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Electric vs Petrol cars – Real efficiency compared

Electric vehicles (EV) are more efficient than internal combustion engines (ICE) as these technologies lose less energy when converting stored power into propulsion.

Petrol and diesel autos lose between 74-85% of their original potential during the conversion of fuel to drive through heat produced in the engine, pumps, cooling systems, and mechanical friction, revealed a Yale Climate Connection report.

In comparison, EVs do not need to convert energy from one form to the other and are therefore more efficient. Power is still lost during the charging process, as well as for cooling, steering, and drivetrain and auxiliary components.

However, this only eats around 31-35% of the charge, with 22% gained back through regenerative braking. As such, EVs only lose approximately 13% of their original energy when turning electrons into forward motion.

What this means in the real world

Numbers and percentages mean nothing if you can’t relate them to real-world experiences, and South Africa’s most affordable EV, the Mini Cooper SE, offers the perfect comparison.

According to MasterDrive, it costs approximately R177 to charge the electric Mini’s 32.6kWh battery from 0-100%, depending on the cost per kWh, which affords the owner a range of around 217km.

On the other hand, the petrol-powered Mini Cooper S with a comparable output to the SE and a fuel consumption of 6.0l/100km costs roughly R283 to travel the same distance.

“Assuming the real-world fuel consumption is slightly higher than the claimed and depending on how the vehicle is driven, it is safe to assume that the cost is somewhat higher than this,” said Eugene Herbert, MasterDrive CEO.

“Thus, again, the EV performs more efficiently. In comparisons between other vehicles there are variations, but ultimately, EVs are more efficient.”

The technologies have other clear benefits on a driver’s pocket, too, even if they are not as environmentally friendly as once thought.

During hours of heavy traffic, an EV consumes virtually no power to crawl through the congestion whereas fuel consumption in ICE cars picks up tremendously in bumper-to-bumper situations.

EVs also thrive during city driving where frequent stopping and acceleration are needed thanks to brake energy recuperation that recovers spent energy when slowing down and feeds it back into the battery.

“Ultimately, the proof is in the petrol,” said Herbert.

“It thus far shows that there are efficiency benefits to EVs that ICE vehicles struggle to compete with. Once EVs have price parity with ICE vehicles in South Africa, this will be even better.”

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