Most efficient electric cars unveiled: BMW i4 and Tesla Model 3 top

Electric vehicles are generally believed to have better environmental benefits than petrol and diesel cars – but which EVs are the most efficient?

A new ‘E-Rating’ has been launched which ranks every model for sale in the UK by how efficiently they use electricity, claiming there is a £500 gap in annual charging costs between the best and the worst cars.

Of the 49 models already rated by Electrifying.com, the BMW i4 and Tesla Model 3 have the highest A++ rating, while at the bottom of the list is the Mercedes EQV MPV – the only car with the lowest E rating.

Most Efficient EVs Revealed: New E-Rating System Launched to Tell Consumers How Fuel-Efficient Different Electric Models Are, with Tesla Model 3 scoring a top score of A++

BMW's i4 sedan, which has a range of up to 365 miles, has also received the highest rating in the new scale

BMW’s i4 sedan, which has a range of up to 365 miles, has also received the highest rating in the new scale

The website, which provides information and advice to electric car buyers and existing owners, says the purpose of the E-Rating is to give consumers clarity about which electric cars will be better off in their bank account.

While motorists understand the concept of miles per gallon for gasoline and diesel engines, there is no industry standard figure to help drivers understand the overall efficiency of an electric car.

Because the public is well aware of energy labels, from washing machines to property EPC scores, the E-Rating is a similar scaled system to inform buyers which cars are ahead of others.

The rating of each EV is calculated using an algorithm that involves a number of factors.

The E-Rating scale works the same way energy labels do for everything from washing machines to property EPC ratings

The E-Rating scale works the same way energy labels do for everything from washing machines to property EPC ratings

This includes how good electrical power is converted into kilometers on the road, the rate at which the battery can be recharged and whether it includes features to minimize power consumption, such as heat pumps, intelligent braking energy recovery and air conditioning preconditioning.

Until now, only the BMW i4 – priced from £51,905 and with a range up to 365 miles – and Tesla Model 3 – priced from £42,990 and with a range between 305 and 360 miles (depending on specs) were worthy of the maximum A++ ratings for electric vehicles currently on sale in the UK.

Proof it’s not just about price, the £100,000 Mercedes EQS luxury saloon gets the same A+ rating as the dinky – and cheap – Citroen Ami (around £6,000) and Renault Twizy (around £12,000) four-wheelers, and Seat’s £20,000 (including from the £2,500 Plug-in Car Grant) Mii Electric City Car.

These four vehicles are among the 13 models with an A+ rating, and another 14 that perform well enough to earn an A.

The Mercedes EQS, which starts from £100k, has an A+ E-Rating

Citroën's £6,000 Ami city car - with a range of just 46 miles - gets the same A+ rating

The E-Ratings don’t factor in vehicle price, so the luxury Mercedes EQS saloon (left) – which starts from £100,000 in the UK – has the same A+ rating as the £6,000 Citroen Ami four-wheeler (right)

At the other end of the scale, the Mercedes EQV passenger car – which has a range of 213 miles and costs a whopping £71,645 – is the only vehicle with the lowest E-rating, while the Audi e-tron (from £60,560) and Mercedes EQC (from £64,925) luxury SUVs were classified D.

Based on miles per kilowatt hour alone, Electrifying.com calculated the cost difference to bridge 10,000 miles between the A++ rated BMW i4 and the E-class Mercedes EQV at £580.

Although the Mercedes passenger car and the BMW family saloon do not compete in the same class, there are still major differences between electric cars that fall into the same segment.

For example, a Tesla Model Y (rated A+) costs £176 less over 10,000 miles than a Volvo XC40 Recharge, based on the calculation.

In addition to the added cost, owners of the least efficient cars will have to wait much longer for a charge – partly because they use more energy to move, but also because they can take charge at a slower pace.

E-Ratings for electric cars for sale in the UK

Tesla Model 3: A++

BMW i4: A++

Hyundai Ioniq: A+

Citroen e-C4: A+

Fiat 500e: A+

Hyundai Kona Electric: A+

Mercedes EQS: A+

Kia EV6: A+

Peugeot-e208: A+

Seat Mii: A+

Tesla Model Y: A+

Opel Corsa E: A+

Citroen Ami: A+

Volkswagen ID.3: A+

Renault Twinzy: A+

Hyundai Ioniq 5: A+

Audi Q4 e-tron: AN

BMW iX3: AN

DS3 Crossback: AN

Ford Mustang Mach e: AN

Kia e Niro: AN

Kia Soul: AN

Peugeot e2008: AN

Renault Zoe: AN

Skoda Enyaq: AN

Smart ForTwo EQ: AN

Tesla Model S: AN

Tesla Model X: AN

Opel Mokka: AN

Volkswagen ID.4: AN

Audi etron GT: B

BMW i3: B

Mercedes EQA: B

MG MG5 EV: B

MG ZS EV: B

Nissan blade: B

Pole star 2: B

Volvo XC40 Charging: B

Honda-e: C

Jaguar i Pace: C

Lexus UX300e: C

Mazda MX-30: C

Porsche Taycan: C

Rimac Nevera: C

Citroen e-Spacetourer: C

Opel Vivaro e: C

Audi etron: NS

Mercedes EQC: NS

Mercedes EQV: E

Source: Electrifying.com

For example, a Vauxhall Mokka can be driven twice as fast as a Mazda MX-30, while the latest Hyundai and Kia models can add 60 miles of range in less than five minutes.

With electric vehicle sales booming, the total number of electric vehicles on the road in the UK will exceed 300,000 by the end of 2021.

Extrapolated nationally, the cost difference between charging the most and least efficient cars represents an estimated £155 million a year in electricity costs, claims Electrifying.com.

The Mercedes-Benz EQV people carrier is the only EV to receive the lowest E-Rating with an E rating to date

The Mercedes-Benz EQV people carrier is the only EV to receive the lowest E-Rating with an E rating to date

The Audi e-tron premium SUV - which costs just over £60,000 - has an efficiency rating of D.  got

The Audi e-tron premium SUV – which costs just over £60,000 – has an efficiency rating of D. got

The Mercedes EQC - a rival to the Audi e-tron in the luxury SUV sector - also received a D rating from Electrifying.com

The Mercedes EQC – a rival to the Audi e-tron in the luxury SUV sector – also received a D rating from Electrifying.com

The new efficiency rating is supported by AA President Edmund King.

Commenting on the arrival, he said: ‘Anything that helps consumers decide in simple terms the most efficient electric car for their needs can only be positive.

“Drivers must research a range of factors based on their individual needs before choosing a vehicle type, and efficiency is an important factor for many.”

Ginny Buckley, founder of the EV-specific website, said the assessment is not just about educating consumers about which electric models are the most fuel-efficient, but also spurring manufacturers to make improvements.

‘I’m surprised that we don’t have an effective efficiency standard for electric cars, like we have in other sectors; but we have tried to rectify this.

“Since electricity costs less than petrol or diesel, it’s easy to dismiss the efficiency of electric cars and think it’s not important. But the costs of a less efficient model can quickly add up.

‘Perhaps more important is that an electric car that is more economical, goes further and spends less time charging, which means more convenience for the consumer.’

> When will car manufacturers go electric? Read our comprehensive guide to each mainstream brand, how many EVs it currently offers and when it plans to end production of petrol and diesel vehicles

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