How to extend the access to mobility and energy to a greater part of our population while minimizing greenhouse gas emissions? This equation seems hard to solve without an alternative solution that is green hydrogen, (i.e., hydrogen produced with a hundred-percent decarbonized process).
This article deals with a central element for the use of green hydrogen : the fuel cell.
What is it ?
First, what is a fuel cell?
A fuel cell is an electrochemical power generation device that combines hydrogen fuel, with oxygen from the air to produce electricity, by means of redox reaction ; with water and heat as the only by-products.
The fuel cell generates electricity in the same way as a conventional cell and has the advantage of being self-sufficient. Indeed, unlike conventional battery which must first charge, then store and finally release electrical energy; the fuel cell continuously produces electricity. Thus, as long as it is powered by an external fuel source (hydrogen in this case), it generates electrical energy.
How does a fuel cell work ?
All fuel cells have a similar configuration, an electrolyte and two electrodes (see below), but there are different types of fuel cells based mainly on what electrolyte they use. There are six main types of fuel cells :
- PEM (proton exchange membrane)
- DMFC (direct methanol fuel cell)
- MCFC (molton carbonate fuel cell)
- PAFC (phosphoric acid fuel cell)
- SOFC (solid oxide fuel cell)
- AFC (alkaline fuel cell)
The dominant technology is the proton exchange membrane fuel cell due to its versatility, durability, and use for a range of applications.
A single fuel cell consists of an electrolyte sandwiched between two electrodes. Oxygen frome air passes over one electrode and hydrogen over the other, generating electricity, water and heat. Bipolar plates on either side of the cell help distribute gases and collect the electrical current.
At the anode, hydrogen is separated into ions and electrons using platinum (or similar catalyst), creating an electric current.
This is oxidation part : 2 H2 → 4 H+ + 4 e–
The electrons travel through an external circuit, generating the required amount of power, while the ions pass through the electrolyte to the cathode where, with the help of another catalyst, they join with the oxygen atoms to produce water.
This is the reduction part : O2 + 4 H+ 4 e– → 2 H2O
The advantages of a fuel cell
The main advantages of fuel cells are following :
- High efficiency
- Quick refuelling
- Quiet operation (Low vibration)
- Compact size
- Rapid response to changes in electrical demand
- Low maintenance costs
- Flexibility in installation and operation
- Longer ranges, increasingly important for larger, heavier vehicles.
Most fuel cells are block-formed, that is, a superposition of several single fuel cells. This specific configuration gives it great modularity in the amount of energy required in its use. Whether it is to power a drone, a train, a heavy vehicle or a building, the fuel cell finds a suitable format.
We will see later how this generated electricity can, for example, power an electric motor to drive the wheels of a vehicle.
Fields of application
Today, the Canadian Hydrogen and Fuel Cell Association (CHFCA) identifies several application areas for hydrogen fuel cells :
- Passenger cars
- Buses (urban transit and school buses)
- Trucks (urban delivery, refuse, drayage trucks near ports, distribution trucks, freight haulers)
- Airport ground support equipment, drones, planes, trains, boats (ships, ferries and pleasure craft)
- Primary power and heat for homes and buildings
- Emergency power for critical lighting, generator or other uses when regular systems fail
- Uninterrupted power supply (UPS) to provide instant protection from power outages
- Consumer electronics
- Remote construction site equipment
- Electric current generators
Let’s have a deeper look into the use of hydrogen fuel in the field of forklifts and trucking.
Fuel cells or heavy-duty transport
The heavy or intensive transport configuration grants excellent adaptability to the use of hydrogen fuel cell. Indeed, this one offers a very good autonomy, a reasonable weight and volume on board, for performances similar to the diesel engine transport.
The fuel cell provides sufficient power to a truck’s high-voltage electrical system. This is connected to both an electric propulsion motor and a backup battery.
If the fuel cell produces more electricity than is needed for the engine, the battery recharges. The backup battery serves a dual purpose, adding power and taking over when the tank runs out of hydrogen.
Also, long-range fuel cell trucks offer significant advantages over pure battery electric trucks, as weight is the enemy of mileage in this application. Gaining autonomy without reducing the payload a truck can carry is a challenge that the fuel cell can meet. And the ability to refuel quickly is of great importance to truck fleets that cannot accommodate downtime with their freight patterns.
|Fuel cell||Batteries||Thermal engine|
|Power generation||Green hydrogen||Electrical grid||Fossil fuel|
|Embedded system : weight/volume||Favorable||Unfavorable||Favorable|
|GHG emissions (CO2, NOx, etc.)||Negligible||Negligible||Important|
|Fine particle emissions||Low||Low||Important|
|Overall environmental balance (manufacturing, use, recycling, etc.)||Favorable||Favorable||Poor|
Transport lourds et intensif: Pile à combustible vs Batteries & Moteur thermique
Fuel Cells for Forklifts
Fuel cell forklifts are revolutionizing the warehouse industry. This technology competes with battery, lithium-ion, diesel and propane powered trucks. The benefits of converting to fuel cell forklifts are substantial :
A healthy environment
- No release of CO2 into the air
- No use of toxic substances such as leaking batteries
- No need for indoor ventilation
- Reduced risk of accidents or worker downtime
- High and constant performance. Unlike batteries that lose power when they go below 50% of their capacity
- High and constant performance regardless of storage conditions (outdoors, with high or low temperatures, etc.)
- H2 refill time is only a few minutes compared to several hours of recharging for batteries
- Decrease in the frequency and length of downtime related to power unit changes and recharging/filling
Lower operational costs
- The longevity of fuel cells decreases the replacement rate of forklift truck power units
- Lower maintenance costs
- Operational costs correlated with reduced refill/refill downtime
Additional commercial space
- In the absence of large battery charging stations, the saved space can be used for storage
Hydrolux, power for fuel cells in Québec
At Hydrolux, we wear several caps:
- Producer-distributor of green hydrogen
- Partner in fuel cell technologies,
- Advisor for the implementation and use of green hydrogen fuel cells.
In each case we can provide our expertise in the adoption of these new technologies and meet the needs of the transportation industry.
- Government of Canada. Canadian hydrogen and fuel cells industry. FAQ
- Office of Energy Efficiency & Renewable Energy