Fuel cell electric vehicles (FCEVs) are powered by hydrogen. They are more efficient than conventional internal combustion engine vehicles and produce no tailpipe emissions—they only emit water vapour and warm air. FCEVs and the hydrogen infrastructure to fuel them are in the early stages of implementation.

Like all-electric vehicles, fuel cell electric vehicles 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 smoothing 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.

How does hydrogen fuel cells work?

Fuel cell cars are powered by compressed hydrogen gas that feeds into an onboard fuel cell “stack” that doesn’t burn the gas, but instead transforms the fuel’s chemical energy into electrical energy. This electricity then powers the car’s electric motors. Tailpipe emissions are zero, and the only waste produced is pure water.

The construction of the fuel cell is similar to a battery. Hydrogen enters the anode, where it comes in contact with a catalyst that promotes the separation of hydrogen atoms into an electron and proton. The electrons are gathered by the conductive current collector, which is connected to the car’s high-voltage circuitry, feeding the onboard battery and/or the motors that turn the wheels.

• Fuel Cell Stack – An aggregate of numerous fuel cells that combine oxygen and hydrogen to generate electricity and power the electric motor.

• Fuel Tank – Hydrogen gas is stored in carbon-fibre reinforced tanks to provide fuel to the fuel-cell stack.

• Electric Motor – Powers the car using energy produced in the fuel cell stack.

• Battery – Captures energy from regenerative braking and provides additional power to the electric motor.

• Exhaust – The byproduct of the reaction occurring in the fuel cell stack is water vapour, which is emitted through the exhaust.

Why does Elon Musk not like hydrogen?

Tesla CEO Elon Musk has previously described hydrogen fuel cells as “extremely silly,” but his views aren’t shared by everyone in the autos sector.  Musk has been making these and similar statements for several years as the billionaire head of the electric car company has failed to see real potential in hydrogen fuel cells, despite the progress that has been made.

During an interview at the Financial Times Future of the Car summit on Tuesday, Musk was asked if he thought hydrogen had a role to play in accelerating the transition away from fossil fuels.

“No,” he replied. “I really can’t emphasize this enough — the number of times I’ve been asked about hydrogen, it might be … it’s well over 100 times, maybe 200 times,” he said. “It’s important to understand that if you want a means of energy storage, hydrogen is a bad choice.”

Expanding on his argument, Musk went on to state that “gigantic tanks” would be required to hold hydrogen in liquid form. If it were to be stored in gaseous form, “even bigger” tanks would be needed, he said.

Described by the International Energy Agency as a “versatile energy carrier,” hydrogen has a diverse range of applications and can be deployed in sectors such as industry and transport.

What are different types of fuel cells?

Despite working similarly, there exist many varieties of fuel cells. Some of these types of fuel cells are discussed in this subsection.

The Polymer Electrolyte Membrane (PEM) Fuel Cell

• These cells are also known as proton exchange membrane fuel cells (or PEMFCs).
• The temperature range that these cells operate in is between 50^oC to 100^oC
• The electrolyte used in PEMFCs is a polymer which can conduct protons.
• A typical PEM fuel cell consists of bipolar plates, a catalyst, electrodes, and the polymer membrane.
• Despite having eco-friendly applications in transportation, PEMFCs can also be used for the stationary and portable generation of power.

Phosphoric Acid Fuel Cell

• These fuel cells involve the use of phosphoric acid as an electrolyte to channel the H⁺
• The working temperatures of these cells lie in the range of 150^oC – 200^oC
• Electrons are forced to travel to the cathode via an external circuit because of the non-conductive nature of phosphoric acid.
• Due to the acidic nature of the electrolyte, the components of these cells tend to corrode or oxidize over time.

Solid Acid Fuel Cell

• A solid acid material is used as the electrolyte in these fuel cells.
• The molecular structures of these solid acids are ordered at low temperatures.
• At higher temperatures, a phase transition can occur which leads to a huge increase in conductivity.
• Examples of solid acids include CsHSO₄ and CsH₂PO₄ (caesium hydrogen sulfate and caesium dihydrogen phosphate respectively)

Alkaline Fuel Cell

• This was the fuel cell which was used as the primary source of electricity in the Apollo space program.
• In these cells, an aqueous alkaline solution is used to saturate a porous matrix, which is in turn used to separate the electrodes.
• The operating temperatures of these cells are quite low (approximately 90^oC).
• These cells are highly efficient. They also produce heat and water along with electricity.

Solid Oxide Fuel Cell

• These cells involve the use of a solid oxide or a ceramic electrolyte (such as yttria-stabilized zirconia).
• These fuel cells are highly efficient and have a relatively low cost (theoretical efficiency can even approach 85%).
• The operating temperatures of these cells are very high (lower limit of 600^oC, standard operating temperatures lie between 800 and 1000^oC).
• Solid oxide fuel cells are limited to stationary applications due to their high operating temperatures.

Molten Carbonate Fuel Cell

• The electrolyte used in these cells is lithium potassium carbonate salt. This salt becomes liquid at high temperatures, enabling the movement of carbonate ions.
• Similar to SOFCs, these fuel cells also have a relatively high operating temperature of 650^oC
• The anode and the cathode of this cell are vulnerable to corrosion due to the high operating temperature and the presence of the carbonate electrolyte.
• These cells can be powered by carbon-based fuels such as natural gas and biogas.

How much does a fuel cell cost?

The cost of fuel cell vehicles has been falling dramatically for years. And it will continue to drop within the next decade and beyond. 

The price of fuel cell vehicles—especially buses— has been reduced by 65% over the past 10 years. Since 2010, the cost of electrolysis-produced hydrogen has fallen by 60%, from between USD 10-$15/kg of hydrogen to as low as USD $4-$6/kg today. Recent industry reports show that they will continue to fall; offshore wind-based electrolysis shows another 60% cost reduction from now until 2030.

What are some car fuel cell startups?

Here are a few startups who are at the very top of revolutionising our future.

Standard Hydrogen Corp. – Fueling Stations

Hydrogen fuel cell-based vehicles offer a cleaner, pollution-free, and environmentally friendly riding experience compared to fossil fuel cars. US-based Standard Hydrogen Corp. aims even further. The company creates a sustainable hydrogen infrastructure, where hydrogen is produced on-site, using clean energy resources.

Hydrogen in Motion – Storage

Next to hydrogen generation and delivery, Canadian startup Hydrogen in Motion offers a hydrogen storage solution for emission-free (zero-emission) electric vehicles. Since their patented nanomaterial technology is conformable to various shapes, the storage containers can meet multiple application requirements.

Mebius – Fuel Cell

One of the different types of fuel cells is the Proton Exchange Membrane (PEM) fuel cell. It’s used mainly for transport applications. Mebius, a Slovenian company, develops components and modules for those cells, more specifically gas-diffusion electrodes, PEMs, and membrane-electrode assemblies. Their Proton Exchange Membranes as a core of hydrogen fuel cells lead to better energy density and cost-efficiency compared to commonly used production methods.

Hydra – Hydrogen-as-a-Service (HaaS)

As truck fleets are one of the main contributors to greenhouse gas emissions, they are often targeted by companies seeking a sustainable and carbon-free transport option. Canada-based Hydra offers a “dual-fuel” solution for commercial truck fleets. A plug-and-play Hydrogen Injection System (HIS) modifies the traditional diesel engine. Thus, vehicles run both on diesel and hydrogen as a shift to clean-fuel flexibility.

CleverShuttle – Carpooling

The fact that the car-sharing economy is shaping the automotive industry points to a tendency that easy access is becoming more attractive than owning a car. CleverShuttle, a Berlin-based startup, reduces traffic via carpooling and also uses electric and hydrogen fuel vehicles to create an eco-friendly, low-emission transportation system.

Conclusion

Fuel cells as a concept and the use of hydrogen as an energy carrier are nothing new, but the development of hydrogen fuel cell technology that is viable for use in commercial transport systems and infrastructures is now accelerating.

However, we are still some years away before it becomes commercially available. Fuel cells for commercial vehicles and machines have the potential to become essential for the future of transportation and infrastructure, where we strive to accelerate the development, production, and commercialization of hydrogen fuel cell solutions.

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