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PHEVs produce nearly five times more planet-heating pollution than lab-reported data show, as per a recent analysis.

Widening Discrepancy In Lab and Real-World CO2 Output

Statistics shows that PHEVs release just one-fifth lower CO₂ than conventional gas and diesel vehicles, according to analysis carried out by a advocacy group. This differs sharply with laboratory estimates, which suggested a 75% decrease in pollution.

Analysts studied information from in-vehicle energy use monitors of 800,000 cars registered in the EU between 2021 and 2023. They found that actual CO₂ output from PHEVs in 2023 were 4.9 times higher than official figures, up from three and a half times in 2021.

“Real-world emissions are increasing, while lab-reported figures are decreasing,” stated a senior researcher participating in the report. “That gap is widening and poses a significant problem. Consequently, PHEVs pollute almost as much as petrol cars.”

Primary Factors Behind the Emissions Gap

Analysts linked most of the difference to overestimates of the “utility factor” – the percentage of miles driven in battery power relative to total mileage. The team found that just a quarter of travel was completed in electric mode, whereas lab assumptions suggested over four-fifths.

Even, when running in electric mode, emission amounts were well above lab estimates. This occurred because electric motors were insufficiently powerful enough to operate alone, resulting to combustion motors burning fossil fuels for almost one-third of the travel covered in electric mode.

Regulatory and Financial Consequences

Based on estimates, the underestimation of PHEV emissions allowed four major carmaker groups to avoid more than €5bn in fines from 2021 and 2023, by falsely easing compliance with European Union average fleet CO₂ targets.

Additionally, owners of PHEVs could spend about €500 more per year in operating costs than is estimated under laboratory conditions.

“The strong statements that automakers often promote about their PHEV cars are obviously way off the truth,” stated a transport analyst. “Consumers are being misled into believing that by buying a PHEV, they are benefiting the planet and saving costs. In reality, PHEVs are only slightly improved than standard gas and diesel cars in terms of energy consumption, CO₂ emissions, and operating expenses.”

Political Debate and Automotive Lobbying

Hybrid cars have recently been drawn again into policy debates as carmakers have lobbied the European Union to weaken CO₂ targets. A planned ban on sales of new internal combustion cars in 2035 has faced heavy lobbying from the automotive sector and opposition from member states with large car manufacturing.

Several high-level officials have proposed PHEVs as a potential “flexibility” option to include in the legislation.

An external energy economics specialist, who was unaffiliated with the study, called the report a “highly valuable addition” after a long period in which segments of the automotive sector argued there was too little data to accurately evaluate real-world emissions.

“These findings demonstrate, without question, that the gap in lab and real-world PHEV energy use and CO₂ emissions is much, much greater than for petrol or diesel vehicles,” the expert said. “Any policy adjustments regarding PHEVs should be implemented with utmost caution and in the light of this evidence.”