A major new study has found that plug-in hybrid electric vehicles (PHEVs) consume on average three times more fuel than manufacturers claim. The analysis, conducted by the Fraunhofer Institute, examined real-world data from around one million PHEVs produced between 2021 and 2023.
While official EU certification figures suggest PHEVs use between one and two litres of fuel per 100 kilometres, the study found actual consumption averages six litres per 100 km. Researchers attributed the discrepancy to the combustion engine being triggered far more frequently than previously assumed, even when the vehicle is in electric mode.
Porsche hybrids performed worst, consuming around seven litres per 100 km, while cheaper models from Kia, Toyota, Ford and Renault often used under one litre per 100 km. Porsche defended its figures, stating they comply with EU measurement procedures and that deviations arise from differing usage patterns and external conditions.
Lead researcher Patrick Plötz urged regulators to use real-world emissions data and consider penalties for manufacturers that fail to meet on-road limits. The EU Commission declined to comment, while the German Association of the Automotive Industry maintained that existing measurement methods are reliable.
