🔗 Share this article

Plug-in hybrid cars produce almost five times greater global warming pollution than official figures indicate, according to a recent report.

Widening Gap Between Official and Real-World Emissions

Statistics shows that PHEVs release just 19% less CO₂ than conventional gas and diesel vehicles, according to research carried out by a non-profit group. That contrasts sharply with laboratory tests, which suggested a three-quarters reduction in emissions.

Analysts examined data from onboard energy use meters of eight hundred thousand vehicles registered in Europe between 2021 and 2023. The team found that actual CO₂ output from PHEVs in 2023 were 4.9 times higher than official estimates, increased from three and a half times in 2021.

“Actual CO2 output are increasing, while lab-reported emissions are falling,” said a lead researcher participating in the study. “This discrepancy is widening and creates a significant issue. Consequently, PHEVs pollute almost as much as gasoline cars.”

Key Reasons Driving the Emissions Gap

Researchers attributed the majority of the gap to inflated estimates of the “utility factor” – the percentage of kilometers driven in battery power relative to overall distance. The team determined that just 27% of driving was completed in EV mode, whereas official estimates suggested over four-fifths.

Even, when operating in EV mode, emission levels were well above official estimates. This happened because electric motors were not strong enough to operate alone, leading to engines using fossil fuels for nearly one-third of the travel completed in electric mode.

Regulatory and Economic Consequences

Based on calculations, the lowballing of PHEV CO2 output enabled four large automaker companies to escape over €5bn in penalties from 2021 and 2023, by falsely simplifying compliance with European Union fleet-average CO₂ targets.

Furthermore, drivers of PHEVs would pay approximately €500 more per year in running expenses than is assumed under laboratory conditions.

“The bold claims that manufacturers like to make about their plug-in hybrid cars are clearly way off the mark,” stated a transport analyst. “Consumers are being misled into believing that by purchasing a PHEV, they are helping the environment and saving costs. Actually, PHEVs are little improved than regular petrol and diesel cars in terms of fuel consumption, CO₂ emissions, and running costs.”

Policy Debate and Automotive Pressure

Hybrid cars have lately been brought back into political debates as carmakers have pressed the EU to relax CO₂ targets. A proposed ban on sales of new internal combustion cars in 2035 has faced heavy lobbying from the car industry and resistance from member states with large automotive industries.

Some senior officials have proposed PHEVs as a potential “compromise” solution to introduce in the legislation.

An independent energy economics specialist, who was not involved with the research, described the report a “very useful contribution” after a long period in which parts of the car industry argued there was insufficient information to accurately evaluate real-world emissions.

“The results show, without question, that the gap between official and real-world PHEV energy use and CO₂ emissions is significantly greater than for gasoline or conventional vehicles,” they stated. “All regulatory adjustments concerning PHEVs should be implemented with extreme caution and considering that data.”