Before discussing hydrogen fuel cells, let’s clarify what a fuel cell is. Fuel cells are electrochemical devices that generate electricity directly from a fuel, making them highly efficient and pollution-free.
Hydrogen fuel cells are electrochemical devices that convert hydrogen and oxygen into electricity, water, and heat through a clean chemical process. Unlike batteries that store energy, fuel cells generate electricity continuously as long as hydrogen fuel is supplied. This fuel cell produces electricity with high efficiency and low power losses.
How Hydrogen Fuel Cells Work?
The basic operation involves hydrogen gas entering the anode side of the cell, where a catalyst (typically platinum) splits hydrogen molecules into protons and electrons.
The protons pass through a special membrane called a proton exchange membrane (PEM), while electrons travel through an external circuit, creating an electric current. The membrane allows the passage of only Hydrogen ions but not electrons. At the cathode, oxygen combines with the returning protons and electrons to form water vapor, which is the only emission.
The electricity produced in the fuel cell is used to operate the electric motor that drives the vehicle, known as a hydrogen fuel cell electric vehicle, as shown in the figure below.
Types of Fuel Cells
Several types exist, each suited for different applications.
- PEM fuel cells operate at relatively low temperatures and are ideal for vehicles and portable applications.
- Solid oxide fuel cells (SOFC) work at high temperatures and are efficient for stationary power generation.
- Alkaline fuel cells were used in NASA’s space program and work well in controlled environments.
Hydrogen Fuel Cell-Applications and Advantages
- Hydrogen fuel cells power everything from cars and buses to buildings and backup power systems.
- Toyota’s Mirai and Hyundai’s NEXO demonstrate automotive applications, while companies like Bloom Energy provide fuel cell systems for industrial power.
- The only exhaust that Hydrogen fuel cell EVs produce is water vapor. These vehicles do not have a gasoline or diesel storage tank on board.
- The technology offers zero local emissions, high efficiency (often exceeding 60%), and quiet operation.
- Refueling takes minutes rather than hours, making it attractive for heavy-duty transportation.
Current Challenges
Cost remains the primary barrier, with platinum catalysts and specialized membranes being expensive. Hydrogen storage requires high-pressure tanks or cryogenic systems, adding complexity. The hydrogen supply infrastructure is limited, though growing in regions like California, Europe, and parts of Asia. Most hydrogen today comes from natural gas reforming, which produces carbon emissions, though green hydrogen from renewable electrolysis is expanding.
Future Outlook
Research focuses on reducing costs through alternative catalysts, improving durability, and scaling manufacturing. Green hydrogen production is becoming more economical as renewable energy costs decline. Major automakers, governments, and energy companies are investing heavily in hydrogen infrastructure, particularly for applications where batteries face limitations like long-haul trucking, shipping, and industrial heating.
The technology represents a promising pathway for decarbonizing sectors that are difficult to electrify directly, though widespread adoption will depend on continued cost reductions and infrastructure development.
