Powertrain electrification is becoming the new standard for the automotive and commercial industries. The passenger car market is primarily meeting the demand for lower emissions through battery electric vehicles (BEV) like the new Audi e-tron and Hyundai Kona. Alternative powertrain options are also coming for the heavy-duty market. Unlike light-duty vehicles, the diesel-reliant trucking industry is focusing on hydrogen fuel cells as the primary powertrain replacement.
Despite each market’s seemingly disparate approach to zero emission options, hydrogen fuel cell electric vehicles (FCEV) have analogous powertrains to BEVs. Both leverage batteries to power electric motors driving the wheels. However, the difference remains in the source of recharging the cells. BEVs require an external energy source for recharging power while hydrogen fuel cells utilize the fuel on the vehicle. This duality in power sources is not new to the mobility industry and is recognized as a necessity moving forward.
Image Courtesy: Nikola Motors
Nikola Motors CEO Trevor Milton acknowledged this connectedness between BEVs and FCEVs at their Nikola World 2019 conference. “We knew that if we were going to be successful as a company, we could not be completely biased. Our agenda is not hydrogen or battery electric. We believe hydrogen is an incredible fuel. We believe storing energy in batteries is a great thing. Every one has its own market. Not one size fits all. We wanted to make sure when we went into fleet, we understand your supply chain.”
Dual fuel history
Vehicle powertrains have a history with multiple power sources. The passenger car industry remains 98% gasoline-powered today. The heavy vehicle market has similarly been reliant on diesel-based powertrains. There has been some crossover with diesel engines in light-duty vehicles and gasoline in heavy-duty applications, but there remains a strong disparity between markets and power sources.
That duality may continue as powertrain alternatives are developed to contest tightening emissions regulations and vehicle restrictions. Electrification efforts are proliferating the passenger car market toward BEVs. However, fully electric heavy-duty trucks have garnered far less development. Tesla has announced the Semi electric truck. Other than smaller, local electric trucks, the rest of the heavy vehicle market is focused on hydrogen fuel cell powertrains.
In 2017, Toyota launched Project Portal as a feasibility study for fuel cell technology in heavy-duty use at the Port of Los Angeles. In 2018, Toyota furthered their commitment to hydrogen fuel cell use with Project Portal 2.0 and a second generation Class 8 truck. This year, Kenworth announced a Class 8 T680 fuel cell electric truck (FCET) jointly developed with Toyota. Nikola has released three FCET in sleeper cab and day cab configurations to meet the needs of various heavy vehicle customers.
Usage profiles drive fuel options
The leading factor behind the use of multiple fuel or power sources is the difference in usage profiles between automobiles and commercial vehicles. A passenger car is expected to last 150,000-200,000 miles (240,000-320,000 km) whereas a Class 8 truck is expected to travel 1,000,000 miles (1,600,000 km) over its lifetime. The truck’s extensive travel is primarily highway use as opposed to local driving for automobiles.
Image Courtesy: Toyota
A fully electric long-haul truck would have significant restrictions due to the battery pack size and weight necessary for this application. These issues were noted by Tak Yokoo, Senior Engineer for Toyota NA R&D, at the launch of Project Portal. “Instead of having a large and heavy battery, which basically takes over the cargo space and cargo total weight, a fuel cell becomes a more optimized application.”
Hydrogen fuel cell powertrains provide significant weight and space saving advantages over battery electric ones for heavy-duty trucks. This allows for similar packaging to current trucks and minimal design alterations for the new power source. While there have been significant gains in development of FCET, there remain implementation hurdles for the technology to expand and meet trucking needs.
Goals for future hydrogen expansion
The primary challenge for hydrogen is the refueling infrastructure. There are a few refueling stations on the coasts, but not nearly enough to support long haul travel requirements. Nikola Motors has announced its goal of providing 700 refueling stations by 2028 with a Memorandum of Understanding with Air Liquide, Hyundai, NEL, Shell, and Toyota to test pre-commercial 70MPa hydrogen heavy duty vehicle high flow (H70HF) fueling hardware for future Class 8 trucks. TÜV SÜD is also working to expand hydrogen stations in Europe to meet global demands for this growing alternative.
Image Courtesy: Nikola Motors
Another area of development to assist refueling expansion is standardization. “Recently, Standards for hydrogen vehicles have focused on fast fueling/charging and safety,” said Jesse Schneider, Vice President of Hydrogen and Fuel Cell Technologies at Nikola. “Both of those topics are really very well developed for the light-duty vehicle. The next goals are to find the same thing for heavy-duty. I think heavy-duty is going to follow a lot of what the SAE standards together with the Global Technical Regulations have done. Fueling HD is the next frontier for standardization.”
As these infrastructure and standardization needs are met, hydrogen can become a viable powertrain option for long haul trucking. The heavy-duty market may be looking at a different power source than automotive, but the goal is common between them: a zero-emission future.
Purchase the latest book on hydrogen fuel cell vehicles, “Impacting the Commercialization of Rapid Hydrogen Fuel Cell Electric Vehicles (FCEV)” by David Wood.
Visit SAE.org/standards/development for more information on developing commercial vehicle standards at SAE.
Attend COMVEC 2019 for more information on the latest commercial vehicle research and advancements.
Matthew Borst is a content editor at SAE International in the Global Products Group. Previously, he worked as a technical writer at Polaris Industries and was responsible for writing service manuals for various powersports products. He graduated from Minnesota State University, Mankato with a degree in Automotive Engineering. His interests include the latest automotive industry news, movies, hockey, and anything that keeps his two kids entertained.
Contact him regarding any article or collaboration ideas by e-mail at firstname.lastname@example.org.