Europe would like to review the very optimistic registration of plug-in hybrid cars

From 1.3 l/100 km to 1.6 l/100 km, this is the weighted fuel consumption of the Peugeot 508 Hybrid 225 e-EAT8 (plug-in hybrid or PHEV), in the WLTP mixed homologation cycle, and 4.1 l/100 km, the average consumption recorded by twenty drivers who registered it on the specialized site spritmonitor.de. None managed to reach the certification values.

Very optimistic consumption and emission values

Thus, in 2020, a study revealed that rechargeable hybrid cars consume in real conditions two to four times more than announced. Indeed, their homologated consumption and emission values ​​are particularly optimistic.

To better understand this difference, it is important to look at the calculation resulting in these values. To determine their fuel consumption and CO2 emissions for WLTP certification, plug-in hybrid cars are first drained of their battery in electric mode until their internal combustion engine (petrol or diesel) takes over. The result is an approved electric autonomy. Then, once their battery is discharged, the cars undergo tests similar to other cars to measure their fuel consumption and emissions.

Then, these consumption and emissions values ​​are weighted according to the electric range of the model. The larger it is, the more lawmakers believe the car will make a significant proportion of its journeys in electric mode. For our 508 Hybrid, whose electric autonomy is approved at 54 km, the WLTP approval estimates that its drivers will make on average around 70% of their journeys purely electric. This ratio is called utility factor (UF). The fuel consumption of a plug-in hybrid car of 1.5 l/100 km, for example, therefore hides a second consumption, this time of electricity, of x kWh/100 km.

Nevertheless, in reality, the drivers of plug-in hybrid cars charge on average much less than estimated by the certification protocols, in particular in the case of company fleets, which results in the consumption of gasoline and real pollutant emissions far higher than the theory.

Review the approval values ​​based on actual consumption

The EU is reportedly looking into the matter, reports Reuters, citing two sources familiar with the matter. Thus, the legislators would like to study the consumption in real conditions of the cars to establish a calculation ofutility factor more realistic, based on values ​​read by on-board fuel consumption meters, which will become mandatory for cars sold in the EU in 2021.

This modification, which would have the effect of revising upwards the approved consumption and emissions values ​​of plug-in hybrid cars, would not come into force before 2025.

We imagine that manufacturers would be particularly resistant to such a measure. Indeed, in addition to being misleading for customers, these values ​​give them many tax advantages.

In particular, plug-in hybrid models have a great advantage in the calculations of average CO2 emissions of cars sold by a manufacturer, within the framework of CAFE standards. As a reminder, this regulation aims at European level to impose heavy fines on manufacturers producing cars that emit the most CO2.

Similarly, in France, these models are favored by the bonus-malus system on CO2, but also on weight, since plug-in hybrid cars whose autonomy in town reaches 50 km or more are exempt. The same applies to the tax on company vehicles (TVS), from which cars emitting 50 g of CO2/km or less in the WLTP cycle are exempt.

This tax loophole could take a big hit if homologation values ​​for plug-in hybrid cars become more realistic.

If you are considering the purchase of a plug-in hybrid vehicle, for ecological or economic considerations, know that these cars can still be interesting. Properly used, they effectively reduce fuel consumption and polluting emissions compared to a conventional thermal model. However, they should be recharged as often as possible.

To estimate its consumption, it will therefore be necessary to anticipate its use by estimating the proportion of its journeys that one intends to make in electric mode, taking into account the actual electric autonomy of the models and their recharge time. Similarly, to make its calculations, it will be necessary to base oneself on the discharged battery consumption of the models. Unfortunately, few manufacturers communicate this information – at least this is the case of Ford and Suzuki. You can also consult our car tests, in which we measure the electric range and the actual discharged battery consumption of plug-in hybrid cars, as well as those of our colleagues.