Plug-in hybrids emit almost as much CO₂ as petrol cars — new study shakes the green claim

A European study reveals that PHEVs emit nearly five times more CO₂ in real-world driving than manufacturers claim.

For years, plug-in hybrid vehicles (PHEVs) have been promoted as the perfect bridge toward full electrification. However, a recent Transport & Environment report analysing 800,000 cars registered across Europe exposes a very different reality: these models emit up to five times more greenhouse gases than official laboratory figures suggest. In short, they pollute almost as much as conventional petrol cars, calling into question their supposed eco-friendly image.

A massive gap between lab tests and real life

According to the study, PHEVs in real-world use cut CO₂ emissions by just 19% compared to petrol vehicles — a far cry from the 75% reduction claimed in official tests. The discrepancy stems largely from an overestimation of the so-called “utility factor”, which measures how much distance is covered in electric-only mode. While the official figure assumed 84%, the study found that only 27% of total driving is actually electric.

Even when driven in electric mode, the report found that combustion engines still activate for nearly one-third of the journey, as the electric motors aren’t powerful enough to handle all driving scenarios. Consequently, the environmental benefit of these vehicles is far smaller than expected, while the financial savings for drivers are eroded, with up to €500 extra in annual operating costs compared to laboratory estimates.

Automakers under growing scrutiny

The research also points to leading European carmakers, who allegedly avoided more than €5 billion in fines between 2021 and 2023 thanks to the systematic underreporting of PHEV emissions. Experts such as Patrick Plötz from the Fraunhofer Institute stress that these findings “prove beyond doubt that the gap between official and real-world CO₂ emissions is far larger for PHEVs than for petrol or diesel cars.” As a result, the European Commission is now under pressure to rethink its emissions targets and incentive policies for hybrid models.

Political debate over the combustion engine ban

The controversy comes at a decisive moment for the automotive industry, amid heated debate over the 2035 EU ban on combustion-engine cars. German Chancellor Friedrich Merz recently urged that “there should be no drastic cut-off in 2035,” arguing that plug-in hybrids could serve as a flexible middle ground. However, researchers warn that such exemptions would only delay the transition toward truly sustainable mobility, reinforcing the notion that PHEVs are little more than a green illusion.

Conclusion: the end of the hybrid illusion

What was once hailed as a perfect compromise between efficiency and range has now been debunked. Plug-in hybrids fail to deliver on both environmental and economic promises, with real-world pollution levels dangerously close to those of traditional vehicles. In an era where Formula 1 is already experimenting with synthetic fuels and partial electrification, the automotive industry must commit to genuine innovation rather than relying on green marketing narratives.