Electric, hybrid, hydrogen: understanding the differences

Published by on 06.24.2018 - 5 min

With the arrival of zero-emissions vehicles, we now regularly hear talk of electric cars, hybrid engines or hydrogen-powered cars. What exactly do these terms mean and how can we differentiate them? Follow this guide.

If, for a long time, picking a motor was a simple choice between petrol and diesel, a game-changing technology must be considered from now on: the electric motor. Sometimes, when it totally replaces its precedent, the venerable combustion engine, we are dealing with an electric car. In other cases, the two different technologies live together in the same vehicle. That is the hybrid model, which breaks down further based on the different levels of interaction between the two motors, according to the charging and energy storage systems chosen by the manufacturer.  These are the different variations possible, with explanations of each.

All-electric cars: the most advanced

Renault Zoe electric car engine

The electric car is currently the most advanced and affordable solution to the environmental challenges of global warming and air pollution that is on the market. What makes it unique? The combustion engine, the fuel tank and the exhaust pipe are all gone, and in their place is a battery-powered electric motor.

The car gets charged at special stations located at home, in the parking lot of your workplace or in public places. With a potential range of several hundred kilometres, it runs silently, consumes no energy when stationary and produces no tailpipe emissions. Not to mention the pleasure of driving one. All the torque that the electric motor can provide is made available instantly, for smooth and immediate acceleration.

And finally, due to the lack of combustion and of moving mechanical parts, the electric motor is exceptionally reliable. For the driver, that means that maintenance is kept to a bare minimum.

Hybrids: the transition point

Renault Scenic yellow hybrid cardriving across city

Inside a hybrid car, you will find both a petrol (or diesel) engine and an electric unit that have been programmed to work together. How does that work? The electric motor serves as a backup to the combustion engine, decreasing the stress on the latter and, therefore, lowering fuel consumption. The small onboard battery recharges during braking or deceleration by converting the speed into energy. A hybrid car remains, nonetheless, primarily dependent on fossil fuels: the range when the car uses 100% electric power rarely exceeds a few kilometres.

Rechargeable hybrid cars, to go even further

Rechargeable hybrid cars, often given the acronym PHEV, for Plug-in Hybrid Electric Vehicles, want to address that shortcoming. How do they work? A larger capacity battery is integrated into the chassis and a socket is added, allowing for independent recharging via an electrical outlet at home or at a charging station. With those tweaks, the electric motor transforms into a true alternative to the combustion engine for most everyday travel. Still, burning petrol remains an option for long distances, like going on holiday.

Using the combustion engine to extend the range

Another option is to use an electric motor and batteries for driving, but to add a small petrol engine that is dedicated to keeping them charged: we call that a range-extended electric car. For this variant, the battery has a large capacity and is able to be charged at a station. The car is able to run on electric power for everyday use, without any tailpipe emissions. The combustion engine intervenes only as a support, operating in a manner similar to a power generators.

Hydrogen cars: the challenger

Hydrogen pomp station

Today, the majority of electric cars use batteries that are based on lithium-ion technology, but there exist other ways to store energy. Hydrogen fuel cells, for example, make it possible to generate electricity from the eponymous gas, produced by the decomposition of water or methane. Within the cell, the gas is converted into electricity through a chemical reaction with the oxygen present in the surrounding air. It is fed by a tank that contains the gas stored at a very high pressure (several hundred bars).

Some obstacles still remain. The manufacture of fuel cells, for example, requires rare metals as well as an energy source, which may or may not be renewable. Large-scale adoption would also require setting up infrastructure that is dedicated to the production and distribution of hydrogen.

Electric, hybrid: ongoing innovation

Renault Zoe electric car charging ghosted view

Electric power has made enormous strides since nickel-cadmium batteries. Modern battery packs no longer need to feel embarrassed when compared to combustion engines. Hidden inside the chassis, lithium-ion batteries are safe and, at the end of their life cycles, handled through increasingly efficient recycling processes. They are making gains in lightness, compactness and capacity, which increase the range of the cars that contain them. With the help of technological innovations, the dominance of the electric car will soon be undeniable!

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