Which bright sparks came up with this ridiculous proposal?

Even fast chargers for electric cars take about 30 minutes to provide an 80 per cent charge. Picture: John Devlin

The transport sector currently consumes about one third of total energy demand. Not all of this is due to cars, and electric vehicles can in principle be more efficient than internal combustion engine vehicles. However, one estimate suggests that if all Britain’s cars were electric, electricity production would have to increase by more than one third, from 337 TWh (terawatt hours) a year to 460 TWh. If this were to be supplied by nuclear power stations this would mean more than 18GW (gigawatts) of new capacity. Another estimate produced by National Grid suggests we may need as much as 30GW. Right now we have plans for only one new nuclear power station, Hinkley C, with a capacity of 3.2GW at a cost of at least £20 billion. So we would be looking at between five and ten more Hinkleys at £100bn and £200bn.

We could of course put up more wind turbines to generate this electricity. However, while a nuclear power station can run at 90 per cent of its rated capacity over the year, wind turbines can only manage about 30 per cent, so we would need 48GW, requiring 16,000 new wind turbines, another four times the current number. These would occupy about 19,000 square kilometers, equivalent to more than a quarter of the area of Scotland. And we would still need to build matching nuclear, gas or coal fired power stations so that we didn’t lose most of our transport when the wind didn’t blow for a few days.

Our electricity supply system is already creaking, with the closure of coal-fired stations the National Grid has been paying up to £2000 per MWh in emergency backup from diesel generators, about fifty times the normal wholesale cost.

Professor Jack Ponton FREng, Emeritus Professor of Engineering Scientific Alliance Scotland

It would seem irresponsible to propose increasing electricity demand until we are sure that current demand can be securely and economically fulfilled.

Then there is the logistics of charging all these cars. To refuel a petrol or diesel vehicle takes less than five minutes to fill a nearly empty tank. Filling stations are now being equipped with ‘fast’ chargers for electric cars. These take about 30 minutes to provide an 80 per cent charge, so we would be looking at long queues.

If you are able to park off road at home then your domestic supply can do the job overnight in about eight hours. But what if, like many city residents, you have to park on the street? It would be possible to install charge points along city streets, but at a cost since the electricity network was not designed with this in mind. The cost of upgrading both the local and national networks is likely to be very significant, and no estimates seem to have been made of it.

Indeed what will it all cost? An electric car put on the road today enjoys a straight grant of £4,500 from the taxpayer towards the cost of the car and the remission of road tax of typically £200 a year over its life. Instead of excise duty and VAT at £2.63 per gallon plus VAT at 20 per cent, electricity carries only VAT at five per cent. The annual loss of tax revenue for a car doing 10,000 miles a year would be nearly £1,000. Over an expected vehicle lifetime of 14 years taxpayers are generously giving electric car purchasers more than £18,000. If the same generosity were extended to the owners of nearly 30 million cars the bill would come to half a trillion pounds.

Until the issues of power generation, logistics and cost are resolved all cars being electric looks unachievable and unaffordable.

Professor Jack Ponton FREng, Emeritus Professor of Engineering, Scientific Alliance Scotland