Electric vehicles (EVs) come in three main types:
- Battery electric vehicles (BEVs) are powered solely by electricity stored in large batteries within the vehicles. The battery powers an electric motor which in turn drives the vehicle. The battery needs to be recharged by plugging into recharging points that are connected to the electricity grid.
- Plug-in hybrid electric vehicles (PHEVs) operate using the vehicle’s petrol or diesel engine or by using electricity to power an onboard electric motor. However, PHEVs have much larger batteries than conventional HEVs and so can also be charged from the mains when not in use – hence ‘plug-in’ – and this means the vehicle can cover a greater distance.
- Hybrid electric vehicles (HEVs), often simply referred to as hybrid vehicles, are powered by a combination of electricity stored in a battery and either a petrol or diesel internal combustion engine. A hybrid vehicle does not need to be plugged in to recharge its battery, as this is recharged automatically as the vehicle is being driven.
The Smart Grid will enable charging of batteries on BEVs and PHEVs to be done in the most cost effective way. Electric vehicles owners will plug in their vehicles at night when electricity is cheaper to generate. Doing so will help the grid have a better match between on-peak and off-peak times of the day.
Electric vehicles will provide a demand for renewable electrical energy at times when other grid demand would be low. Therefore the use of renewable resources can be maximised and not limited by night-time falls in demand.
This use of renewable energy will displace the consumption of fossil fuels in transport and reduce transport related carbon emissions.
Additional information on this topic can be found at
SEAI buyers guide to electric vehicles.pdf, Nov 2007
SEAI Electric Vehicle conference, Feb 2009
SEAI publications section