Green Car Guide

What green technologies are available?

Electric Cars

An electric car uses electric motors instead of internal combustion engines. They store chemical energy in rechargeable battery packs and are more energy efficient than most conventional cars that use internal combustion engines.

They do not produce any exhaust fumes.
Some battery packs are capable of being charged from renewable energy sources, in which case would produce little pollution.
They do not produce noxious fumes.
They are much quieter than internal combustion vehicles.
Many electric cars have regenerative braking, which means that when the car brakes, the battery is partially recharged. This also reduces wear on the brakes.
Many electric cars can travel hundreds of miles without the need to recharge the battery packs.

Electric cars decrease the need for petroleum powered vehicles and reduce the effect of global warming. They have good fuel efficiency and many have an acceleration performance that exceeds that of conventional cars. However, electric cars do have some limitations:

Travel distance between battery recharging is limited. This travel time depends on the drivers performance, the shape and weight of the car and the type of battery used:

Lead-acid batteries have a range of 20 to 80 miles.
NiMH batteries can deliver up to 120 miles.
Lithium-ion batteries can deliver a range of 250 to 300 miles in a single charge.

Some cars may take a long time to recharge the battery packs.
Some cars have batteries with a short lifespan.

Although these drawbacks can be seen with electric cars, new technologies are producing batteries with a longer lifespan and reduced recharging time.

Hybrid Cars

A hybrid car uses both electric motors and internal combustion engines to run the vehicle. These cars use petrol or diesel to power internal combustion engines and use electric batteries to power electric motors. They use less petroleum than conventional cars and therefore produce less pollution.

Some hybrid cars use an internal combustion engine to generate electricity and recharge the battery, unlike electric cars that recharge the battery from an external source.
They are much quieter than conventional vehicles.
They consume less fuel compared with conventional cars, so therefore produce less air pollution.
The internal combustion engine used in hybrid cars is smaller, lighter and more efficient than conventional vehicles.
Many hybrid cars have regenerative braking, which means that when the car brakes, the battery is partially recharged. This also reduces wear on the brakes.

Hybrid cars can be more fuel efficient than conventional cars, resulting in cheaper running costs and less damage to the environment. However, there are some drawbacks to hybrid cars:

Some hybrid cars are designed to have a power boost rather than to improve fuel efficiency, in which case there would be no benefit to the environment or running cost.
Hybrid cars are generally more complex than conventional cars; this may result in increased repair costs.
Hybrid cars may be more expensive to purchase than conventional cars.

Hydrogen Cars

Hydrogen cars use hydrogen as the primary source of power opposed to petrol. They are not a huge success at the moment and only a few hydrogen cars have been produced so far. There are two ways in which hydrogen can be used to power a vehicle:

Combustion conversion, where hydrogen is burned in engines in much the same way as conventional cars.
Fuel-cell conversion, where fuel cells turn the hydrogen into electricity to power internal electric motors.

Hydrogen cars have many benefits to the environment:

These cars use oxygen from the air and hydrogen as a power source, this produces water vapour as exhaust which is better for the surrounding environment.
Hydrogen is produced at centralised power plants where the by-products of burning fossil fuels can be better controlled.
It may also be possible to produce hydrogen from renewable energy sources, this means that there would be no increase in carbon dioxide emissions.

There are many drawbacks to hydrogen cars, which is why they have not made it onto the market as of yet. It will be many years before these challenges are overcome:

They are expensive to produce.
They have high running costs and low energy efficiency.

These technical challenges are unlikely to be solved for several decades. However, Transport for London are taking the first step towards overcoming these challenges by investing in hydrogen fuel cell buses. They have a fuel cell that combines hydrogen with oxygen to produce water, this process creates electricity to power the vehicle. It is hoped that the buses will reduce noise and air pollution in London and serve as a positive influence to the rest of the world.

Solar Cars

A solar car uses solar energy to power the vehicle. It obtains solar energy by using solar panels on the surface of the car and converts it into electrical energy. There are tremendous benefits of solar cars to the environment:

There are no exhaust fumes.
There is no release of greenhouse or noxious gases, reducing global warming and improving human health.
They are quieter than conventional cars.
As they run on sunlight, there is no fuel cost.

However, solar cars are yet to make it into the market as practical transportation for many reasons:

They can only travel a limited distance without the sun, which could be problematic on cloudy days and at night.
Solar cells are very fragile and can be easily damaged.
Solar cars are built for function not comfort and can usually only fit one or two people.