Welcome to the 37th edition of our automotive engine series. In the previous article, we analyzed Variable Compression Ratio Engines, reviewing their ability to optimize performance and efficiency by dynamically adjusting compression ratios based on driving conditions.

In this article, we will take a closer look at Hydrogen Fuel Cell Technology, examining its potential to solve the pressing challenge of vehicle emissions while maintaining the convenience and performance that drivers expect. We will analyze how this technology converts hydrogen into electrical energy, powering vehicles with zero harmful emissions while offering rapid refueling capabilities that overcome the limitations of traditional battery-electric vehicles.

By the end of this article, you will have a detailed understanding of the key aspects of hydrogen fuel cell technology, including how it works, its benefits and challenges, and its potential to impact industries beyond transportation. We will also provide actionable insights for buyers considering hydrogen-powered vehicles, investors looking to capitalize on this emerging market, and professionals with appetite for career opportunities in this growing field.

Hydrogen fuel cells are a key technology in the transition to clean energy. They convert the chemical energy of hydrogen into electricity through an electrochemical reaction, emitting only water vapor as a byproduct. As demand for sustainable energy solutions rises, hydrogen fuel cells are gaining prominence, particularly in transportation and power generation.

The evolution of automotive technology has significantly impacted mobility, moving from internal combustion engines to electric vehicles (EVs). Now, hydrogen fuel cells are offering a promising alternative for zero-emission transportation, with fuel cell vehicles (FCVs) providing advantages such as faster refueling and longer driving ranges compared to traditional gas-powered and battery electric vehicles.

Climate change, driven by fossil fuel emissions, and air pollution from transportation and industry are major global challenges. These issues contribute to rising temperatures, extreme weather, and health problems. A shift away from fossil fuels is essential, with renewable energy sources like solar and wind being key, though they are often intermittent and require storage solutions.

Hydrogen fuel cells offer a clean, efficient alternative. They generate electricity by combining hydrogen with oxygen, producing only water vapor. In transportation, they provide a low-emission option with fast refueling and long range. In industry, they can power high-temperature processes and serve as energy storage to balance renewable power supply. As demand for sustainable energy grows, hydrogen fuel cells are positioned to play a crucial role in reducing emissions and reliance on fossil fuels across various sectors.

A hydrogen fuel cell is a device that converts chemical energy into electrical energy through an electrochemical reaction. The process involves hydrogen gas (H₂) reacting with oxygen (O₂) from the air to produce electricity, heat, and water as the only byproduct. This process is highly efficient, and unlike traditional combustion engines, it generates zero emissions aside from water vapor. Essentially, a hydrogen fuel cell mimics the process of photosynthesis—capturing the energy stored in hydrogen molecules and releasing it as clean electricity.

Hydrogen fuel cells generate electricity through a process called an electrochemical reaction. This reaction occurs when hydrogen gas is combined with oxygen from the air, releasing energy in the form of electricity. Here’s a simple, step-by-step explanation of how this works:

Hydrogen gas (H₂) is stored in a high-pressure tank and fed into the anode (the negative side of the fuel cell). The hydrogen gas molecules are composed of two hydrogen atoms (H₂).

Once hydrogen enters the anode, it passes through a special catalyst. This catalyst helps split each hydrogen molecule into two protons (positively charged hydrogen ions) and electrons (negatively charged particles).

The electrons travel through an external circuit from the anode to the cathode (the positive side of the fuel cell). This movement of electrons creates an electric current, which is the electricity that powers devices such as electric vehicles or homes.

At the same time, the protons (hydrogen ions) move through the electrolyte, a special membrane that separates the anode from the cathode. The electrolyte allows only the protons to pass through, blocking the electrons and ensuring they travel through the external circuit to generate electricity.

Oxygen (O₂) from the air is drawn into the fuel cell through the cathode. The oxygen molecules are then combined with the protons (that have passed through the electrolyte) and the electrons (that have traveled through the external circuit).

At the cathode, the protons, electrons, and oxygen combine to form water (H₂O), which is expelled from the fuel cell as harmless water vapor. This is the only byproduct of the reaction.

To better understand how these steps come together, let’s look at the key components that make up a hydrogen fuel cell system:

This is the negative side of the fuel cell, where hydrogen is introduced and split into protons and electrons. The anode is equipped with a catalyst (usually platinum) that helps break the hydrogen molecules into their parts.

2. Cathode
This is the positive side of the fuel cell, where oxygen from the air enters and combines with the protons and electrons to form water. The cathode also contains a catalyst to facilitate the oxygen reaction.

3. Electrolyte
The electrolyte is a special membrane that allows only the protons (hydrogen ions) to pass through, while blocking electrons. This ensures the electrons must travel through an external circuit, generating electricity in the process.

4. External Circuit
This is the path through which the electrons travel from the anode to the cathode. As the electrons move through this circuit, they generate electrical power, which can be used to run motors in vehicles or provide electricity for other devices.

Hydrogen fuel cells come in several different types, each with its own unique features, benefits, and best-use scenarios. These types primarily differ in the materials they use for their electrolyte and their operating conditions. Let’s take a look at an overview of the most common types of hydrogen fuel cells and how they differ:

Also known as Polymer Electrolyte Membrane Fuel Cells (PEMFC), these are the most commonly used type of fuel cell for transportation and portable power applications. The electrolyte in PEMFCs is a solid polymer membrane that conducts protons, allowing the electrochemical reaction to take place.

PEMFCs are primarily used in vehicles (like hydrogen cars, buses, and trucks), portable devices, and backup power systems.

These fuel cells operate at lower temperatures (around 60-100°C), making them suitable for quick start-up times and efficient use in transportation and mobile applications.

PEMFCs are highly scalable for various applications, from small devices to large vehicles, making them a central focus for the automotive industry.

Alkaline fuel cells use an alkaline electrolyte, typically potassium hydroxide (KOH) dissolved in water, which facilitates the electrochemical reaction. They were one of the earliest types of fuel cells developed and have been used in some space programs.

AFCs are most commonly used in stationary applications, including power generation and some specialized transportation uses. They are also used in research and space missions, as they are highly efficient in environments with pure hydrogen and oxygen.

AFCs have higher efficiency than PEMFCs in some contexts, but they require high-purity hydrogen and are more sensitive to impurities, limiting their broader commercial use.

AFCs are less versatile than PEMFCs, as they are highly sensitive to contamination, making them less suitable for automotive or large-scale applications. However, they are still valuable in specific industries like space exploration and research.

PAFCs use liquid phosphoric acid as the electrolyte. These fuel cells operate at a higher temperature than PEMFCs, typically between 150-200°C, allowing for better tolerance to impurities in hydrogen.

PAFCs are commonly used in stationary applications, such as power plants and backup power systems for buildings, hospitals, and critical infrastructure.

PAFCs offer moderate efficiency and can be used for combined heat and power (CHP) applications, where both electricity and heat are valuable.

While PAFCs are not typically used in transportation, their ability to produce both power and heat makes them ideal for stationary, commercial, and industrial applications. They are more established in larger-scale energy systems than other fuel cell types.

Solid Oxide Fuel Cells use a ceramic electrolyte that conducts oxygen ions at high temperatures, usually between 500-1,000°C. This allows SOFCs to run on a variety of fuels, not just hydrogen, including natural gas and biogas.

SOFCs are used in large-scale stationary applications like power generation, both for grid-based and off-grid energy production. They are also being researched for industrial applications requiring high-temperature operations.

SOFCs have high electrical efficiency and can achieve even higher efficiency when used in combined heat and power (CHP) systems. However, their high operating temperatures make them unsuitable for mobile applications like vehicles.

Due to their ability to use different fuels and their high efficiency, SOFCs show great potential for use in large-scale power plants and industrial applications, but are less practical for transportation.

Molten Carbonate Fuel Cells use a molten carbonate salt mixture as the electrolyte, operating at temperatures between 600-700°C. This allows MCFCs to be highly efficient and also capable of using a variety of fuels, including natural gas, hydrogen, and biogas.

MCFCs are primarily used in large-scale stationary applications, such as power plants and industrial processes, where high-temperature operations and fuel flexibility are needed.

Like SOFCs, MCFCs can achieve very high efficiencies and can also be used in CHP systems. However, their high temperatures and sensitivity to fuel quality limit their use in more mobile applications.

MCFCs are suitable for industrial-scale power generation and can be part of larger energy systems, but their high operating temperatures make them impractical for consumer applications.

Hydrogen fuel cells offer several key benefits, making them a strong alternative to fossil fuels and electric vehicles (EVs) in the transition to cleaner energy:

Hydrogen fuel cells produce only water vapor as a byproduct, eliminating harmful pollutants and greenhouse gases. This makes them ideal for improving air quality and reducing carbon footprints, especially in urban areas.

2. High Energy Efficiency

Fuel cells are more efficient than traditional combustion engines and many EVs, as they convert energy directly into electricity with minimal loss.

3. Quick Refueling

Hydrogen vehicles can be refueled in 3-5 minutes, significantly faster than the lengthy charging times required for EVs. This makes hydrogen fuel cells more practical for long-distance travel and high-utilization sectors like public transport.

4. Versatility in Applications

Hydrogen fuel cells can power a wide range of applications, including passenger vehicles, buses, trucks, trains, industrial processes, and even stationary power generation. They can provide clean, decentralized power for homes, businesses, and critical infrastructure, offering reliable energy in remote areas or off-grid locations.

While hydrogen fuel cells hold promise, several challenges must be addressed to fully realize their potential:

The high cost of hydrogen fuel cells, due to expensive materials like platinum catalysts, and the lack of large-scale manufacturing drive up production costs. Additionally, hydrogen refueling stations are limited, and the infrastructure to support them requires substantial investment and coordination. Most stations are concentrated in specific regions, making long-distance travel with hydrogen vehicles impractical in many areas.

2. Hydrogen Production

Currently, most hydrogen is produced through steam methane reforming (SMR), which relies on natural gas and releases significant CO2, diminishing its environmental benefits. While green hydrogen, produced using renewable energy through electrolysis, is the ideal solution, it remains costly and is not yet scalable. Widespread adoption will depend on technological advancements and significant investments to reduce costs.

3. Storage and Transportation

Hydrogen has low energy density by volume, requiring high-pressure or cryogenic tanks for storage. Both methods pose engineering challenges and safety concerns due to hydrogen's flammability. The complexity and cost of building infrastructure for storing and transporting hydrogen fuel further hinder its widespread adoption.

Hydrogen fuel cells have a wide range of potential applications across multiple industries, offering clean, efficient energy with minimal environmental impact. Here’s how hydrogen fuel cells are being used today and their potential for significant future impact:

Hydrogen fuel cells are increasingly used in transportation, providing long-range, zero-emission alternatives to gasoline and diesel vehicles.

Automakers like Toyota and Hyundai offer hydrogen-powered cars, for example, Toyota Mirai and Hyundai Nexo, with ranges of 300-400 miles and refueling times of just a few minutes.

Public Transit

Hydrogen buses, already operating in cities like London and California, provide eco-friendly public transportation with long range and fast refueling.

Trucks and Freight
Hydrogen fuel cells are also being used in long-distance commercial trucks, for example Nikola Motors, reducing downtime compared to battery electric vehicles.

Hydrogen trains like the Coradia iLint provide an environmentally friendly solution for rail transport, especially in areas without electrified rail networks.

Hydrogen fuel cells can supply backup power or serve as a primary energy source, storing excess renewable energy and releasing it during peak demand periods.

Industries requiring large energy amounts are using hydrogen fuel cells for high-efficiency, continuous power, especially in off-grid locations.

Hydrogen fuel cells provide both electricity and heat, improving efficiency for industrial facilities, hospitals, and residential buildings.

2. Portable Power

Hydrogen fuel cells are also gaining traction in portable power applications, offering efficient, reliable solutions for backup power in remote areas and for consumer electronics.

Hydrogen fuel cells can provide backup power during outages, offering clean energy without relying on diesel generators.

Small hydrogen fuel cells are being developed to extend the battery life of portable devices like laptops and smartphones, providing long-lasting power with minimal environmental impact.

Several companies are making significant strides in hydrogen technology, leading the charge in various applications of hydrogen fuel cells:

Toyota has been a pioneer in hydrogen fuel cell vehicles with its Toyota Mirai sedan, one of the first commercially available hydrogen-powered cars. The company is also investing heavily in hydrogen infrastructure and fuel cell technology for both passenger and commercial vehicles.

Hyundai’s Nexo is a hydrogen-powered SUV that offers a long driving range and fast refueling times, making it a strong competitor in the clean transportation market. Hyundai is also exploring hydrogen fuel cells for buses and trucks, particularly in regions looking to decarbonize public transportation.

Focused on developing hydrogen-powered trucks, Nikola is positioning itself to revolutionize long-haul freight transport with its zero-emission vehicles. The company is working on establishing a network of hydrogen refueling stations to support the growing demand for hydrogen trucks.

As a leading player in the energy sector, Siemens is working on integrating hydrogen fuel cells into industrial power systems. Their projects aim to use hydrogen as a flexible and clean energy source for power generation, both for the grid and for industrial use.

Plug Power

A leader in hydrogen fuel cell technology, Plug Power is focused on providing hydrogen-powered solutions for a variety of sectors, including material handling, stationary power, and transportation. The company is working on advancing hydrogen infrastructure and scaling up green hydrogen production.

Hydrogen fuel cell technology plays a key role in the transition to cleaner, sustainable energy. With applications in transportation, power generation, and industry, hydrogen offers a low-emission alternative, producing only water vapor as a byproduct.

Hydrogen fuel cells provide benefits like fast refueling, long ranges, and low environmental impact, making them suitable for vehicles, trains, and stationary power generation.

Buyers can consider hydrogen vehicles as infrastructure develops and government incentives increase. Investors can explore opportunities in hydrogen production and fuel cell tech. Professionals may find growing career prospects in this expanding field.

Though challenges remain, hydrogen’s potential in the clean energy transition continues to grow. Stay tuned for our next article, where we’ll analyze solid-state batteries for EVs—marking the final installment in our automotive engine series. For those who haven’t yet read our previous articles, we encourage you to revisit them for a comprehensive understanding of key automotive engine innovations.

Ciao!