Depends where you charge it. My car is averaging about 3.3 miles per kWh (kilo Watt Hour) of electricity So, 300 miles divided by 3.3 would give me the amount of electricy in kWh, 300/3.3 = 91kWh Charging at home I pay 7p per kWh so 91 x 7p =£6.37 Charging at a charger awy from home it would cost anywhere from 30p to 90p per kWh A typical Tesla or Ionity charge off peak would cost about 41p per kWh, so 91 x 41p =£37.31 If a full BEV (Battery Electric Vehicle) suits you needs and you can charge at home it’s a no-brainer as far as economy is concerned. My previous petrol Ateca did 36mpg, that was costing me £80 to £120 a month, the Enyaq I have is costing me £12 to £14 a month.
Many thanks