A new report from Swiss research company Empa concludes that a petrol-engined car must consume between three and four liters per 100 kilometers (or about 70 mpg) in order to be as environmentally friendly as the electric-car that was studied, powered with Li-ion batteries and charged with a typical European electricity mix (oil, coal, nuclear, hydro).

The study shows that the electric car’s Li-ion battery drive is in fact only a moderate environmental burden. At most only 15 per cent of the total burden can be ascribed to the battery (including its manufacture, maintenance and disposal). Half of this figure, that is about 7.5 per cent of the total environmental burden, occurs during the refining and manufacture of the battery’s raw materials, copper and aluminium. The production of the lithium, in the other hand, is responsible for only 2.3 per cent of the total.

A full pdf of the report is available here with the full supporting information here.