Audi has commenced testing of its new A2 e-tron and is already on the way to making it one of its most efficient models to date. In fact, Audi says that the A2 e-tron has a drag coefficient of 0.24, which matches that of the low e-tron GT electric sports car. Photos: PA MediaAlready, the German brand has said that the A2 e-tron is the ‘most efficient Audi of all time’ according to WLTP measurements. In recent tests, the A2 e-tron managed a score of 4.85mi/kWh, extracting a high level of distance from the amount of energy used. Underneath, the A2 e-tron has a relatively compact electric battery.