Press Release

Plug-in hybrids now emit five times, on average, what official tests claim – EU data

September 10, 2025

But the car lobby is demanding that the EU scrap rules that would better reflect PHEV pollution.

Carbon dioxide emissions from plug-in hybrid (PHEV) cars are almost five times higher, on average, than official tests suggest, according to new data published by the EU. The gap between PHEVs’ CO2 pollution in the real world and tests continues to grow despite carmakers’ claims that the technology has become cleaner. Earlier this month the European carmakers lobby demanded the EU cancel its efforts to better reflect hybrid emissions when calculating their progress towards climate targets.

PHEVs switch between an electric motor using a battery, which is recharged by being plugged in, and a petrol or diesel engine. They account for 8.6% of EU car sales this year and carmakers want to continue selling them even after the 2035 deadline for zero-emission cars. But analysis by T&E of data from the European Environment Agency finds they emit an average of 139g of CO2 per km. That compares with the 28g per km in official tests.

The real-world data was gathered from fuel monitors on 127,000 plug-in hybrid vehicles registered in 2023. It differs hugely from the tests where vehicles are driven in a way that is considered to be normal. The EU has set ‘utility factors’ to correct the CO2 rating. The utility factors set for 2025 and 2027 gradually tighten the gap, meaning carmakers would have to reduce their sales of PHEVs or increase their battery electric car sales in order to comply with EU CO2 targets.

Lucien Mathieu, cars director at T&E, said: “Plug-in hybrids are still worse for the climate than carmakers claim and the gap with reality has only gotten worse. The car industry is demanding that the EU turn a blind eye so it can delay investing in fully electric cars. The EU Commission must stand its ground and stick to the already agreed utility factors for 2025 and 2027.”

PHEVs are expected to be on the agenda when EU Commission president Ursula von der Leyen hosts a ‘strategic dialogue’ with the car industry, T&E and other stakeholders this Friday, 12 September.

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