There have been fears that a move towards electric driving would require additional generation capacity from the various national grids. However, a new analysis suggests this will not be necessary if off-peak charging is successfully introduced.
Oscar van Vliet of the International Institute of Applied Systems Analysis, along with colleagues at Utrecht University, states that if off-peak charging is introduced then there will be no need for additional generation capacity – and that is even in the event of a 100 per cent switch to electric vehicles.
Printed in the Journal of Power Sources, his study looks at the efficiency and costs of current and future electric vehicles as well as their impact on electricity demand. The team looked at a compact five-seater in their analysis and compared electric vehicle configurations to those of a petrol car, diesel car, parallel hybrid car and series hybrid electric vehicle. They assumed that petrol engine generators in series hybrids and parallel hybrids have the same efficiency relative to diesel generators and assumed a shift from current central motor drivetrains to wheel motor drivetrains from 2015 onwards because of the higher efficiency of wheel motor drivetrains.
Their findings show that uncoordinated charging would increase national peak load by seven per cent at a 30 per cent penetration rate of electric vehicles, while the household peak load would increase by 54 per cent which might exceed the capacity of existing electricity distribution infrastructure. However, at 30 per cent penetration off-peak charging would result in a 20 per cent higher and more stable base load with no additional peak load required.
In addition, greenhouse gas emissions from electric driving depend mostly on the fuel type – coal or natural gas – that is used in the generation of electricity for charging and typically range from 0g/km using renewables to 155g/km using electricity from an old coal-based plant.
It also found that the total cost of ownership of current electric vehicles is uncompetitive when compared with regular cars and series hybrid cars by around €800 a year. However, the total cost of ownership of future battery powered electric cars is at least 25 per cent higher than that of series hybrid and regular cars with the cost gap remaining due to the high price of batteries.
