Range-extender – EREV
The key difference between a PHEV and an EREV is that an EREV is an electric car whose petrol or diesel engine operates not as a source of direct drive to the wheels, but as a form of onboard generator to ensure the battery that powers them never becomes fully depleted.
It works in the same way that a full EV works, with electric motors powering the driven wheels and regenerative braking feeding kinetic energy back into the car’s power banks to help sustain the batteries. Most EREVS are also switchable, meaning that you can choose when to use the pure electric range via a ‘hold’ button rather than drive it until it runs out and swaps over automatically – making it an ideal option for driving in areas where pure electric only is allowed, or will be in the future.
The first commercially available EREV was the Chevrolet Volt, revealed in 2008 and launched in production form at the 2010 Detroit Auto Show as GM’S Great White Hope. It was followed by a European Volt (sold in small numbers in the UK) and its sister car, the Vauxhall or Opel Ampera. The Volt was also sold for a short while in Australia as the Holden Volt, though in a country where the fuel cost per gallon is the same as it is per litre in the UK, its appeal was somewhat limited given the steep purchase price.
After the Volt came the BMW i3, sold as both a pure EV and a range-extender using almost identical technology to that offered by GM, the key difference being that by 2013 when the i3 arrived in the UK, battery technology had advanced sufficiently to give it a pure electric range of around 20 miles more than the Volt’s 30 miles, which may not sound much but is more than adequate for over 75% of commuters.
Indeed, comedian and talk show host Jay Leno covered over 25,000 miles in his Chevrolet Volt before he had to put any petrol in it, and even then it was only to use up the fuel to stop it going stale. He was (and remains) one of the technology’s biggest advocates. Another is Sadiq Khan, Mayor of London, who has incentivised taxi drivers to take up the new Coventry-made London Taxi because of its switchable EV capability, which allows cabbies to drive to the city in range-extender mode and then turn on the cab’s electric mode when on duty in the capital.
Its popularity is slowing down in the passenger car market, though, as manufacturers switch to PHEVS as a more affordable and simpler alternative, which can be sold to consumers with a better margin.
Because EREVS are generally more expensive to build than PHEVS, the technology therefore appears to have more of an immediate future in the commercial vehicle industry. TEVVA in Europe and Via in the US are two of the truck manufacturers that are developing commercial versions of the technology, while LEVC, the company that makes the London Taxi, is also due to launch a delivery van later this year, targeted at operators in and around the capital.
But don’t write EREV off in the car market just yet. As battery technology constantly improves and more and more car makers develop Ev-specific platforms that don’t rely on direct-drive from combustion engines, it’s not yet the EV market’s Betamax. Far from it, in fact.