Eco driving: All you need to know

According to some estimates, we only have 40 years’ worth of oil reserves left – in which case petrol and diesel prices will keep rising as supply dwindles. And this is part of the drive behind the growing popularity of vehicles that use alternative fuel.

Others argue that there’s actually a huge amount of oil waiting to be extracted, but even if that’s true, environmentalists say we still need to be weaned off fossil fuels because of the damage our CO2 emissions are having on the environment.

In either scenario, there’s a compelling argument for vehicles that use alternative fuels. Here’s a look at how they stack up against petrol and diesel engines and whether you’ll eventually be trading in your car for something more environmentally friendly.

Electric cars

Some say they’re twice as clean as fossil-fuel engines, but others argue that it depends on how the electricity powering them is generated.

Electric cars are technically zero-emission vehicles, but if the electricity they use is generated by a coal-fired power station, then the vehicle is still creating CO2 emissions, even if it’s not directly.

A Norwegian University of Science and Technology study reported that when coal was burned to produce power for electric cars, greenhouse gas emissions rose considerably.

On the flip-side of that, for every electric car on the road there’s one less burning petrol or diesel, and if we all switched then oil refineries would theoretically pump out less CO2 as well.

Electric cars don’t get much cheaper than the tiny Renault Twizy (pictured) at just under £7,000 – but you have to rent a battery at £45-£60 a month, depending on your mileage and contract length.

The lithium ion battery only has a range of between 30 and 70 miles though, and takes 3.5 hours to charge. A full charge can cost as little as £1.50 (if charged overnight using a three-pin socket in your home), but given its limited range you’ll probably be charging it once a day, if not more.

If you charged it once a day, however, and factored in the battery rental, running costs could reach £90 to £105 a month. I spend about that on my 1.2 petrol Volkswagen Polo and I get about 350 miles’ range from a full tank.

Electric vehicles are exempt from road tax and congestion charges, however. The government also offers grants of up to £5,000 for some electric vehicles (the Twizy doesn’t make the cut though).

At the other end of the scale, the Chevrolet Volt (from £35,255) has a far greater range - 300 miles thanks to its on-board petrol-powered generator and an ample top speed of 99mph. You can get a full battery in four hours, which at 10.8kWh should cost you around £1.50 to charge too.

When the Volt’s battery runs out, however, a petrol-powered generator kicks in – so you’ll need to keep that topped up too.

The combination of the electric drive train and petrol generator gives the Volt a staggering combined economy of 235.4 miles per gallon.


Hybrid cars, which have traditional combustion engines and an electric motor, improve fuel economy by 20 to 25% while cutting CO2 emissions.

There are far more hybrids to choose from than electric vehicles, from manufacturers such as Honda, Toyota, Lexus and Peugeot, and prices start at around £15,000.

The Toyota Prius Plug-In is perhaps the most economical of the hybrid crowd, with a combined economy of 134.5mpg thanks to its combination of a petrol engine and additional batteries that you can charge at home. It doesn’t come cheap though, at £28,245 after the government has chipped in £5,000.

The Prius has an electric driving mode for short journeys, which means you won’t use any of your petrol and your car won’t be coughing out any CO2.

The Toyota Yaris Hybrid T3 is almost half the price at just under £15,000 and has a combined economy of 80.7mpg thanks to its petrol engine and electric motor/battery combination.

Its tank is just shy of 8 gallons, which means you could (according to Toyota’s figures) get around 645 miles out of a full tank. Of course mpg figures shouldn’t be taken at face value.

Both cars’ CO2 emissions are well below the car tax threshold of 100g/km and so you won’t pay any car tax or congestion charges.


An LPG car can cut 40% off your motoring fuel bill, and you can even convert the car you have right now to use the cheap fuel.

Liquid Petroleum Gas is around half the price of petrol and diesel. When Les Roberts test drove an LPG car for a week, its economy worked out as 13p per mile – almost half the cost of running his Rover 25!

LPG vehicles also put out 20% less CO2 than conventional engines, but unless your CO2 emissions drop below 100g/km you won’t see any tax benefits.

It costs around £1,500 to £2,000 to convert to LPG, but the modification shouldn’t affect your car insurance premiums and at half the price of fuel and diesel, you could recoup the cost in a couple of years, depending on your mileage.

Fuel efficient petrols and diesels

If you’re not ready to part with conventional engines just yet, the good news is that petrol and diesel engines are becoming more efficient all the time.

For example, the 1.2TDI diesel Volkswagen Polo BlueMotion is capable of 80.7mpg (combined, according to VW).

As for prices, you won’t be paying a premium for special engine/fuel types and there’s no battery to hire.  The aforementioned Polo starts at around £16,000 and you won’t pay car tax or congestion charges thanks to its saintly sub-100g/km CO2 emissions.

And of course you’re not limited in range or speed in the same way as you are with an electric car, you won’t have to fill up as frequently as you do with an LPG car and you won’t pay the hybrid premium.

Please note: Any rates or deals mentioned in this article were available at the time of writing. Click on a highlighted product and apply direct.

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