How much energy does the vehicle consume per mile?
The first step is to work out how much energy the vehicle consumes per mile. This gives you the kWh/mile. Note, this will vary throughout the year with the use of air conditioning/heating.
Home charging cost
The cost per mile for home charging can be worked out by multiplying the employee’s cost per kWh by the number of kWh it takes per power the vehicle per mile (i.e. the kWh/mile figure from step one). Employees can provide a copy of their electricity bill to confirm the cost per kWh.
Public charging cost
If employees use public charge points, the cost per mile can be worked out in the same way using the vehicle’s kWh/mile.
The rate used to reimburse electric vehicle drivers can be a blended rate of home and public charging, taking any charging using company charge points into account. Or if an employee uses public charging for all/the majority of their business trips, the calculation can use the cost per mile for public charging first and then apply the home rate for any additional business mileage, again taking off any charging that has already been paid for by the company if they have used company owned charge points. Charge cards could also be considered for employees who rely heavily on public charging.