Greenest Cars

As concern about the state of the planet continues to grow, many motorists are looking at ways to minimise the environmental damage caused by their cars. Choosing to buy a more energy-efficient vehicle is a good place to start.

Size matters

Generally, cars with smaller engines are cheaper to run, produce less pollution and cost less on your Direct Line car insurance so they are a good bet all round for the eco-conscious motorist. But, it is also worth considering that some new cars produce less CO2 than some older, smaller CC vehicles.

But what if a small car is not for you? The Government recently launched the Act On CO2 website to inform buyers of the greenest models in each class of vehicle, from the smallest models cars up to large 4x4s. So, for example, in the small family car class, the Toyota Prius tops the green list. This hybrid model saves fuel by employing an electric motor to help the regular petrol engine when accelerating. The electric motor then recharges itself while the car is driving at a constant speed.

What if you need an executive car, or a large family car? The Government list means you can still choose the greenest model available. In the executive class, for example, the BMW 5 Series E60/E61 is the greenest, producing 136g of CO2 per km. And the greenest estate car? The Skoda Fabia estate.

Even those vilified 4x4s have different shades of green. The least-polluting large 4x4, for example, with a 2.2-litre diesel engine, is the new Hyundai Santa Fe.

In fact, diesel engines frequently perform better than petrol engines in the green stakes as they are more fuel-efficient.

Going electric

The growing band of small electric cars such as the G-Whiz may not be to everyone's taste, and they have some distinct disadvantages (such as a top speed of around just 45mph), but they are just about the greenest motors on four wheels. Not only that, they are incredibly cheap to run (from as little as 1.3p per mile). They are exempt from road tax, the London congestion charge and most parking charges in central London. And they fit into the lower priced Direct Line car insurance bands.

For those who want more oomph, the Electric Lightning GT is an electric sports car with a top speed of 130mph. It even has the option of artificially added noise for those who don't want their sports car to sound like a milk float.

Alternative fuels

As well as electric cars, there are other low emission fuels on the market, although they can sometimes be a little hard to find at the pumps.

Liquefied petroleum gas (LPG), for example, produces fewer emissions of carbon dioxide, hydrocarbons, carbon monoxide and nitrous oxides than both petrol and diesel

Compressed natural gas (CNG), meanwhile, is more efficient, operates quietly and emits fewer toxic chemicals than conventional fuels. Many petrol and diesel engines can be converted to run on CNG.

Bio-diesel, another alternative fuel, has been causing heated debate among politicians and environmentalists for some time. It is produced from renewable sources such as sugar beet, rapeseed, palm oil and sunflower oil, and it is carbon-zero (as all the carbon dioxide it produces was absorbed in the first place by the plants used to make it).

It sounds like the perfect green fuel. However, there are concerns that vast amounts of rainforest and arable land are being cleared to grow the raw materials, contributing to food shortages and deforestation around the world – hardly environmentally-friendly credentials.

At the moment, bio-diesel is only available at a few petrol stations, but it usually costs less than petrol or diesel. Otherwise, you can get it free by collecting used oil from restaurants and filtering it yourself, if you know how. The Centre for Alternative Technology in Wales runs courses if you're keen to find out.

Choosing a green car will not only help the environment, but it will cost less to run and insure. The range of green options available is improving all the time, so choose wisely, for the sake of both the planet and your wallet.