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PHEVs emit almost five times greater planet-heating emissions than official figures show, as per a recent report.

Widening Discrepancy Between Lab and Real-World CO2 Output

Statistics shows that PHEVs emit only one-fifth lower CO₂ than traditional gas and diesel cars, based on research conducted by a non-profit group. That contrasts significantly with lab tests, which suggested a three-quarters decrease in emissions.

Analysts studied information from onboard fuel consumption monitors of eight hundred thousand vehicles registered in Europe between 2021 and 2023. They found that actual CO₂ emissions from PHEVs in 2023 were 4.9 times higher than lab figures, increased from 3.5 times in 2021.

“Actual CO2 output are increasing, while official emissions are falling,” said a senior researcher involved in the study. “This gap is widening and poses a serious issue. Consequently, PHEVs emit nearly as heavily as gasoline vehicles.”

Key Factors Driving the Emissions Gap

Researchers attributed most of the gap to inflated estimates of the “utility factor” – the percentage of miles driven in electric power compared to overall distance. The team determined that only 27% of travel was done in EV mode, whereas lab estimates assumed 84%.

Even, when running in EV mode, emission amounts were well above official projections. This happened because electric motors were not strong sufficient to operate alone, leading to engines using gasoline for almost one-third of the travel covered in EV mode.

Regulatory and Financial Implications

According to estimates, the lowballing of PHEV CO2 output allowed several large automaker groups to avoid over €5bn in penalties from 2021 and 2023, by artificially simplifying compliance with EU average fleet CO₂ standards.

Additionally, drivers of PHEVs could spend approximately €500 more per year in running costs than is estimated under laboratory tests.

“The strong claims that manufacturers often promote about their PHEV vehicles are obviously far from the mark,” stated a automotive analyst. “Consumers are being misled into thinking that by purchasing a PHEV, they are helping the environment and cutting costs. In reality, PHEVs are little improved than standard petrol and diesel vehicles in terms of fuel use, CO₂ production, and running costs.”

Policy Debate and Industry Pressure

Plug-in hybrid vehicles have lately been brought back into political debates as automakers have pressed the EU to weaken CO₂ targets. A planned ban on new internal combustion vehicles in 2035 has faced intense pressure from the car industry and resistance from member states with significant car industries.

Several senior politicians have proposed plug-in hybrids as a potential “compromise” solution to introduce in the regulation.

One external energy policy expert, who was not involved with the research, called the report a “very useful addition” after years in which parts of the automotive industry claimed there was insufficient data to accurately assess actual emissions.

“The results show, beyond any doubt, that the gap between official and real-world PHEV fuel consumption and CO₂ emissions is much, much larger than for gasoline or conventional vehicles,” they said. “All policy adjustments concerning PHEVs should be implemented with utmost care and in the light of this data.”