Could hydrogen decarbonise transport?

Hydrogen as an energy carrier has major advantages over fossil fuels for mobility applications, particularly in the development of fuel cell electric vehicles (FCEVs). Here Simone Bruckner, managing director of automotive resistor manufacturer Cressall Resistors, investigates the use of hydrogen fuel and the role resistors play in unleashing hydrogen's potential.

Despite the growing maturity of the sector, hydrogen technologies still need considerable development in order to reach net zero targets and to become a viable fuel source for automotive applications. Making usable, renewable hydrogen is no easy feat — so where’s the best starting point?

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Clean is green ??

Hydrogen can be produced in many ways. Currently, most hydrogen is generated by mixing natural gas and steam to create hydrogen and carbon dioxide, in a process known as steam methane reformation.

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Ideally, we need to make green hydrogen, which uses renewable electricity to separate the hydrogen and oxygen atoms that make up water in a process called electrolysis. This results in a fuel with zero carbon emissions.

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FCEVs turn this hydrogen into electricity by combining the fuel with air and pumping it into the fuel cell. Once inside the fuel cell, a chemical reaction is triggered, resulting in the extraction of electrons from the hydrogen. These electrons then create electricity, which is stored in a small battery used to power the vehicle.

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Recharging with regenerative braking ??

To improve the efficiency of the vehicle, excess kinetic energy can be retained to recharge an EV’s battery using a process called regenerative braking.

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This is possible because the motor in an EV runs in two directions. Electrical energy moving the motor forwards drives the car, but reversing the direction of the motor puts this excess energy back into the battery.

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Ensuring electrical safety ?

The principle of regenerative braking is simple, but in practice further technologies are required to ensure the vehicle operates safely. If the battery is already fully charged, regenerative braking isn’t viable. But this excess energy has to go somewhere to make sure the EV stops when the driver brakes.

Here, a dynamic braking resistor (DBR) is used. These can safely dissipate the excess energy and ensure the system remains operational, while maximising the efficiency of the fuel and the vehicle.

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While a relatively small component in FCEV production, dynamic braking resistors play an integral part in making FCEVs safer and more efficient, as well as helping to pave the way for more sustainable transport.

Cressall offers a range of DBRs to suit vehicles of all shapes and sizes. You can find out more about our DBRs on our website or get in touch with a member of the Cressall team here.?