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PHEVs produce nearly 5x greater planet-heating pollution than lab-reported figures show, according to a recent report.

Widening Discrepancy In Official and Actual Emissions

Data shows that PHEVs release only one-fifth lower CO₂ than traditional gas and diesel vehicles, according to analysis conducted by a advocacy group. This contrasts sharply with laboratory tests, which assumed a three-quarters reduction in pollution.

Analysts studied information from onboard energy use monitors of 800,000 vehicles sold in Europe between 2021 and 2023. They found that actual CO₂ emissions from PHEVs in 2023 were 4.9 times greater than official figures, increased from three and a half times in 2021.

“Real-world CO2 output are increasing, while lab-reported figures are falling,” stated a lead researcher involved in the report. “This discrepancy is widening and creates a serious issue. Consequently, PHEVs pollute nearly as heavily as gasoline vehicles.”

Primary Factors Driving the Discrepancy

Analysts attributed the majority of the difference to inflated estimates of the “electric driving share” – the percentage of kilometers driven in battery power compared to total distance. They determined that just 27% of driving was done in electric mode, whereas lab assumptions suggested over four-fifths.

Even, when operating in EV mode, emission levels were well above lab projections. This happened because EV motors were not strong sufficient to operate independently, resulting to engines burning gasoline for almost a third of the distance completed in EV mode.

Policy and Economic Consequences

Based on estimates, the underestimation of PHEV emissions enabled four major automaker groups to escape over €5bn in penalties between 2021 and 2023, by artificially simplifying adherence with European Union average fleet CO₂ standards.

Additionally, drivers of PHEVs would pay approximately €500 more annually in operating expenses than is estimated under laboratory tests.

“The bold statements that manufacturers often promote about their PHEV cars are clearly way off the mark,” commented a transport expert. “Consumers are being misled into believing that by buying a PHEV, they are helping the planet and cutting costs. Actually, PHEVs are only slightly better than standard gas and diesel vehicles in terms of fuel use, CO₂ emissions, and running costs.”

Political Discussion and Automotive Pressure

Hybrid vehicles have recently been drawn again into political discussions as carmakers have pressed the European Union to relax CO₂ targets. A planned prohibition on new combustion engine vehicles in 2035 has faced heavy pressure from the automotive sector and resistance from EU countries with large automotive industries.

Some senior officials have suggested PHEVs as a possible “flexibility” option to include in the regulation.

One independent energy policy expert, who was unaffiliated with the study, called the report a “highly valuable contribution” after years in which parts of the car industry argued there was insufficient data to properly evaluate actual CO2 output.

“These findings show, without question, that the gap in official and real-world PHEV fuel consumption and CO₂ emissions is significantly larger than for gasoline or conventional cars,” the expert stated. “Any regulatory adjustments concerning PHEVs should be implemented with extreme caution and in the light of this evidence.”