Green Machines | PHEVs thirstier than claimed and potential softening of ZEV mandate

• Autotrader says government should stick to its guns on the ZEV mandate targets for electric cars
• Study suggests plug-in hybrid vehicles use way more fuel in real-world driving than claimed in official efficiency tests

Will the ZEV mandate be softened?

In case you missed it and all (we’ll forgive you if you have!) the ZEV mandate is the carrot for consumers and stick for manufacturers to increase the proportion of zero-emissions cars sold each year. By the end of 2026 manufacturers need a third of the cars they’ve sold to have been fully electric or face penalties, that increases to 38 per cent next year and then to 80 per cent by 2030 before new internal combustion sales end in 2035.

That’s the simple version! In fact, the ZEV mandate walks the line between (sometimes) competing ambitions of consumers, manufacturers, retailers, regulators, energy suppliers and more. Generally, the government wants to increase EV take-up while manufacturers are looking for more flexibility to account for fluctuating demand for electric models.

Conflicting messaging doesn’t help, the government on one hand encouraging buyers into EVs with the electric car grant while seemingly penalising them with the other with the pending introduction of ‘pay-per-mile’ taxation to recoup some of the tax revenue lost in the reduced demand for petrol and diesel. At the time of writing, there is speculation the government review into the ZEV mandate will backtrack on the 80 per cent split by 2030 in an apparent concession to manufacturers. A move that would disappoint environmental campaigners, https://www.edie.net edie.net claiming a modest reduction to 70 per cent would increase CO2 emissions by more than burning all the gas in the Rosebank field for which drilling approval has just been given. Charging providers also oppose any cut, saying it would reduce demand for home installations and, with it, EV uptake.

“If the government wants the EV transition to succeed, it must take this opportunity to provide a consistent, supportive roadmap, not a set of mixed signals that confuse consumers,” says Autotrader’s Chief Customer Officer Ian Plummer. “Pick a target and then stick to it.”

Plug-ins not as green as claimed

Plug-in hybrids have been a convenient – and flexible – way for manufacturers and drivers to transition to electric without fully committing to battery-only power. They’ve also been heavily incentivised by regulators and taxation, especially for company drivers. Official fuel consumption tests also favour them, meaning manufacturers can claim triple-digit mpg figures beyond the wildest dreams of regular combustion-engined cars, mild-hybridsor ‘self-charging’ hybrids lacking the facility to plug in.

But a study confirms what has long been suspected, namely that in real-world driving these claims simply don’t bear out and plug-ins – or PHEVs – use a lot more fuel than advertised. An investigation by a body called the Fraunhofer Institute seemingly analysed onboard fuel consumption data from a million PHEVs and found the internal combustion element of the powertrain was firing up more often than expected, whether that be for more power to the road or to charge the battery.

Our experience of running various PHEVs on long-term test suggests the fuel consumption – and therefore eco friendliness – very much depends on usage, and especially charging habits. If you have a driveway, a https://www.autotrader.co.uk/content/features/getting-a-home-ev-charger-installed home charger and can plug in each night it’s entirely possible you could do much of your regular driving on electric power alone, without using any petrol at all. But not everyone has this facility – or indeed inclination – and a PHEV with an exhausted battery can prove a lot less efficient.

Things are improving, bigger batteries and improved technology in the latest generation of PHEVs meaning they spend more time on electric power. But if you really want to go green fully electric remains the safer bet.