually but one of the biggest selling points of fuel cells is their emissions, and not just from a strictly-environmental perspective. From a marketing perspective, being able to tell customers that the only emission from their vehicles is pure water is a strong selling point.
Hydrogen fuel cells also work in extreme conditions, even in very cold environments, a place where battery-only vehicles struggle.
The efficiency of hydrogen fuel cells is around 30 to 50 percent, according to the U.S. Department of Energy, which is significantly worse than battery-powered cars, which are 70-80% efficient. These efficiencies are measures of how much of the potential energy in a fuel the engine or cell is able to convert into usable power.
Scalability is also being debated. Because there's already a gasoline fuel station every few miles globally, there's already infrastructure in place that can be adapted for hydrogen. However, installing hydrogen fuel cell infrastructure nationally could expensive compared to the expansion of the EV charging infrastructure, mainly because there is already an electrical grid in place in most areas. It is also possible to charge EV vehicles from home, whereas hydrogen cells would require a trip to a recharging station.
Hydrogen fuel cells themselves, being quite adaptable, do allow for a variety of use cases, from small vehicles to large ones. A small hydrogen fuel cell for use in a lawnmower has the same basic operation as a larger one that would be used in a semi truck.
So, why isn't hydrogen more popular? The answer to that is multi-pronged. Currently, the vast majority of hydrogen produced in the United States occurs through the process of steam reforming. This process utilizes natural gas to produce hydrogen, and that's a fossil fuel. The hydrogen fuel would also need to be transported to the pumping stations. So in essence, hydrogen fuel cell vehicles right now just offload their carbon output to the hydrogen manufacturing and transport process.
There are ways to produce green hydrogen, through the process of electrolysis, which breaks water down into its base elements (oxygen and hydrogen) utilizing an electric current. If this current is supplied by renewables, the hydrogen produced becomes quite green. However, this process isn't as scalable, due to the lack of renewable proliferation on a wide scale in the US and it's also not as cost-effective, making the fuel more expensive to purchase.
Hydrogen as it currently stands, comes from predominately non-green sources, is about 50 percent more expensive than gasoline, making it a more expensive option. It's this non-green origin of hydrogen and the cost that keeps it from becoming widely adopted, but the fundamentals are there.