In terms of how they drive, fuel cell electric vehicles, sometimes abbreviated as FCEVs, work exactly like regular battery-powered electric vehicles (BEVs). Electric motors provide power to the wheels and there’s no internal combustion engine. But while BEVs are charged by external power stations, FCEVs bring their powerplant with them, a hydrogen fuel cell.
Honda, Hyundai and Toyota now offer practical FCEVs to buy or lease, but they’re still an emerging technology and generally only available in California thanks to the Golden State’s embrace of green technologies. That said, automakers are committed to expanding both the availability of hydrogen power and the array of vehicles that use it, so more FCEVs are in the pipeline.
How Does a Hydrogen Fuel Cell Vehicle Work?
“Fuel cell” is actually a misnomer. In reality, every FCEVs uses several hundred fuel cells. Individually they don’t produce much power, so a large number are combined into what is called a “stack.”
Inside the fuel cell stack, compressed hydrogen gas and oxygen are passed through an electrochemical catalyst. The catalyst in each cell strips the electrons from the hydrogen atoms. The electrons are collected in the stack and released to flow through appropriate wiring to power the vehicle’s electric motor. A small lithium-ion battery stores any excess power it until it is needed–for a quick burst of acceleration when passing, for instance.
Combining hydrogen and oxygen forms water, which is used to cool the fuel cell stack–exciting all those atoms so they’ll free their electrons heats things up quite a bit. Most of the water turns to steam and a thin trickle of water and wisps of water vapor are the system’s only emissions.
Hydrogen isn’t the only fuel source that can be used this way, but it’s become the energy carrier of choice because it is easy to strip of its electrons and is the most common element on the planet.
It rarely exists in pure form, however. Most hydrogen used in the U.S. is produced by breaking down natural gas, a process that requires lots of electrical power and produces substantial amounts of greenhouse gases.
Numerous studies by independent groups and agencies including the Argonne National Laboratory, have shown, though, that the environmental impact of producing and using hydrogen for fuel cell vehicles, while greater than using grid electricity to power battery EVs, is less damaging than producing and burning fossil fuels. Hydrogen can also be produced using greener methods such as wind and solar power or breaking down plant materials; they just require more time or cost.
It sounds like an ideal low-emissions power source, but the reality of it is a little more difficult. Hydrogen is a powerful element, but is also infamously volatile, hard to store, and expensive to produce.
The History of Fuel Cell Vehicles
Fuel cell technology has been kicking around since English inventor Sir William Grove built the first working hydrogen cell in 1842. It took generations of development in electronics and battery science to bring it to the automobile, in part because of questions about how to do it safely.
In 1966, General Motors built the first proper fuel cell-powered passenger vehicle, the GM Electrovan. Based on a full-size passenger van, it had only two seats, because the fuel cell system took up almost the entire passenger area. That project was abandoned because of cost, complexity and the lack of an available fuel supply.
Automakers didn’t return to the idea of hydrogen power again until the early 1990s, with BMW leading the charge.
Instead of a fuel-cell electric vehicle, the German firm tried burning liquefied hydrogen like gasoline in a beefed-up regular internal combustion engine, a V-12. After a decade of trying with these modified 7 Series sedans, this experiment was also abandoned. Liquid hydrogen just didn’t pack gasoline’s punch–those V-12s performed more like anemic V-8s.
Liquefying hydrogen also underlined just how difficult it might be to support such vehicles in the real world. It requires enormously expensive cryogenic freezers and storage tanks as well as automated filling systems to protect drivers from coming in contact with the fuel. At minus 423 degrees Fahrenheit, liquid hydrogen will freeze and destroy almost anything organic.
The rest of the industry has concentrated on the hydrogen fuel cell approach. The still-active California Fuel Cell Partnership was formed in 1999 as to facilitate testing and development of FCEVs and most major automakers have been a part of it at one time or another but to date only three have brought fuel cell models to market.
After experimenting with the diminutive Honda FCX from 2002 to 2007, which was not widely available to regular consumers, the automaker launched the original Clarity FCEV in 2008. It too was built only in tiny numbers, with just 48 reaching U.S. roads that year, all leased. Hyundai introduced its fuel cell Tucson SUV in 2014, Toyota launched the Mirai fuel cell sedan in 2016 and Honda brought the second-generation Clarity FCEV to market in 2017. Hyundai replaced the Tucson FCEV with the Nexo crossover in 2020, and at the same time Toyota debuted an all-new second-generation Mirai. Honda has just announced that it will not continue the Clarity FCEV in 2022.
While all of today’s fuel cell vehicles are considered mass-market production cars, none are available outside of California and the Honda has never been sold, only leased.
Because their powerplants are so specialized, FCEVs are much costlier to build than regular gas-powered cars. Honda dovetailed the current Clarity FCEV with plug-in hybrid (PHEV) and fully-electric versions to improve economies of scale and make the cars less expensive for consumers, though it has since stopped building the fully-electric version and is discontinuing all versions of the Clarity this year.
Practical Challenges
The vehicles’ cost is one factor in their limited popularity, but the main reason for such limited availability is the scarcity of hydrogen fueling stations to keep them running. There were 47 public hydrogen stations in the U.S. as 2021 began and all but two, one each in Connecticut and Hawaii, are located in California.
Because there’s so little market for it and because most of it is shipped and stored on site rather than being produced as needed, the economies of scale on producing hydrogen fuel aren’t there yet. The current cost of hydrogen fuel is quite high–around $16 for a kilogram, the equivalent of a gallon of gasoline.
For use as a fuel source, hydrogen gas is compressed, usually at 10,000 psi, and chilled before being pumped into a vehicle’s carbon-fiber reinforced fuel tanks. Today’s hydrogen dispensers look a lot like traditional gasoline pumps–except for the thick filler hose and special nozzle that creates an airtight seal when locked onto the vehicle’s fuel intake.
The fuel cell cars available today cover two to three times the distance per gallon-equivalent that their gasoline-swilling counterparts can manage, however, and the cost of hydrogen fuel is expected to fall if demand increases.
That’s likely to happen because while fuel cells are still struggling to make inroads in the passenger vehicle arena, they have been adopted as a viable power system for long-haul commercial trucks. Fuel cell truck makers including Hyundai and start- up Nikola Motors say they have orders for several thousand.
In the 1960s, Diesel fuel was found mainly at truck stops, but as commercial trucking switched over to diesel, its availability became widespread. The same may happen with hydrogen.
