Plug-in Hybrid Cars Emit Almost as Heavily as Gasoline Vehicles, Report Finds
Plug-in hybrid electric vehicles release almost 5x more planet-heating pollution than lab-reported data show, according to a recent analysis.
Growing Gap Between Official and Actual CO2 Output
Statistics reveals that PHEVs emit just 19% less CO2 than traditional petrol and diesel cars, based on research conducted by a non-profit group. That differs significantly with lab tests, which assumed a 75% decrease in pollution.
Researchers examined information from onboard energy use monitors of 800,000 vehicles registered in Europe between 2021 and 2023. They found that real-world CO2 output from PHEVs in 2023 were 4.9 times greater than lab figures, increased from three and a half times in 2021.
“Actual CO2 output are increasing, while official emissions are falling,” said a lead researcher involved in the report. “This gap is growing and poses a significant issue. Consequently, PHEVs pollute nearly as heavily as gasoline cars.”
Key Factors Driving the Discrepancy
Analysts attributed the majority of the difference to overestimates of the “utility factor” – the ratio of miles driven in battery power compared to total mileage. They determined that only a quarter of travel was done in electric mode, while lab estimates assumed over four-fifths.
Additionally, when operating in electric mode, emission amounts were well above official projections. This happened because electric motors were not strong sufficient to operate alone, resulting to combustion motors burning fossil fuels for almost a third of the travel completed in electric mode.
Policy and Financial Consequences
According to estimates, the lowballing of PHEV emissions allowed several large automaker groups to avoid over €5bn in penalties between 2021 and 2023, by falsely easing adherence with EU fleet-average CO2 standards.
Additionally, owners of PHEVs would pay approximately €500 more per year in running costs than is estimated under laboratory conditions.
“The strong statements that automakers often promote about their plug-in hybrid cars are clearly way off the mark,” stated a transport expert. “Buyers are being duped into believing that by buying a PHEV, they are benefiting the planet and saving costs. Actually, PHEVs are only slightly better than regular petrol and diesel cars in terms of energy consumption, CO2 emissions, and operating expenses.”
Political Debate and Automotive Lobbying
Hybrid cars have recently been drawn back into policy discussions as carmakers have lobbied the European Union to relax CO2 targets. A planned ban on new internal combustion vehicles in 2035 has faced heavy pressure from the car sector and opposition from EU countries with significant automotive industries.
Several high-level officials have proposed PHEVs as a potential “flexibility” solution to include in the regulation.
An external energy economics specialist, who was not involved with the study, described the report a “very useful contribution” after years in which segments of the car industry claimed there was too little information to properly evaluate real-world emissions.
“These findings demonstrate, without question, that the gap in official and real-world PHEV fuel consumption and CO2 output is significantly larger than for petrol or diesel vehicles,” they said. “All policy changes regarding PHEVs should be made with extreme care and considering that evidence.”
