The driving force of automotive efficiency

Recent figures from the Society of Motor Manufacturers (SMMT) reveal that last year new cars were 18 per cent more efficient than older cars on the road.

In fact, in 2011 46.8 per cent of new cars achieved sub 130g/km CO2 emissions, which in turn helped lower the UK’s average CO2 emissions figure to 138.1g/km. This is a 4.2 per cent drop year on year.

Also, last year 65,000 vehicles in the UK qualified for road tax exemption by emitting less than 100g/km CO2 emissions.

But what is at the forefront of these CO2 improvements?

Eco-signatures

Eco-signature is the name given to a petrol or diesel engine in a manufacturer’s range that is particularly efficient. Each manufacturer has its own unique name for its eco-signature. For example, Mazda’s eco-signature is called Skyactiv.

Skyactiv uses a combination of efficient engine technology and lightweight materials to reduce emissions. Mazda’s new CX-5 model uses Skyactiv which helps it emit sub 120g/km CO2 emissions and return up to 62.8mpg.

Mazda CX-5 prices start from £21,395.

Hybrid

Hybrid vehicles use a petrol or diesel engine combined with an electric motor.

Hybrids include the new luxurious Citroen DS5 diesel. With the use of its Hybrid4 powertrain the DS5 can emit emissions as low as 99g/km, yet deliver a surprising power output of 200bhp.

Citroen DS5 prices start from £22,400.

Electric

Electric vehicles (EVs) are exactly what they say on the tin. They are powered using electrical energy acquired from charging points.

The new Renault Twizy is one of the latest electrical additions to the market. With zero tailpipe emissions it is exempt from both road tax and the London congestion charge, which can prove useful as its snug size is perfect for city driving.

Renault Twizy prices start from £6,690.

Extended range electric

An Extended range electric vehicle (E-REV) is neither a hybrid nor an electric vehicle.

An E-REV uses batteries that are charged via an electrical charge point to power its motors. However, when this battery runs out of power, a small on board petrol engine kicks in to charge it up again.

E-REV vehicles include the Vauxhall Ampera which with the use of its frugal powertrain can achieve up to 235.4mpg.

Vauxhall Ampera prices start from £28,955 (after £5,000 government grant)