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What you will learn:
• Some believe Hydrogen technology is still in our future
• Thousands of OEM dollars are lost for each FCEV built
• Techs need to know that most of an FCEV’s components and systems parallel those of an electric vehicle
I’ll let you off the hook early on this one. Unless you work at one of the few OEM dealerships that support hydrogen fuel cell vehicles, you probably won’t need much technical knowledge on hydrogen (as a vehicle fuel) for a while. But knowledge is power and perhaps we will be seeing more of this technology in the future.
The implementation of fuel cell electric vehicle technology (known in shorthand as FCEVs) is progressing much slower than projected 10 years ago and is seemingly being pushed aside by the aggressive growth of electric cars. Nevertheless, many industry analysts still say that hydrogen fuel cell vehicles are our future, will be a preferred long-term choice over electric cars, and that we should be prepared to support the technology once it becomes more mainstream. I’d have to agree with them. On the surface, fuel cell vehicles look pretty darn attractive:
- They run solely on the most widely available element on the earth, hydrogen
- They are a true “zero-emission” vehicle, with only water vapor emitting from the tailpipe
- Millions of dollars in private and public money are being invested in their development
- There are multiple state and federal incentives available to buyers that can take a big chunk out of a new FCEV purchase price
So, it looks like these vehicles check all the boxes that would make them a growing force in today’s alternative and green vehicle market. So why is it then that hydrogen vehicles and their implementation just seem to be spinning their wheels? Let’s take a deep dive into fuel cell vehicles, how they work, and why they are developing at such a slow pace.
What exactly is a hydrogen vehicle?
Since the reemergence of hydrogen cars, two system configurations have been researched that utilize hydrogen as their fuel source: hydrogen-powered internal combustion engines (ICE) and hydrogen fuel cell electric vehicles (FCEVs).
A hydrogen-powered ICE vehicle is very similar to conventional cars in that it has an ICE that burns hydrogen as its fuel, similar to today’s propane and CNG vehicles. However, research into hydrogen ICE vehicles has been mostly abandoned. This is because ICE engines require a large volume of hydrogen to produce adequate torque (due to the low BTUs produced when hydrogen is burned in the engine’s cylinders). In addition, burning hydrogen in a combustion chamber goes against many of the principles behind newer technology vehicles, mainly reducing tailpipe emissions.
On the other hand, an FCEV is an advanced technology vehicle that uses a fuel cell to generate electricity. It uses hydrogen fuel to produce the electrical power that propels the vehicle. FCEVs are zero-emission vehicles, similar to electric cars. However, FCEVs produce electricity from hydrogen to drive the vehicle’s electric motor, rather than from a battery that has been charged from an EV charging station. The onboard production of an FCEV’s electricity occurs in a device that is the heart of an FCEV, a fuel cell. The fuel cell works somewhat like a battery, but the fuel cell does not run down or require charging. As long as there is a constant flow of hydrogen into the fuel cell, it will produce a steady stream of electricity and byproducts of only heat and water vapor. The heat dissipates from the fuel cell, the water vapor is removed by a tailpipe, and the electricity is used to propel the car.
FCEVs also contain a lithium battery (similar to electric vehicles) used to store excess electricity generated by the fuel cell and any power generated by the vehicle’s regenerative braking system.
So, what’s the holdup?
My first direct contact with an FCEV was in 2010, when I had an opportunity to travel to southern California on a hydrogen junket, visiting Honda and their newly released Clarity FCEV. I also toured Toyota’s hydrogen research center and was with Shell Oil Company (which at that time, was the leader in hydrogen fueling station research and implementation).
What I experienced was somewhat overwhelming. These three manufacturers were betting hydrogen vehicles were the future and were putting their money where their mouth was. The Clarity was and continues to be a fantastic vehicle; powerful, good-looking, free to fuel (at that time), and one with zero carbon footprint in its operation.
Toyota was not far behind, and although they did not have a mass-market car available to the consumer then, their research led to the Mirai, currently the world’s number one FCEV. Shell, however, was the most impressive.
We toured five different hydrogen fueling stations (each producing hydrogen differently), designed as a feasibility study for the future of hydrogen fueling. So, that was over 10 years ago. What happened?
Hydrogen cars are still costly to produce
To date, only three manufacturers offer for sale or lease FCEVs: Toyota (with their Mirai), Hyundai (and their Nexo), and the recently discontinued but still somewhat available Honda Clarity. Although rather reasonably priced (especially when you consider the technology under the hood), the word on the street is that the OEMs that produce them lose tens of thousands of dollars, for each one that goes out the door.
Hydrogen is an expensive fuel – and generally not 'green'
Right now, most of hydrogen produced for vehicle fuel is produced by the reformation of natural gas. This creates hydrogen and CO2, the primary source of climate change. Although operating an FCEV is zero-emission, the fuel production for them is not, somewhat defeating the idea that an FCEV has no climate impact.
As for the fuel, producing quality hydrogen for vehicles is expensive, with some estimates putting the price at over $16 per gallon. This price would drop once it scaled up in its production as demand grew, but the price is a current factor.
In addition, there is a push for more production of “green” or environmentally friendly hydrogen. This is accomplished by production through an electrolysis process (with electricity coming from renewable sources). However, green hydrogen costs are even greater than traditionally made hydrogen.
Hydrogen fueling stations are still few and far between – and unreliable
A quick check of the Department of Energy’s Alternative Fuels Data Center will show you that public hydrogen fueling stations exist in volume in only one state – California. For numerous reasons, California was and continues to be the center of the hydrogen vehicle universe. Jump over to the California Fuel Cell Partnership’s web page, and you’ll see that there are less than 60 fueling stations in the entire state. No fueling stations, no need to think about buying an FCEV. Even in California, the lack of fueling infrastructure becomes more critical when at any given time, 20 to 40 percent of the fueling stations there are offline for various issues.
Car availability
Without fueling stations, there is no need to sell FCEVs, is there? There are plans to add thousands of fueling stations over the next ten years, but this plan has been in place for a long time. We had a hydrogen station at West Virginia University during my time there (under a research grant from the Department of Energy), but until it was taken offline around 2013. It had fueled very few vehicles and was unreliable and problematic.
Without the capability to fuel the vehicles, few OEMs will be investing in hydrogen fuel cells beyond mid-level research and development. FCEV sales are a little stronger when looking at the global market, with just under 42,000 sold globally since 2010. However, to put that into perspective, approximately the same number of Volkswagens are sold in China in four days.
How a fuel cell works
The heart of an FCEV is the fuel cell, where the “magic” of generating electricity happens. A fuel cell relies on some simple scientific principles:
- Positively charged objects are attracted to negatively charged ones.
- Protons carry a positive (+) charge; electrons carry a negative (–) charge.
- Electricity is simply the flow of electrons.
- The catalyst of the fuel cell splits hydrogen atoms into protons and electrons, creating electricity for vehicle propulsion
What happens in a fuel cell?
Hydrogen atoms from the storage tank enter the negatively-charged side of the fuel cell — called the anode.
- The hydrogen molecules are distributed across the surface of the anode.
- As the hydrogen comes into contact with the platinum catalyst, each atom is split into a positively charged proton and a negatively charged electron.
- The protons pass through the polymer electrolyte membrane (PEM) while the electrons accumulate on the anode, creating a negative charge that pushes the electrons through an external circuit. This provides electricity for the vehicle.
- Meanwhile, on the cathode side, air containing oxygen gas (O2) enters the cathode side of the fuel cell. The two protons recombine with their electrons and then join one oxygen atom to form a water molecule — H2O.
- The water is vented to the atmosphere as more air is drawn in to continue the process.
Hydrogen safety
Although hydrogen is not a poisonous gas, it can displace oxygen in a confined area. However, it tends to diffuse rapidly. As it is lighter than air, it rises when released. Rising hydrogen gas can create a safety issue if it becomes trapped. Repair facilities and fueling stations that service hydrogen vehicles are typically designed with ample ventilation so that hydrogen gas will not collect underneath the building’s roof and can disperse in the event of a leak. Hydrogen sensors may also be installed in such facilities and be connected to an alarm system that is both audible and visual.
Hydrogen is flammable and burns with a pale blue flame that is difficult to see in daylight. The flame is smokeless and does not radiate very much heat. Therefore, it may be difficult at first to identify a hydrogen flame. An infrared camera can be used to view the heat signature of a hydrogen flame. A common straw broom can also be extended into the location of the suspected fire to see if it ignites.
As with most other gaseous-fueled vehicles, a hydrogen fuel cell vehicle will have at least one temperature relief device (TRD) mounted on the vehicle’s hydrogen storage tank. Many hydrogen fuel cell vehicles have multiple hydrogen storage tanks. If so, each tank will have at least one temperature relief device. These devices are designed to rapidly vent hydrogen gas if the temperature at the device exceeds a given temperature (approximately 230 degrees F or 110 degrees C).
What does a technician need to know?
Simply put, most of an FCEV’s components and systems parallel those of an electric vehicle. The high voltage battery, electric motor, control systems, and inverters use the same technology as EVs, and a diagnostic and repair technician familiar with electric vehicles will feel at home with the vehicle with two exceptions. The differences between EVs and FCEVs reside in the fuel storage system and the fuel cell.
As for safety, the technician should follow many of the same guidelines they follow for EVs and CNG vehicles:
Use of HV insulating gloves and over-protectors
Removal of HV battery pack service plugs before component service
Use of HV-rated meters and leads
Understanding the proper defueling methods when removing compressed hydrogen from a vehicle’s fuel tank
The hydrogen fuel storage and delivery system will be very familiar to those familiar with CNG vehicles. Hydrogen is stored in the vehicle in a fiber-wrapped fuel cylinder at pressures up to 10,000 psi, and it is filled at fueling stations similar to CNG technologies. An FCEV can be filled with hydrogen in about the same amount of time it takes to fill a gasoline or diesel vehicle (a distinct advantage over EV charging).
The fuel cell, however, will be maintained and repaired by specialized OE personnel for the foreseeable future. Fuel cells are complex, have no user or local technician parts that can be replaced, and are very well-protected pieces of technology (system operation and construction are guarded secrets). They are also the most expensive component in the vehicle and can make up over half the price of the whole vehicle. Therefore, it will be a very long time before our industry is capable of any sort of fuel cell repair at the local level.
So, when it comes to FCEVs, it could be a really good thing, especially regarding the cost of gasoline and diesel, currently. If we can get the infrastructure in place, might it be the next best technology since computerized fuel injection? I guess time will tell.
