Real-World Fuel Consumption of Plug-In Hybrid Electric Vehicles Exceeds Manufacturer Claims

A recent analysis conducted by the Fraunhofer Institute has found that plug-in hybrid electric vehicles (PHEVs) consume significantly more fuel on the road than manufacturers claim. The study, which is considered the most extensive of its kind, analyzed data from approximately one million PHEVs produced between 2021 and 2023. This data, transmitted wirelessly from the vehicles, allowed researchers to assess real-world fuel consumption, contrasting sharply with the official EU-approved figures provided by manufacturers.

The Guardian

PHEVs, which combine a petrol or diesel engine with a battery-powered electric motor, are marketed as energy-efficient alternatives to conventional vehicles. Manufacturers typically advertise these cars as using between one and two liters of fuel per 100 kilometers. However, the Fraunhofer Institute's findings indicate that, on average, these vehicles actually require six liters per 100 kilometers—an increase of about 300% over the stated figures.

The Guardian

The study attributes the inflated fuel usage primarily to the frequent switching between the electric and combustion engines. Patrick Plötz, a researcher at the Fraunhofer Institute, noted that the combustion engine is activated more often than previously believed. This contradicts manufacturers' claims that PHEVs consume little to no fuel when operating in electric mode. Among the vehicles analyzed, German-manufactured PHEVs, particularly high-end models from Porsche, exhibited the highest fuel consumption rates, with some models consuming around seven liters per 100 kilometers.

The Guardian

In contrast, the analysis revealed that lower-end PHEVs from manufacturers such as Kia, Toyota, Ford, and Renault demonstrated significantly better fuel efficiency, often using less than one liter per 100 kilometers—up to 85% less fuel than the Porsche models. When questioned about the discrepancies in fuel consumption, Porsche attributed the differences to "differing usage patterns," asserting that their measurements comply with legal EU standards designed to ensure uniformity across Europe.

The Guardian

The findings have prompted calls for EU regulators to revise their measurement methodologies to reflect real-world fuel consumption more accurately. Researchers advocate for stricter controls on how PHEV fuel consumption is assessed, emphasizing that current CO2 emission limits for manufacturers' vehicle fleets need urgent reevaluation. The EU Commission, responsible for these limits, declined to comment on the study's findings, while the German Association of the Automotive Industry defended the reliability of existing measures for determining fuel consumption and CO2 emissions.

The Guardian

The Fraunhofer Institute's analysis highlights a significant gap between the advertised and actual fuel consumption of PHEVs, raising concerns about the environmental impact of these vehicles. As the automotive industry faces increasing scrutiny over emissions, the need for transparent and accurate reporting of fuel efficiency has never been more critical.

The Guardian