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Plug-in hybrid cars emit almost five times greater global warming pollution than lab-reported data show, as per a recent analysis.

Growing Discrepancy In Lab and Real-World CO2 Output

Statistics reveals that PHEVs emit just one-fifth less CO₂ than traditional gas and diesel vehicles, according to analysis conducted by a non-profit group. That contrasts significantly with lab tests, which assumed a 75% reduction in pollution.

Analysts studied data from in-vehicle energy use monitors of eight hundred thousand cars sold in Europe between 2021 and 2023. They discovered that real-world CO₂ emissions from PHEVs in 2023 were nearly five times greater than lab estimates, increased from 3.5 times in 2021.

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

Primary Factors Driving the Discrepancy

Researchers attributed the majority of the difference to inflated estimates of the “electric driving share” – the percentage of miles travelled in battery mode compared to overall distance. They found that just 27% of travel was done in EV mode, while official estimates suggested 84%.

Additionally, when operating in electric mode, emission amounts were significantly higher than lab projections. That occurred because EV motors were insufficiently powerful sufficient to operate independently, leading to combustion motors burning fossil fuels for almost one-third of the travel completed in electric mode.

Regulatory and Financial Consequences

Based on calculations, the underestimation of PHEV CO2 output allowed several major carmaker groups to escape over €5bn in fines between 2021 and 2023, by falsely simplifying compliance with European Union fleet-average CO₂ standards.

Additionally, drivers of PHEVs could pay about €500 extra per year in operating expenses than would be assumed under laboratory tests.

“The bold statements that automakers like to make about their PHEV vehicles are clearly way off the mark,” stated a automotive analyst. “Consumers are being misled into believing that by buying a PHEV, they are benefiting the environment and saving costs. In reality, PHEVs are only slightly better than standard gas and diesel vehicles in terms of energy consumption, CO₂ production, and operating costs.”

Policy Discussion and Automotive Pressure

Plug-in hybrid vehicles have lately been brought back into political debates as automakers have pressed the EU to relax CO₂ targets. A planned prohibition on sales of new internal combustion vehicles in 2035 has faced intense pressure from the automotive sector and opposition from member states with large automotive industries.

Some senior politicians have suggested plug-in hybrids as a possible “flexibility” option to introduce in the regulation.

An independent energy economics specialist, who was not involved with the study, described the analysis a “very useful addition” after a long period in which parts of the car industry claimed there was insufficient information to properly evaluate actual CO2 output.

“These findings show, beyond any doubt, that the gap between official and actual PHEV fuel consumption and CO₂ output is significantly larger than for petrol or diesel vehicles,” the expert said. “Any policy changes regarding PHEVs should be implemented with utmost care and in the light of that evidence.”