Various technologies can be applied to electric vehicles: fully electric, standard hybrids and rechargeable hybrids. Hybrid cars are currently those most commonly found on the roads, even though the fully electric vehicle is very much in the public eye. The rechargeable hybrid is a compromise that could win over a great many drivers.

See also: 'How much power does an electric car use?'

Fully electric vehicles

As its name indicates, a fully electric car runs on electricity alone. Its greatest asset is that it produces zero emissions.

However, the battery has to be recharged for several hours and its range is limited. Most models can only cover 100 to 150 km after being charged.  So electric cars are suitable for use in towns and cities or for short journeys, but are unable to meet everyone’s needs at the moment.

The standard hybrid

The hybrid car has been around for over 20 years now. It has two engines, one electric and one heat (petrol or diesel), which it uses as required. Depending on the level of hybridisation of these two engines, these vehicles are referred to as:

• micro-hybrids
• mild hybrids
• full hybrids.

In a full hybrid (the most common model), the electric engine is used to start up the vehicle and when travelling at low speeds. So the car can run in electric mode for one or two kilometres. After this, the petrol engine takes over. The electric engine recharges only when the vehicle is running, in particular by recovering the energy released when the driver breaks.

The disadvantages?

• two engines means twice the weight and twice the manufacturing energy costs!
• In fact, it only lives up to its potential in urban settings, as it becomes a petrol or diesel vehicle again on the motorway.
• So the emissions savings vary between 10 % and 50 %, depending on how the vehicle is used. 

The rechargeable hybrid or “plug-in”

The rechargeable hybrid car works like a standard hybrid, except that it can be recharged directly and quickly (two hours) using an ordinary electric socket. This increases its range in electric mode, so that it can cover between 20 and 60 km. Enough to drive in a town or city without producing emissions!

Compared with the standard hybrid, the rechargeable hybrid increases your comfort, above all. In terms of emissions, it does a little better, provided that you drive it properly and use the electric engine as much as possible.

Another concept: the range extender

Electric vehicles with a range extender have also appeared on the market. They have a small petrol engine, not to drive the vehicle forward, but to recharge the battery that supplies the energy.

(See also: 'Are natural gas cars a real alternative?')