Hybrid vehicles emit significantly more carbon dioxide in real-world driving than official European Union figures indicate and should not be considered low-emission vehicles, according to a report published on Wednesday by transport research and campaign group Transport & Environment (T&E).
The report, citing data from the European Environmental Agency, found that plug-in hybrid (PHEV) models produce over 130 grams of CO2 per kilometre on average, comparable to a conventional mid-size petrol car and nearly five times higher than official test figures of under 30 grams per kilometre.
“Plug-in hybrids are being marketed as low-emission vehicles, but actually if you compare them to petrol cars in real-world performance, they’re very, very similar,” said T&E Executive Director William Todts.
The discrepancy largely stems from overly optimistic assumptions about the share of driving powered solely by electricity, known as the utility factor. T&E noted that planned revisions to the EU methodology in 2025-2026 and 2027-2028 will narrow the gap, though real-world emissions are expected to remain about 18% above official figures.
The report also urges automakers to increase hybrid battery capacity to ensure vehicles operate more frequently on electric power. In 2024, plug-in and other hybrid vehicles accounted for 38% of new vehicle sales in the EU, while fully electric vehicles represented 13.6% of the market, according to the European Automobile Manufacturers Association (ACEA).
European auto executives are expected to discuss the EU’s CO2 targets and the future of the sector with European Commission President Ursula von der Leyen on Friday, amid concerns that stricter regulations could affect hybrid sales.