Electric car in real-world test: High-speed driving consumes more range than heating or air conditioning

The Canadian telematics specialist Geotab analyzed around three million trips for this purpose. The company, which has been offering fleet management systems since 2000 and digitally monitors more than five million vehicles worldwide, wanted to find out how strongly various factors affect the energy consumption of electric cars. "Many drivers try to delay switching on the air conditioning in warm weather in order to save energy. But our data show that high speed is more detrimental to range," says Charlotte Argue, who heads sustainability at Geotab.

The results are clear: From as low as 80 kilometers per hour, the energy demand increases more due to speed than due to the air conditioning. The reason is a fundamental law of physics. Beyond a certain speed, aerodynamic drag dominates consumption, and it increases not linearly but with the square of speed. Anyone who drives twice as fast needs four times the amount of energy to overcome air resistance.

Geotab cites the case of an electric van with a 65-kilowatt-hour battery: At a steady 80 km/h it manages around 230 kilometers. If the driver increases speed to 97 km/h, range drops to 195 kilometers. At 112 km/h it is down to just 166 kilometers. Those who drive just below the motorway advisory speed of 130 km/h have to make do with about 142 kilometers — a loss of around 38 percent compared with 80 km/h.

For passenger cars with a lower, sleeker body, the effect is less pronounced but still noticeable. An electric sedan that can still cover 446 kilometers at 80 km/h only manages 322 kilometers at 128 km/h. That corresponds to a reduction of one quarter.