Green myth FAQs

Can a diesel engine run on chip fat? Are alternative fuel cars harder to drive? Find out now.

Read our essential guide to all the main green motoring myths and questions.

Can a diesel engine run on chip fat?

Surprisingly, yes. All diesel engines can run on a mixture of at least five per cent vegetable oil (B5 biodiesel) and 95 per cent diesel, with many older diesels able to run entirely on chip fat. Be careful to use oil rather than fat, and ensure the oil is filtered from any solids.

Make sure you check with your car manufacturer whether your engine can run on this kind of biodiesel first, otherwise you may void its warranty. Also be aware of your motor’s new smell of chip shops wherever you go.

The advantage is, of course, the huge amount of money you’ll save on fuel. Vegetable oil is exempt from tax excise duty.

Do green cars have weaker performance than petrol cars?

No. The common misconception “all green cars are weak cars” is simply not true.

Many look at how slow some electric cars are, and assume all other green cars run at similar performance. The fact is, whether they run on biofuel, hydrogen or electricity, green cars are improving all the time. One day they’ll be the main source of fuel for vehicles, since they’re renewable, and until then the only way is up.

Read our green alternatives to petrol supercars article for further proof.

Can electric cars be charged in an ordinary mains socket?

Yes. Charge time varies however, and can take anything from four to ten hours in length, depending on the car model and its batteries. And you’ll legally need to be parked off-road.

There are also special charging stations at certain garages and manufacturer service stations, which charge electric vehicles at a much faster rate.

Some have units which act as a bridge between the car and the mains. Make sure your socket is protected from power surges and fitted with a circuit breaker. If you’re in doubt, contact an electrician. Sometimes a socket independent of your fuse board may need to be installed.

Does driving an environmentally-friendly car make me exempt from tax?

Not unless you’re driving a truly green machine. It all depends on your vehicle’s tax band – the lower the carbon dioxide it emits, the less tax you’ll have to pay.

Band A vehicles emit less than 100 grams per kilometre and are thus exempt from tax. This makes all electric and hydrogen vehicles tax-free since they don’t have any CO2 emissions.

Check out our car tax guide for full details on vehicle excise duty and how much you have to pay.

What about the London congestion charge?

Electric cars are exempt, as well as other alternative fuel vehicles - but ones which meet the detailed requirements.

Read the London Congestion Charging document for more information.

Are alternative fuel cars harder to drive?

No, but there are other implications which set them apart from motors with normal petrol and diesel engines.

Electric and hybrid vehicles are considerably quieter than their petrol and diesel cousins, so bear this in mind when travelling through areas with lots of pedestrians who might not hear you approaching.

Electric vehicles also tend to accelerate faster than fuel-based cars because they have no clutch. Driving and operating wise however, there is no real difference.

Do hybrid vehicles have to be recharged?

No – they have a rechargeable battery, but this is automatically charged in-car by kinetic energy, which is generated when braking.

Plug-in hybrid vehicles will be able to charge from a mains outlet however, to extend their electric-only driving mode. These are currently in production and won’t be available for a few years’ time.

Are alternative green fuels easy to find?

At the moment, bioethanol, biodiesel and hydrogen aren’t as easily available as petrol or diesel is in normal petrol stations. However, they’re increasing in use and should become more widely accessible over the next few years.

You can find the nearest alternative fuel station to you from the Energy Saving Trust’s UK fuel map.

Do I need to modify my car to use bioethanol?

It depends on the rate of biofuel you’re after. A normal engine can handle up to five per cent bioethanol and 95 per cent petrol – any more and a specific flexi-fuel engine will be needed to cope with larger intakes of bioethanol.

Installing a new engine may be difficult and expensive, but there are more bioethanol-powered cars creeping onto the market.

Bioethanol can come in other forms too – E10, E15, E20, E85, E95 and E100, where the number is the percentage of bioethanol to petrol. E85 is a common high blend, and E100 contains no form of petrol whatsoever.

Many diesel vehicles can run on higher mixes of biodiesel – but check with your manufacturer first – your engine may not need altering.