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Fuel Cell Systems

Efficient Engines Powering Clean Mobility

Fuel cells utilize a combination of hydrogen and oxygen to produce electrical energy. This chemical reaction provides external energy, similar to a battery. However, while batteries are limited by their charging capacity, energy in fuel cells is continually supplied through hydrogen and oxygen gases. 

This means electrical energy can be produced at a higher efficiency than simply burning hydrogen to produce heat to drive a generator, because it is not subject to the thermal bottleneck from the second law of thermodynamics.  

Since the only by-product of this chemical reaction is water, fuel cells are pollution-free, making them a smart solution as a cleaner, more efficient source of energy. 


With increased durability and continual R&D, fuel cell systems have a multitude of potential and realized applications, including military vehicles, transit, and more.


We power clean fleets worldwide, helping you achieve your sustainability goals.


Our team of industry-leading engineers strive to increase the power of motors and electronics for even the most stringent applications.


Eliminate range anxiety with technology that helps you go further.

Fuel Cell Products

FCe™10 (10kW)

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FCe™40 (40kW)

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FCe™50 (50kW)

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US Hybrid Fce80 Fuel Cell

FCe™80 (80kW)

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FCe™100 (100kW)

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The Science
of Hydrogen

Hydrogen Fuel Cell Technology

Combining a mole of hydrogen gas and a half-mole of oxygen gas from their normal diatomic forms produces a mole of water. A detailed analysis of the process makes use of the thermodynamic potentials. This process is presumed to be at 298K and one-atmosphere pressure, and the relevant values are taken from a table of thermodynamic properties.

Energy is provided by the combining of the atoms and from the decrease of the volume of the gases. At temperature 298K and one-atmosphere pressure, the system work is

W = PDV = (101.3 x 103 Pa)(1.5 moles)(-22.4 x 10-3 m3/mol)(298K/273K) = -3715 J

Since the enthalpy H= U+PV, the change in internal energy U is then

DU = DH – PDV = -285.83 kJ + 3.72 kJ = -282.1 kJ 

The entropy of the gases decreases by 48.7 kJ in the process of combination since the number of water molecules is less than the number of hydrogen and oxygen molecules combining. Since the total entropy will not decrease in the reaction, the excess entropy in the amount TDS must be expelled to the environment as heat at temperature T. The amount of energy per mole of hydrogen which can be provided as electrical energy is the change in the Gibbs free energy:

DG = DH – TDS = -285.83 kJ + 48.7 kJ = -237.1 kJ

For this ideal case, the fuel energy is converted to electrical energy at an efficiency of 237.1/285.8 x100% = 83%

Comparison of Electrolysis and the Fuel Cell Process

In comparing the fuel cell process to its reverse reaction, electrolysis of water, it is useful to treat the enthalpy change as the overall energy change. The Gibbs free energy is that which you must supply if you want to drive a reaction, or the amount that you can achieve the reaction is working for you. In the electrolysis/fuel cell pair where the enthalpy change is 285.8 kJ, you must put in 237 kJ of energy to drive electrolysis and the heat from the environment will contribute TDS=48.7 kJ to help you. Going the other way in the fuel cell, you can get out the 237 kJ as electric energy, but must discard TDS = 48.7 kJ to the environment.

Success Story

US Hybrid Provides SARTA with Five Hydrogen Fuel Cell Paratransit Vans

Download the case study to learn how US Hybrid designed and manufactured five hydrogen fuel cell paratransit vehicles for Stark Area Regional Transit Authority (SARTA) for transit operation.

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