Marc Cieslak, BBC News 4 Dec 09;
Green cars powered by alternative fuel sources have become more visible on the roads in recent years.
One cause could be the introduction of legislation and higher taxes to penalise drivers of gas-guzzling vehicles by governments around the world.
But another factor is an increase in the range of eco-friendly cars on offer. These include hybrids with a combination of petrol engines and electric motors, fully battery-powered electric vehicles and even experimental ones running on algae.
Japanese automotive giants, in particular, have been stepping up their manufacturing of environmentally-friendly cars.
Lack of infrastructure
Mitsubishi is the first to mass produce an electric car which is expected to be available for sale in Europe next year.
The firm has produced the i-Meiv which is based on an existing petrol car widely available in Japan.
The green model has seen the petrol engine replaced with an electric motor, while a lithium-ion battery is stored underneath the cabin area and also stabilises the car.
Heavy batteries can reduce the performance of a green car by weighing it down and making it slower.
The batteries can also take up to eight hours to fully charge, so these cars are a long way away from being as convenient as a quick stop at the local petrol station.
Andrew Davis, director of the UK's Environmental Transport Association (ETA), told Click that currently eco-friendly vehicles lack an infrastructure to supply them with fuel.
Although he points out that there is a practical alternative.
"Electric cars have the advantage that the infrastructure is there in the houses - people are able to drive the car onto their own drives to charge it quite easily," he said.
Free charging
Quick charging stations across Japan are attempting to speed up the fuelling time - they can charge about three quarters of the Mitsubishi i-Meiv's battery in 30 minutes for a range of around 80 miles.
Electric cars are mostly designed as city cars, but Tokyo's urban commuters have just a handful of electric charging stations.
The city is lagging behind some Western cities, such as London where there are 200 charging stations.
One Japanese chain of convenience stores is working to increase the number of charging stations with the help of local government.
Lawson stores are piloting a free charging scheme, and it runs and fuel its own fleet of electric commercial vehicles.
"In the future maybe the use of electric cars will be more widespread… that's why we are trying to introduce more charging stations," said Yuji Katayama from the store chain.
Japan is leading the way when it comes to some new technologies.
Wireless transfer
Engineers at Wasada University are collaborating with Showa Aircraft Industry on a project to replace plug-in charging stations completely.
They have adapted an electric city car to charge its batteries wirelessly through inductive charging - electromagnetic fields are used to transfer energy from the base station to the vehicle's battery.
Similar technology is found in small devices like electric toothbrushes.
The project envisages that charging plates would be placed in parking bays, or even on buses which could refuel as they allow passengers on and off.
Hydrogen fuel cells
Toyota has produced a family-sized car powered by a hydrogen fuel cell. Mixing hydrogen and oxygen creates electricity to power a hydrogen fuel cell vehicle, and its only emission is water.
The cars are refuelled at a hydrogen pump, but these are as yet very scarce.
Fuel suppliers will have to invest heavily in a hydrogen infrastructure before consumers feel the vehicles are a viable option according to Andrew Davies at ETA.
"Those sorts of technologies could be used by the bus sector and the truck sector," he said.
"It might then trickle down to the private user for the private car, but we will have to see it worked in the commercial sector first," he predicted.
Watch Click on the BBC News Channel, Saturday 5 December, 11.00 (GMT).
