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  • Writer's pictureSustainable Overton

Low Carbon Motoring

Energy has to come from somewhere: for an internal combustion engine it’s the petrol or diesel you fill the tank with, with an electric car it’s the electricity used to charge the batteries. An average car internal combustion engine achieves an efficiency of around 25-35% meaning that up to 75% of the energy within the fuel is wasted.

The efficacy of an electric car depends very much on where the electricity comes from. The best fossil-fuelled power stations can achieve efficiencies of 45-60%, whereas electricity produced from a hydro plant, a wind or solar farm requires no fossil fuel input other than in their initial construction. So if you travel by electric car, your carbon footprint will therefore depend largely on your electricity supplier.

The UK has committed to ban the sale of new petrol, diesel or hybrid cars by 2035.

Electric Cars – the main points to consider


At the time of writing the cheapest electric cars available in the UK cost just over £20,000. A handful of manufacturers produce small cars in the £20-25,000 bracket with a claimed range of up to 160 miles.

Battery life

The capacity of the battery will decline with use. Typically, this could be by 20-40% over 10 years and the cost to replace a battery could be so high that it's uneconomical to do it. Some manufactures offer a warranty on battery capacity, and typically they will offer replacement if the capacity drops below 80% during the warranty period. As battery technology improves, we can expect to see increased battery service life. Some recent studies have found that the battery capacity in higher end makes after 10 years was within 15% of the capacity when new.


The real life range of an electric car will depend on how it is driven, the ambient temperature and the use of heating or air conditioning. One thing you can be sure of is that the range will be less than that claimed by the manufacturer. Typical real-world ranges are about 80% of the claimed range. For those of us who make long journeys there are at least 5 manufacturers currently producing cars with a claimed range of over 250 miles.


The charging time will depend on the capacity of the battery and the size of the charging supply. Charging at a public fast charger will be very much quicker than charging at home using a 13a socket. Some smaller cars can achieve 80% charge within 30 mins at a fast charger whereas charging at home can take 8 hours or more.

The number of public charging points is expanding rapidly and there are several apps which show you where the nearest one is to you. Unfortunately manufacturers of electric cars have not yet agreed on a single standard design for the charging plug.

At the moment, installers of home chargers are eligible for an “Office for Low Emissions” grant of £350 meaning that the cost to fit a home charging point can be under £400.

The government has recently announced a doubling of its funding for EV charging to £10 million to go towards installing an extra 3,600 charging points across the UK.

The government also hopes to produce a publicly accessible charger monitoring app which could show whether facilities are in use or out of order.

Running costs

The cost of the electricity used to charge an electric car will dictate its running cost. Using public charging points is generally more expensive than using a domestic supply but even then, the cost per mile of electric travel is likely to be about a third of the cost when using petrol. The Energy Savings Trust have calculated that charging an electric car with a range of 100 miles could cost between £4 and £6 if you're charging at home, whereas the cost of fuel to go a similar distance could be between £13 and £16.

Electric cars do require servicing at regular intervals, although the cost is typically less than a conventional car because they do not consume air filters, oil or spark plugs.

Electric cars are exempt from vehicle tax and are not currently subject to the London Congestion Charge.

If you're buying new, many manufacturers offer a scrappage trade in, which can be up to £5000 but varies with the make and model of new car you are buying.

The government also offer £3,500 towards the cost of a new electric vehicles (battery only – hybrids are excluded), known as the Plug in Car Grant scheme.

Some towns and cities currently offer free parking for electric vehicles.

By Jane in the Transport Group for Sustainable Overton.


Office for Low Emissions vehicles eligible for plug in grant -

Office for Low Emissions grants for charger points -


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