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PHEVs produce nearly five times more global warming pollution than official data indicate, according to a recent analysis.

Widening Gap Between Lab and Actual Emissions

Data shows that PHEVs release only one-fifth lower CO₂ than conventional gas and diesel vehicles, according to analysis conducted by a advocacy organization. That contrasts significantly with laboratory tests, which assumed a three-quarters decrease in emissions.

Researchers examined information from in-vehicle fuel consumption meters of 800,000 vehicles sold in Europe between 2021 and 2023. The team found that actual CO₂ emissions from PHEVs in 2023 were 4.9 times greater than lab estimates, increased from three and a half times in 2021.

“Real-world CO2 output are rising, while official emissions are decreasing,” said a senior researcher participating in the study. “That gap is widening and creates a serious issue. Consequently, PHEVs pollute almost as much as gasoline vehicles.”

Primary Reasons Behind the Emissions Gap

Analysts attributed the majority of the difference to overestimates of the “utility factor” – the percentage of kilometers travelled in electric mode compared to overall mileage. They found that just 27% of driving was done in EV mode, whereas lab estimates suggested 84%.

Even, when operating in electric mode, emission amounts were significantly higher than official projections. That happened because EV motors were not strong enough to operate independently, leading to combustion motors using fossil fuels for nearly a third of the travel covered in electric mode.

Regulatory and Economic Consequences

According to estimates, the underestimation of PHEV CO2 output enabled four large automaker companies to escape over €5bn in penalties between 2021 and 2023, by falsely simplifying adherence with European Union fleet-average CO₂ standards.

Additionally, drivers of PHEVs would pay about €500 more per year in operating costs than would be assumed under lab conditions.

“The bold statements that manufacturers like to make about their PHEV vehicles are clearly far from the truth,” commented a automotive expert. “Buyers are being duped into thinking that by buying a PHEV, they are benefiting the planet and cutting money. Actually, PHEVs are little better than regular petrol and diesel vehicles in terms of fuel consumption, CO₂ production, and running costs.”

Political Debate and Automotive Pressure

Hybrid cars have lately been brought back into policy discussions as automakers have lobbied the European Union to weaken CO₂ targets. A proposed ban on sales of new internal combustion cars in 2035 has faced heavy lobbying from the car sector and resistance from member states with significant automotive industries.

Some high-level officials have suggested plug-in hybrids as a possible “flexibility” option to introduce in the legislation.

An independent energy policy expert, who was unaffiliated with the study, described the analysis a “highly valuable contribution” after a long period in which segments of the car sector claimed there was too little data to properly evaluate actual CO2 output.

“The results show, without question, that the gap in lab and real-world PHEV fuel consumption and CO₂ emissions is significantly greater than for petrol or diesel vehicles,” the expert stated. “Any regulatory adjustments concerning PHEVs should be implemented with extreme care and considering this evidence.”