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PHEVs produce almost 5x more planet-heating pollution than lab-reported figures show, as per a new analysis.

Growing Discrepancy Between Official and Actual CO2 Output

Statistics reveals that PHEVs release just 19% less CO₂ than conventional petrol and diesel vehicles, according to research conducted by a advocacy organization. That contrasts sharply with laboratory estimates, which assumed a three-quarters reduction in emissions.

Analysts studied information from in-vehicle energy use monitors of 800,000 cars registered in Europe between 2021 and 2023. The team found that actual CO₂ emissions from PHEVs in 2023 were 4.9 times greater than official estimates, increased from three and a half times in 2021.

“Real-world CO2 output are increasing, while lab-reported emissions are decreasing,” said a lead analyst participating in the study. “This discrepancy is widening and poses a significant issue. As a result, PHEVs emit almost as heavily as gasoline cars.”

Primary Reasons Behind the Emissions Gap

Researchers attributed the majority of the difference to inflated estimates of the “electric driving share” – the percentage of miles travelled in battery mode relative to total distance. The team determined that only a quarter of travel was done in EV mode, while official assumptions assumed 84%.

Additionally, when operating in EV mode, pollution amounts were well above lab estimates. That happened because EV motors were not strong sufficient to function alone, resulting to combustion motors using gasoline for nearly one-third of the distance completed in electric mode.

Regulatory and Economic Consequences

Based on estimates, the lowballing of PHEV emissions allowed four large automaker companies to escape more than €5bn in penalties between 2021 and 2023, by falsely simplifying adherence with EU fleet-average CO₂ targets.

Additionally, drivers of PHEVs could spend about €500 more annually in operating expenses than would be estimated under laboratory conditions.

“The strong claims that automakers often promote about their plug-in hybrid cars are obviously way off the truth,” commented a automotive expert. “Buyers are being duped into believing that by buying a PHEV, they are helping the environment and cutting costs. In reality, PHEVs are little better than regular petrol and diesel cars in terms of fuel consumption, CO₂ production, and operating costs.”

Political Discussion and Automotive Lobbying

Plug-in hybrid cars have recently been brought again into political discussions as automakers have lobbied the EU to weaken CO₂ targets. A proposed prohibition on new combustion engine cars in 2035 has faced heavy lobbying from the automotive sector and resistance from EU countries with large automotive industries.

Some high-level politicians have suggested PHEVs as a possible “flexibility” solution to include in the legislation.

One independent energy policy specialist, who was not involved with the research, called the analysis a “highly valuable contribution” after years in which segments of the automotive sector argued there was too little data to accurately assess real-world emissions.

“These findings demonstrate, without question, that the gap in official and actual PHEV fuel consumption and CO₂ emissions is significantly greater than for petrol or conventional vehicles,” the expert said. “Any policy adjustments concerning PHEVs should be implemented with utmost care and considering that evidence.”