Toyota Motor Corp. has big hopes for its fuel cell technology — the zero-emission powertrain has already been used in a futuristic passenger sedan, is being adapted for heavy commercial trucks and could potentially be applied to just about every vehicle in between.
But if hydrogen isn’t readily available, all of that is useless.
It’s a technical and logistical double-whammy that bedevils any innovator hoping to scale up hydrogen fuel cell use in vehicles. Not only must the hydrogen be laboriously converted for use as a fuel, customers can’t get to it unless some sort of delivery infrastructure is in place.
“If Toyota is going to do this, it will have to invest in getting the [hydrogen] fuel out there and to do whatever else is needed to make it more user friendly,” said Lisa Jerram, a transportation analyst and fuel cell specialist with Navigant Research.
That will be one of the key challenges as Toyota develops Project Portal, its fuel cell semi-truck.
Where to Get It
Hydrogen is the most plentiful element on the planet. But with automakers only beginning to adopt the technology, hydrogen fueling stations in the U.S. amount to just dozens.
The federal Department of Energy’s alternative fuels center counts just 36 public hydrogen stations, most of them in California. Even including all privately owned, government-owned and planned stations, the total still falls under 100.
The vast center of the country is almost entirely devoid of hydrogen stations.
Truckers with diesel rigs, by comparison, have tens of thousands of stations from which to choose. More than half the 120,000 service stations in the U.S. provide diesel, according to the Diesel Technology Forum. That number includes truck stops and convenience stores as well as neighborhood Chevron or Shell outlets. Additionally, most trucking companies and freight yards have private diesel fueling facilities.
Toyota has offered financing help to get some public hydrogen stations built, hoping to expand the marketplace for its Mirai sedan. But the company wants to avoid paying for hydrogen stations for commercial trucks, said Craig Scott, senior manager of advanced market planning at Toyota North America.
Fuel cell passenger cars sell in such small volumes that revenues from hydrogen sales don’t yet justify the nearly $2 million investment required to build a small retail station without help from the automakers. Toyota believes that if it can make the economic case for fuel-cell trucks compared to diesel trucks, market forces will drive private development of fueling stations to serve them, Scott said.
Evidence of demand is growing. Late last year, Utah-based Nikola Motors announced plans to develop a long-haul tractor with a hydrogen fuel cell system capable of delivering the equivalent of 15 mpg, with the first prototype due in 2019. Nikola also intends to build a web of fueling stations.
“I can tell you that in visiting fleets, and I’ve been to 50 or so [since the Nikola announcement], there is more buzz over this than I ever saw with fuels like CNG or LNG,” said Steve Zerphey, senior manager of fleet maintenance programs consulting for Master Fleet National.
The first fuel cell trucks will likely be short-haul drayage trucks based in or around ports and freight terminals, like the pilot vehicle Toyota is testing. They’ll need privately owned and centrally located hydrogen stations where they can fuel overnight or in between daytime runs, according to Sheldon Brown, a Toyota fuel cell program engineer.
But if fuel cell technology migrates to longer-haul commercial and work trucks, hydrogen truck stops will need to start popping up on or near highways.
Without them, fuel cell vehicles — and the technological ambition powering them — will have nowhere to go. But it’s not hard to refine hydrogen into fuel.
In nature, hydrogen atoms are bound to other atoms. Water, for example, has two atoms of hydrogen bonded to a single oxygen atom.
Fossil fuels are just combinations of hydrogen and carbon — or hydrocarbons. The methane in natural gas, the most common source of the 9 million tons of commercially produced hydrogen annually consists of one carbon atom and four hydrogen atoms.
But for a fuel cell propulsion system to work, the hydrogen needs to be isolated. It’s a process that requires a tremendous amount of energy.
Hydrogen is stripped from water through an effort called electrolysis. When the element is pulled from natural gas, the process is called steam reforming.
Although commonly called a fuel, hydrogen in fuel cell vehicles is only an energy carrier. The hydrogen releases its electrons in the presence of a catalyst, and the resulting electricity is the fuel that powers the vehicle’s electric motor.
On a source-to-wheels basis, vehicles that use fuel cell systems are generally more energy efficient than those relying on gasoline or diesel, according the Department of Energy’s widely used GREET (Greenhouse gases, Regulated Emissions and Energy use in Transportation) modeling tool.
Toyota, which isn’t in the business of making hydrogen, buys it from companies — such as Air Liquide, Praxair and Shell Hydrogen — that specialize in industrial gases and gaseous fuels. Toyota senior fuel cell engineer Takehito Yokoo said the company’s testing and computer modeling show that a zero-emission fuel cell electric truck should be almost twice as efficient as a diesel truck in converting its fuel to energy.
Hydrogen is much easier to ignite than gasoline and diesel. But it also is 14 times lighter than air, so its vapors don’t collect and pool like those of petroleum fuels.
In the event of a collision, hydrogen gas that seeps from a punctured tank could quickly escape into the atmosphere, sped along by intense pressurization of roughly 10,000 pounds per square inch.
Toyota is trying to head off flammability concerns with a suite of rather aggressive tests.
The Toyota fuel cell Mirai sedan features a plastic tank reinforced with carbon fiber. During development, engineers would toss the filled tanks into blazing flames or puncture them with ammunition fired from high-powered rifles.
The fuel cell truck is facing similar abuse.
“We didn’t use the bullet test for the truck tanks, but we did use the bonfire test,” Yokoo said.
Both the truck tanks and the car tanks emerged from the tests without exploding or melting. An unrelated 2008 research project at the University of Miami (Fla.) suggests why.
When a fuel tank is pierced and the hydrogen is lighted, the flaming gas shoots straight up and away from the hole — like the flame from a butane lighter, university researchers found. Igniting a leaking gasoline tank on one test vehicle led to its quick destruction by fire, while lighting a leaking hydrogen tank on another caused almost no damage, the Florida test showed.