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HydroGENeration - The Generation Gap

A compilation of various blog posts from across the web.


How Do Fuel Cell Electric Vehicles Work Using Hydrogen?

Like all-electric vehicles, fuel cell electric vehicles (FCEVs) use electricity to power an electric motor. In contrast to other electric vehicles, FCEVs produce electricity using a fuel cell powered by hydrogen, rather than drawing electricity from only a battery. During the vehicle design process, the vehicle manufacturer defines the power of the vehicle by the size of the electric motor(s) that receives electric power from the appropriately sized fuel cell and battery combination. Although automakers could design an FCEV with plug-in capabilities to charge the battery, most FCEVs today use the battery for recapturing braking energy, providing extra power during short acceleration events, and to smooth out the power delivered from the fuel cell with the option to idle or turn off the fuel cell during low power needs. The amount of energy stored onboard is determined by the size of the hydrogen fuel tank. This is different from an all-electric vehicle, where the amount of power and energy available are both closely related to the battery's size. Learn more about fuel cell electric vehicles.

High-res image

Key Components of a Hydrogen Fuel Cell Electric Car

Battery (auxiliary): In an electric drive vehicle, the low-voltage auxiliary battery provides electricity to start the car before the traction battery is engaged; it also powers vehicle accessories.

Battery pack: This high-voltage battery stores energy generated from regenerative braking and provides supplemental power to the electric traction motor.

DC/DC converter: This device converts higher-voltage DC power from the traction battery pack to the lower-voltage DC power needed to run vehicle accessories and recharge the auxiliary battery.

Electric traction motor (FCEV): Using power from the fuel cell and the traction battery pack, this motor drives the vehicle's wheels. Some vehicles use motor generators that perform both the drive and regeneration functions.

Fuel cell stack: An assembly of individual membrane electrodes that use hydrogen and oxygen to produce electricity.

Fuel filler: A nozzle from a fuel dispenser attaches to the receptacle on the vehicle to fill the tank.

Fuel tank (hydrogen): Stores hydrogen gas onboard the vehicle until it's needed by the fuel cell.

Power electronics controller (FCEV): This unit manages the flow of electrical energy delivered by the fuel cell and the traction battery, controlling the speed of the electric traction motor and the torque it produces.

Thermal system (cooling) - (FCEV): This system maintains a proper operating temperature range of the fuel cell, electric motor, power electronics, and other components.

Transmission (electric): The transmission transfers mechanical power from the electric traction motor to drive the wheels.


Chuck Hayes, Principal Applications Engineer for Clean Energy, Swagelok

There is no doubt that the economy for hydrogen fuel cell vehicles and fueling is growing. But as the technology gains more prominence, misinformation can become common. For hydrogen, these misperceptions typically revolve around its safety, viability as a mobility fuel, cost, and environmental impact.

Hydrogen has the potential to meet modern vehicle fueling needs, providing safety, reliability, cost-effectiveness, and environmental-friendliness. And, hydrogen could very well be the right, best path forward for the global economy as the world focuses on achieving a greener and more sustainable future for the planet.

Check out an infographic version of this article for a downloadable visual that is easily shared to dispel hydrogen myths.

Here are four common myths about hydrogen worth reconsidering, as well as related facts about hydrogen's viability as a fuel source.

Jump to:

Myth: Hydrogen Gas is Hazardous to Use or Store

Myth: Hydrogen Vehicles are Not a Practical Long-Range Solution

Myth: Hydrogen is Not Environmentally Friendly or Sustainable


Myth: Hydrogen Gas is Hazardous to Use or Store

Hydrogen presents the same, if not fewer, hazards than other fuels due to its nontoxic and low-volatility characteristics. Additionally, numerous safety procedures and protocols are considered throughout each design stage of both hydrogen vehicles and hydrogen refueling infrastructure to enable safe and reliable performance. And when handled properly, hydrogen fueling technology provides an efficient and economical solution for modern mobility needs.

Fact: Hydrogen is 14 times lighter than air and 57 times lighter than gasoline vapor. It will typically rise and disperse rapidly when leaked, greatly reducing the risk of ignition at ground level.

Relative Vapor Density




Fact: Hydrogen is nontoxic, unlike conventional fuels. A hydrogen leak or spill will not contaminate the environment or threaten the health of humans or wildlife, as fossil fuels can.

Fact: The air around the flame of hydrogen is not as hot as around a gasoline flame. Therefore, the risk of a secondary fire is lower.

Fact: While hydrogen can be explosive with oxygen concentrations between 18% and 59%, gasoline can be explosive at oxygen concentrations between 1% and 3%. Meanwhile, gasoline has an autoignition temperature of 536°F (280°C), which is half that of H2 (995°F/535°C).


Autoignition Temperatures



Fact: Vehicles with pressurized gas storage tanks are not new. There is an existing global multibillion-dollar industry that has been making and transporting hydrogen for many decades.

Fact: Hydrogen fueling dispensers are designed to run multiple safety checks in both the dispensing equipment and the vehicle during the fueling process (start, midpoint, end).

Fact: There are multiple international certification programs that review hydrogen's safety as a mobility fuel. For example, Toyota has received approval from Japan’s Ministry of Economy, Trade, and Industry (METI) to self-inspect and manufacture hydrogen tanks for FCEVs.

Fact: Country-specific hydrogen fueling station codes have been developed in 22 countries and include CSA (Canadian Standards), ISO (International Organization for Standardization), and EN (European Standards).

Myth: Hydrogen Vehicles are Not a Practical Long-Range Solution

Range is a common concern for any budding transportation fueling technology—but it shouldn’t be for hydrogen.

Because it maintains high energy density and it is particularly well-suited to heavy-duty vehicle applications, hydrogen's lighter weight can also help to maximize a heavy-duty truck’s payload volume, thereby increasing its range. Plus, high-speed refueling of hydrogen-powered vehicles is also possible, which helps to reduce the downtimes of vehicle fleets and equipment, fueling vehicles in minutes as opposed to hours for battery electric options. And while green hydrogen generation depends on wind, solar, and water—improved storage technologies can keep the clean energy flowing, regardless of the weather. 


Hydrogen Fuel Cell Vehicle

Range: 200 to 250 Miles with 350 bar

400 to 500 Miles with 700 bar

Time to Refuel: 3 to 4 Minutes


Electric Vehicle

Range: 100 to 310 Miles

Time to Refuel: 30 Minutes to 12 Hours


Gasoline Vehicle

Range: 300 to 400 Miles

Time to Refuel: 2 to 3 Minutes


Fact: Hydrogen has high energy density and therefore can deliver a comparable range to carbon-based fuels. Under pressure, it can also be stored and distributed as efficiently as these fuels.

 Fact: While it is the most abundant element in the universe, hydrogen needs to be extracted from water or organic compounds. Diesel and gasoline also requires refining and cleaning of crude oil, however—and this process can also use hydrogen.

Fact:The major source of hydrogen today is extraction from natural gas (which is already a multibillion-dollar global industry).

Fact: Other hydrogen sources include renewables like solar, wind, or biogas. These energy sources power electrolysis, a process which uses electricity to separate water into useful hydrogen and oxygen.

Fact: Hydrogen refueling equipment can be added to existing fueling infrastructure and deliver comparable refueling times to gasoline and diesel.





Myth: Hydrogen is Too Expensive

While conventional fuel remains cheaper today, the price of green hydrogen continues to fall. This price reduction is projected to accelerate over the next decade, making hydrogen truly comparable in price to other mobility fuel sources. Meanwhile, it is expected that government support will accelerate the growth of hydrogen at scale as CO2 emissions standards become stricter. Additionally, the cost and efficiency of renewable (solar, wind, water, etc.) energy resources continue to improve; it is anticipated this trend will extend to hydrogen fuel costs.  

Total Cost of Ownership/USD per 100km



Fact: Major government initiatives, like the U.S. Department of Energy’s (DOE’s) Earthshots program, are intended to spur development and bring down hydrogen costs.

Fact: High-quality fuel system components reduce the occurrence and cost of unexpected maintenance.

Myth: Hydrogen is Not Environmentally Friendly or Sustainable

A common concern around hydrogen’s sustainability involves its production. But there are several ways to generate hydrogen, and most of them are more environmentally friendly than comparable fossil fuels. Plus, hydrogen use in a fuel cell creates no vehicle emissions except water—which will help to dramatically slash greenhouse gas generation globally.


Fact: Using hydrogen in a fuel cell creates no smoke or waste, and the only outputs are energy and pure water.

Fact: There are several processes by which hydrogen is produced, and most of these processes have reduced CO2 emissions.


Grey Hydrogen

Blue Hydrogen

Green Hydrogen

CO2 emitted while reforming fossil fuel (natural gas)

Capturing and storing CO2

Net zero emissions of

CO2 (ultimate goal)



Fact: Carbon capture technology offers a way to sequester carbon and permanently store it (or use it) for industrial purposes.

Fact: Government efforts, such as the DOE's Earthshots program, are anticipated to support and promote long-term growth.

Hydrogen has the potential to reshape the transportation economy as we know it. As sustainability continues to grow as a global priority, hydrogen is the most viable energy solution available for transportation use. The keys to its continued adoption are safe, reliable hydrogen vehicle and refueling systems that OEMs and other stakeholders can rely on now and depend on for the years to come.

If you’re looking for components, services, and training for developing high-quality hydrogen systems, we can help. Swagelok has been providing solutions for the alternative fuel and transportation industry for many years, with products and assemblies designed specifically to help contain, store, and dispense hydrogen for mobility. Our specialists are ready to assist with your needs.


As electric cars have yet to become the norm, should we look at alternative fuels instead?

Green hydrogen has emerged as a promising alternative fuel in our ceaseless quest for sustainable energy sources. But is it really going to transform how we power our eco-friendly vehicles?

What is green hydrogen?

Produced by splitting water into its two components — hydrogen and oxygen — green hydrogen is an intriguing green energy. Unlike gray and blue hydrogen, which are derived from fossil fuels and natural gas, green hydrogen leaves virtually no carbon footprint when produced using renewable energy, such as wind turbines.

To create enough power to propel a vehicle, hydrogen fuel cells combine hydrogen stored in a high-pressure tank with oxygen from the ambient air, producing electricity. This electricity then powers the car's electric motor.


The clean energy contender

Electric vehicles (EVs) are currently the frontrunner in the automotive industry, offering zero-emission transportation and increasingly competitive performance and range. But they're not without their limitations. EVs can face lengthy charging times, limited payload capacities, and the environmental cost of manufacturing batteries.

And while they don't produce tailpipe emissions, electric vehicles still indirectly contribute to greenhouse gas emissions due to the electricity they consume. And if that electricity comes from fossil fuels, the environmental benefits of EVs are significantly reduced. Could green hydrogen fill these gaps?

When used as a fuel, green hydrogen produces zero carbon emissions. This makes it an ideal energy solution for a world striving to reduce greenhouse gas emissions and combat climate change.

But what really sets green hydrogen apart as an alternative fuel is its higher energy density compared to batteries. Producing EV batteries is an energy-intensive process, often involving the mining of rare earth metals. This can lead to significant environmental degradation. However, advancements in battery technology and recycling programs are being developed to mitigate these.

Hydrogen fuel cell vehicles can be refueled at the same speed as internal combustion engine (ICE) vehicles, eliminating the lengthy charging times associated with EVs, and significantly reducing vehicle downtime, especially in commercial uses like hauling.


Comparing cost-effectiveness and scalability

In terms of price, EVs currently have the upper hand, with cheaper battery prices and more developed charging infrastructure making them the more desirable option.

The capital expenditure associated with green hydrogen production systems is also significant, primarily due to the price of electrolyzers — the devices used to split water into hydrogen and oxygen using renewable energy. The operational expenditure is also substantial, driven by the high electricity costs associated with the electrolysis process.

But all these things may change. According to a report from the Hydrogen Council, the cost of producing green hydrogen could fall by 50% by 2030 as the technology matures and scales up. This reduction could make green hydrogen a more cost-effective and sustainable alternative fuel source.


Which one is better?

The answer is — it depends.

The future of transportation is not just about choosing the best technology — it's about making the right choice for the right needs.

For example, hydrogen cars have a quicker refueling time compared to the lengthy charging times of EVs. This makes them suitable for energy-limited use cases like long-haul trucks and airplanes, where electric vehicles may fall short due to their limited range and charging requirements. Electric cars seem better suited for short to medium-range applications, especially in urban settings.

In short, we can look forward to a future with multiple clean, efficient, and sustainable options for getting around. It's not a question of one replacing the other, but rather combining both and using them to their strengths.


You've likely heard a lot about electric vehicles lately, as well as news about legislation to reduce carbon emissions from vehicles. But there's another kind of zero-emission vehicle, one that emits only water vapor as it carries you down the road. That's the hydrogen fuel-cell vehicle, related to an EV but with specific differences that make hydrogen cars different and much rarer.

To date, about 2.5 million EVs have been sold in the U.S. By contrast, as of mid-2022, 15,000 or fewer hydrogen-powered vehicles can be found on U.S. roads. All of them will be in California, the sole state with a network of retail hydrogen fueling stations to make the cars usable.


Hydrogen Cars Currently Available

Since 2015, three hydrogen -powered cars have been offered for sale from three different car companies: the Honda Clarity Fuel Cell, the Hyundai Nexo SUV, and the Toyota Mirai. But Honda has now ended production of all models of the Clarity, and Hyundai has sold fewer than 1500 Nexo SUVs thus far.

Toyota, the company most devoted to hydrogen power as an alternative to battery-electric vehicles, has sold roughly 10,700 Mirai sedans across two generations in the U.S.—though in some periods it resorted to substantial discounting to move them. (Honda does not break out sales of its Clarity Fuel Cell model from the plug-in-hybrid and battery-electric Clarity versions.)


What is a Hydrogen Car?

A hydrogen fuel-cell vehicle (HFCV for short) uses the same kind of electric motor to turn the wheels that a battery-electric car does. But it's powered not by a large, heavy battery but by a fuel-cell stack in which pure hydrogen (H2) passes through a membrane to combine with oxygen (O2) from the air, producing the electricity that turns the wheels plus water vapor. What this means is that a fuel-cell vehicle is technically a series hybrid, which is why they are sometimes classified as fuel-cell hybrid electric vehicles (FCHEV).

To scientists, hydrogen isn't actually a fuel but an energy carrier. Ignore that distinction, though, because HFCV drivers refill their vehicles' carbon-fiber high-pressure tanks at "hydrogen fueling stations" very similar in concept to the old reliable gas station, with a similar five-minute refueling time.


You may hear that hydrogen is the most common element in the universe. At the atomic level, that's true—but hydrogen is never found in its pure state. It's always combined with other elements. Its strong propensity to bind with anything in sight makes it a good energy carrier. Creating pure hydrogen for vehicles requires using a great deal of energy to "crack" a compound like natural gas (CH4) into pure H2, with CO2 as a byproduct. (Most hydrogen today is derived from fossil fuels like natural gas.) Run through a fuel cell, the hydrogen immediately gives back that energy, in the form of electricity, as soon as it combines with oxygen. Out of the exhaust pipe comes only water vapor (H2O).


Behind the Wheel

In practice, the driver of an HFCV will find the experience almost identical to driving a battery-electric vehicle, though perhaps not one of the faster ones. There's no transmission, and the car includes regenerative braking to recapture wasted energy as it slows down.

The challenge for automotive engineers is that hydrogen fuel cells are happiest at a steady power output. That’s what makes them suitable for backup power use, for instance. But the power demands in the average car vary by an order of magnitude, from something like 15 kilowatts (20 horsepower) to keep a vehicle at a steady highway speed on a flat road to perhaps 10 or 20 times that amount for maximum acceleration to 60 mph or higher.

The fuel cell in the Toyota Mirai, the best-selling hydrogen car in the U.S., is rated at 90 kW (120 horsepower). But that's not enough to accelerate onto a fast-moving highway, so Toyota (as do other HFCV makers) adds in a high-voltage low-capacity battery, very similar to those used in gasoline-electric hybrid vehicles. It's there to supply supplemental power for short periods of intense acceleration, and it's recharged from either excess fuel-cell output when the car is cruising at a steady speed or via regenerative braking when the car slows. The three hydrogen cars sold in recent years all have EPA-rated ranges of 300 miles or more, though, like EVs, that range falls substantially at higher speeds.

Are Hydrogen Cars Safe?

HFCVs are widely considered as safe as any other car; since the high-pressure tanks are designed to survive even the highest-speed crashes without leaking or breaching. While hydrogen skeptics routinely cite the Hindenburg explosion of 1937, the hydrogen tanks and their hardware would likely survive even if the rest of the car were destroyed in a crash. No injuries or deaths specific to the hydrogen components have been recorded in the relatively small number of HFCVs sold to date.


Pros and Cons of Hydrogen Fuel-Cell Vehicles

HFCVs have some of the same positive features as battery-electric cars: they’re smooth, quiet, and peaceful to drive—and they emit no carbon dioxide or other harmful exhaust out their tailpipes, just water vapor. They also lack the charging time problem that EVs have; it takes just five minutes or so to refuel them for another 300- to 400-mile stint.

There are a few disadvantages, however, the most challenging being the availability of hydrogen fuel. While plans a decade ago called for California to have 100 hydrogen stations by now, in reality, the number is about 60.

Most problematic, not all those stations are online and available for fueling at all times. You can count the total number of "H70" green dots in the real-time Station Status report maintained by the California Fuel Cell Partnership to see how many are live at any given moment. Many hydrogen drivers rely on that app to map their fueling stops before they venture out.



Hydrogen Fueling Stations

Fueling a hydrogen car comes naturally over time, but aligning the heavy nozzle and sealing it properly so the car and pump can communicate electronically can require some practice. Today's stations can often only fuel two to five vehicles before they go offline for up to half an hour to repressurize.

As HFCV drivers in the San Francisco Bay Area discovered in June 2019, the infrastructure for supplying hydrogen to retail outlets is very thin. An explosion cut off supply to nine of the area’s 11 hydrogen stations, requiring diesel trucks to transport tanks of compressed hydrogen hundreds of miles from Southern California overnight.

Drivers who depended on their hydrogen vehicles to get them to work had to set alarms for the wee hours, in hopes of reaching a fueling station in time to get some of the limited hydrogen fuel. Toyota ended up refunding several months of lease payments to Mirai drivers across the state who couldn’t reliably use their cars.

The main contrast, and biggest disadvantage, of hydrogen cars compared to EVs is that they're similar to gasoline cars in that they can’t be “refueled” or recharged at home overnight. But unlike gasoline cars, for which there’s a well-developed set of more than 100,000 fuel stations nationwide, hydrogen drivers are utterly dependent on both a reliable supply of the gas itself and an available—and properly operating—high-pressure fueling station.


Cost of Hydrogen Fuel

With hydrogen fuel a specialized commodity for the general public, the small network of retail stations naturally charges high prices. To quote the California Hydrogen Business Council, “Currently, a kilogram of hydrogen costs between $10 and $17 at California hydrogen stations, which equals about $5 to $8.50 per gallon of gasoline” to cover the same distance. (A Toyota Mirai hydrogen car holds about five gallons of hydrogen.)

To offset this disadvantage, Honda, Hyundai, and Toyota have all offered their lessees and buyers free hydrogen fuel for various periods. Each manufacturer has a slightly different offer: A Toyota Mirai comes with up to $15,000 of complimentary hydrogen, while a Hyundai Nexo includes the same $15,000 over a three-year lease or up to six years of ownership.

After those offers expire, however, the driver is on their own. And if hydrogen can be compared to gasoline at $5 to $8.50 a gallon, note that charging an EV overnight usually equates to gasoline at just $1 to $2 a gallon.


Servicing a Hydrogen Car

Like electric cars, hydrogen vehicles require dealership service centers to exercise some special precautions. HFCVs have the same high-voltage battery packs as a hybrid, plug-in hybrid, or electric car, but they also have one or more armored, carbon-fiber tanks to hold pure hydrogen under extremely high pressure: 10,000 pounds per square inch (psi), or 700 bar in metric.


Normal service for a hydrogen car that doesn’t involve the hydrogen tanks, the fuel-cell stack, or the plumbing that connects them is just like any other vehicle. But if any of those components have to be handled, the state of California has a set of rules to ensure any escaping hydrogen doesn’t run the risk of an explosion.

Those include largely draining the hydrogen tanks of their fuel in specific types of outdoor areas away from buildings. Then the rest of the system is purged of all remaining hydrogen by flushing components with various gases, a process that takes between 30 and 180 minutes.


The Future of Hydrogen Cars

If you’re in California, and you’re interested in a zero-emission vehicle powered by an electric motor, a hydrogen vehicle may be worth considering. But at the moment, it’s something of a risk. Creating a brand-new fueling network from scratch has proven to be far more problematic—both expensive and unreliable—than automakers envisioned, and the fuel is pricier for drivers than gasoline.

Lacking that hydrogen fuel, delivered at 10,000 psi, an HFCV is no more than a large, pricey doorstop. If we had to guess, we’d suggest the future for passenger cars is more likely to be electric.


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