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PHEVs emit almost five times more global warming emissions than lab-reported figures show, as per a new report.

Growing Gap Between Lab and Actual CO2 Output

Statistics shows that PHEVs emit just 19% less CO₂ than traditional gas and diesel cars, based on analysis conducted by a non-profit organization. That differs sharply with lab estimates, which suggested a three-quarters decrease in pollution.

Researchers examined data from in-vehicle fuel consumption meters of eight hundred thousand cars registered in Europe between 2021 and 2023. They found that real-world CO₂ output from PHEVs in 2023 were nearly five times greater than official figures, increased from 3.5 times in 2021.

“Real-world CO2 output are increasing, while lab-reported emissions are decreasing,” said a senior researcher participating in the study. “That gap is growing and poses a serious issue. Consequently, PHEVs emit almost as heavily as gasoline vehicles.”

Primary Reasons Driving the Discrepancy

Analysts linked most of the gap to inflated estimates of the “utility factor” – the percentage of kilometers travelled in battery power relative to total distance. The team determined that just 27% of driving was completed in electric mode, while official assumptions suggested 84%.

Even, when operating in EV mode, pollution amounts were well above lab projections. That happened because electric motors were not strong enough to function independently, resulting to combustion motors burning fossil fuels for nearly a third of the distance covered in electric mode.

Policy and Economic Implications

According to calculations, the underestimation of PHEV emissions enabled four large automaker companies to escape more than €5bn in fines from 2021 and 2023, by falsely easing compliance with European Union fleet-average CO₂ targets.

Furthermore, drivers of PHEVs would spend approximately €500 more per year in running costs than is estimated under lab tests.

“The strong statements that automakers often promote about their PHEV cars are clearly way off the truth,” commented a automotive expert. “Buyers are being duped into believing that by buying a PHEV, they are helping the planet and saving costs. Actually, PHEVs are little improved than regular petrol and diesel vehicles in terms of energy use, CO₂ production, and operating costs.”

Political Debate and Automotive Pressure

Hybrid vehicles have recently been brought back into political debates as carmakers have pressed the EU to relax CO₂ targets. A planned prohibition on new internal combustion vehicles in 2035 has faced heavy lobbying from the automotive industry and opposition from EU countries with large car manufacturing.

Some senior officials have suggested PHEVs as a possible “compromise” solution to introduce in the regulation.

One external energy policy specialist, who was not involved with the research, described the report a “highly valuable contribution” after years in which segments of the automotive industry argued there was too little information to accurately evaluate real-world emissions.

“These findings demonstrate, beyond any doubt, that the difference between official and real-world PHEV fuel consumption and CO₂ emissions is much, much greater than for gasoline or diesel vehicles,” the expert said. “Any policy changes concerning PHEVs should be implemented with utmost care and in the light of that evidence.”