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Electric Cars - Cost of Electricity Per Mile

Using data on how much electricity is required to recharge an electric car battery and the car's battery range, we've calculated the cost of electricity per mile for nearly 500 electric cars.

We've then compared this cost per mile to the 5p reimbursement rate allowed tax free by HMRC and put the results into a table.

And it's not happy reading for most electric company car drivers.

Only four cars cost less per mile to recharge than the tax-free reimbursement rate.

All the rest will cost more in electricity each mile than HMRC allows.

And remember that the cost of electricity (at 28p per kilowatt-hour or 'KWH') doesn't include any contribution towards the standing daily charges most electricity suppliers charge customer's just for being allowed to draw electricity from the Grid.

What Does The Table Show?

In our table we've listed each car (column A), with the car's battery capacity (C) and battery range (D.

From this we've calculated;

• Column C: the manufacturer's battery capacity of the car (this is measured in kilowatts of electricity per hour);
• Column D: the distance ('range') the car could theoretically drive on a full battery charge;
• Column E: the cost to fully recharge the battery (£s) based on the capped 28p per KWH;
• Column F: the cost of the recharge per mile of battery range (pence per mile); and
• Column G: the difference between HMRC's 5p per mile tax free reimbursement rate and the actual cost per mile to recharge.

We've based the car's battery range on the Worldwide Harmonised Light Vehicles Test Procedure, the 'official' measure of electric car battery range.

The result in Column G of the table is an estimate for the difference between HMRC's rate of 5p.p.m. and the actual cost in p.p.m. to recharge the car.

A positive number shows that the 5p.p.m. is enough to cover the cost of electricity.

A negative number means that HMRC's tax-free reimbursement rate is insufficient to cover the cost of electricity used on each mile of business travel.

Remember ...

Electric vehicle recharge costs may be higher than the 28p per kilowatt-hour we've used, in which case electric company car drivers will lose more per mile.

Actual battery range will vary according to the equipment used in the car (e.g. using heaters/air conditioning reduce the actual range achievable).

Keep in mind too that the driving style of the car user will impact the number of times a car will need to be recharged each year and, for simplicity, we've assumed that the battery is discharged down to zero power then recharged back up to 100%.

Drivers of electric cars will usually recharge the battery well before it is completely discharged and may not charge it to 100% of capacity, but the overall effect of our calculation by battery capacity, range and total annual miles should still provide an accurate comparison.