Here is how you tell if an electric car is more efficient than an ICE car, or not

We are all used to the fact that the fuel consumption of a petrol or diesel car is typically expressed in litres per hundred kilometres (l/100 km).

Quite simply, understanding and quantifying a ‘litre’ of any liquid comes naturally for anyone who can imagine holding a water bottle in their hands. Unfortunately, it isn’t so straightforward when it comes to electricity, and by that same extension - EVs.

An electric car doesn’t use fuel but gets its energy from a battery. The maximum amount of energy the battery can store (capacity) is expressed in kWh (kilowatt-hour).

Instead of the amount of fuel needed to cover a hundred km, the energy consumption of an electric car is expressed in the number of kilowatt-hours needed to drive a hundred kms (kWh/100 km).

Understanding kWh and EV efficiency?

Exciting as it is, EVs are still unknown territory for many, but the best way to understand an EVs efficiency is to calculate the ‘equivalent fuel consumption' of an EV to a regular internal combustion vehicle.

How? Well, we know a litre of petrol contains about 8.9 kWh of energy. Thus, if we compare this to the energy consumption of a particular EV, we can then obtain equivalent fuel consumption in l/100km.

As an example, we will use the Hyundai Kona which is offered in Malaysia with both EV and conventional ICE powertrains. In both cases, we will use the manufacturer-rated WLTP figures for comparison.

Hyundai Kona Electric e-Max

• Battery capacity: 64 kWh
• Power: 204 PS / 395 Nm
• WLTP combined energy consumption: 14.7 kWh/100km

Hyundai Kona 1.6L TGDI

• Engine 1.6-litre turbocharged, direct-injection
• Power: 198 PS / 265 Nm
• WLTP combined fuel economy: 6.2 litres/100km

If we convert those figures and compare them with the energy consumption of the Hyundai Kona EV (14.7 kWh/100 km divided by 8.9 kWh/litre), you have an equivalent fuel consumption of just 1.6 l/100 km.

Or nearly 4 times more efficient than the equivalent ICE-powered Hyundai Kona.  

Why is an EV far more efficient than an ICE car?

An important reason why an electric car uses far less energy compared to an ICE car is because an electric motor has an efficiency of about 90 – 95 percent, versus efficiency of between 35 – 40 percent in a typical ICE vehicle.

This means almost all the energy used by the motor is converted into motion to make the wheels turn. In a petrol or diesel engine, about a third of the energy is lost in heat alone.

With further developments in battery and motor technology, EVs powertrains are becoming more compact and thus lighter too which will have a positive impact on overall energy efficiency.  

Also read: Review: Hyundai Kona - Should you get this over the HR-V or CX-3?

Also read: Review: Hyundai Kona Electric e-Plus – Is it time to get an EV?