‘No emission’ advantage of electric cars is a myth

 

Sir, – There is a popular misconception that electric cars cause no greenhouse gas emissions. While this is true while they are in use, the generation of the electricity to charge the batteries causes emissions. One cannot say that a renewable source supplies the electricity unless it is a dedicated renewable generator at the place where the car is normally kept.

In Ireland the electricity generated from all sources feeds into the national grid. One must assume that the system is run to maximise the use of the most efficient generation plants and those with the least amount of emissions first and the least efficient with the highest emissions (coal-burning stations), only when no other resource is available, for incremental loads. Charging of electric car batteries falls into this category of incremental loads

There are many factors which must be considered in calculating the overall efficiency of conversion of input energy to useful energy in any system. For coal-burning plant, the useful output to power a car will at best be similar to directly burning fuel in a car engine – ie 25 per cent to 30 per cent of the input energy – and will probably be worse. Therefore, the “no emission” advantage of electric cars is a myth. – Yours, etc,

BRENDAN MURPHY,

Sandycove, Co Dublin.