The electric vehicle is ideal for use in cities as it emits no fumes and can be integrated into city-wide traffic systems where travelling distances are short. The electricity needed to charge the battery can be generated from renewable sources, which leads to a
considerable reduction in carbon dioxide emissions. However, for long journeys battery technology and electricity storage is the key point. New battery systems such as Li-ion, nickel hydride and high temperature are under development (Van Mierlo et al., 2006). Recently Mercedes has introduced a battery-powered Smart car. It is powered by a high temperature (260-330°C) sodium-nickel-chloride battery with an output of 15.5kWh. The battery can be recharged from the domestic supply and takes about 8 h and gives the car a range of 50 miles. Considering the developments in battery technology driven by the mobile phone and computer industries it is likely that the range will be extended.

Hybrid vehicles

For long-range travel, hybrid vehicles appear to offer the best option. The hybrid is a combination of a battery-powered electric engine plus an internal combustion engine or fuel cell. The internal combustion engine can be used to charge the battery when in use. There are a number of options for hybrid drive trains and a number of cars available from a range of manufacturers which combine electric motors with a small petrol engine, notably the Toyota Prius.