Plug in Hybrid Vehicles Pollute Nearly as Much as Gasoline Cars, Study Finds

Plug-in hybrid electric vehicles produce nearly 5x more planet-heating emissions than lab-reported figures indicate, as per a recent analysis.

Widening Gap In Lab and Real-World Emissions

Statistics reveals that PHEVs release only one-fifth lower CO₂ than traditional gas and diesel cars, based on analysis carried out by a non-profit group. That differs significantly with lab estimates, which suggested a three-quarters decrease in pollution.

Researchers studied information from onboard fuel consumption monitors of 800,000 vehicles sold in the EU between 2021 and 2023. They discovered that real-world CO₂ output from PHEVs in 2023 were nearly five times higher than official estimates, increased from three and a half times in 2021.

“Real-world CO2 output are increasing, while lab-reported emissions are falling,” stated a lead researcher involved in the study. “This gap is widening and poses a significant problem. Consequently, PHEVs emit nearly as heavily as petrol cars.”

Key Reasons Behind the Discrepancy

Analysts attributed most of the gap to inflated estimates of the “utility factor” – the ratio of miles driven in battery power compared to overall distance. They found that only 27% of driving was completed in electric mode, whereas lab estimates suggested over four-fifths.

Even, when operating in EV mode, emission amounts were well above official estimates. That happened because electric motors were insufficiently powerful enough to function independently, leading to engines burning fossil fuels for almost one-third of the travel completed in electric mode.

Policy and Economic Implications

According to estimates, the lowballing of PHEV CO2 output enabled several major carmaker groups to escape over €5bn in penalties from 2021 and 2023, by artificially easing compliance with EU fleet-average CO₂ targets.

Furthermore, owners of PHEVs could pay about €500 extra per year in operating costs than is assumed under lab tests.

“The strong claims that automakers often promote about their plug-in hybrid vehicles are obviously far from the truth,” stated a transport expert. “Buyers are being duped into thinking that by buying a PHEV, they are helping the planet and saving money. In reality, PHEVs are only slightly improved than standard petrol and diesel vehicles in terms of fuel use, CO₂ production, and running expenses.”

Political Discussion and Industry Pressure

Plug-in hybrid cars have recently been drawn back into political debates as carmakers have lobbied the EU to relax CO₂ targets. A proposed ban on sales of new internal combustion cars in 2035 has faced intense lobbying from the automotive sector and resistance from member states with significant automotive manufacturing.

Some senior officials have suggested plug-in hybrids as a potential “compromise” solution to include in the regulation.

One external energy economics specialist, who was not involved with the research, called the report a “very useful addition” after a long period in which segments of the car industry claimed there was insufficient data to accurately assess real-world emissions.

“The results demonstrate, without question, that the difference in official and real-world PHEV fuel consumption and CO₂ emissions is much, much larger than for petrol or diesel vehicles,” they said. “Any policy adjustments regarding PHEVs should be implemented with extreme caution and considering this evidence.”