Testing by TU Graz, commissioned by environmental NGO Transport & Environment (T&E), has found that the newest generation of PHEVs emit significantly more CO₂ than claimed on city and commuter routes. Two years ago, T&E found the technology polluted significantly more than advertised on longer routes. The NGP says the new tests confirm that lawmakers should base taxes for PHEVs on their actual pollution and stop subsidizing their sale.

Three recent PHEV models, a BMW 3 Series, Peugeot 308 and Renault Megane, emitted more CO₂ than advertised when tested on the road even when starting with a full battery. The BMW emitted three times its official rating when driven on a typical commuter route, according to the tests. The Peugeot 308 and Renault Megane plug-in hybrids performed better but still emitted 20% and 70% more than claimed, respectively, despite the relatively short round-trip distance covered (55km).

In city driving, the Peugeot had just over half (53%) of the advertised electric range on a single charge while the BMW had only 74%. Only the Renault had the electric range claimed. However, with just 50km on a single charge and no fast charging, the Renault’s zero-emissions use on commuter routes across European cities will remain limited.

BMW has introduced new geo-fencing technology that automatically switches the PHEV to zero-emission electric driving in cities. However, when tested in the city of Graz, the BMW 3 Series switched on the engine twice. Tests also suggest that the BMW could be saving battery charge when outside cities in case of entry into geo-fenced areas. T&E said geo-fencing technology does not guarantee zero-emissions driving in cities and, potentially, risks increasing CO₂ emissions outside such zones.

Company cars make up 71% of new PHEV sales, and research shows they drive the vast majority of kilometers on the engine and are rarely charged. When tested with an empty battery, the BMW, Peugeot and Renault emitted 5-7 times their claimed CO₂ on the road. T&E said governments should end subsidies for PHEV fleet vehicles and tax them based on their pollution in the real world.

European countries spent around €350 million last year on purchase subsidies for PHEVs from BMW, Peugeot and Renault alone, T&E’s report finds.Consumers are also hit with the higher total costs of owning plug-in hybrids, compared to battery electric vehicles. On average, an EU driver switching from the Peugeot 308 plug-in hybrid to a Citröen eC4 would save €4,800 over four years while the electric Renault Megane would save €1,300 compared to the PHEV version, and owning a Tesla Model 3 instead of the BMW 3 Series PHEV would save €2,600.