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Plug-in hybrid electric vehicles release almost five times more global warming emissions than lab-reported figures show, as per a recent analysis.

Widening Discrepancy In Official and Real-World Emissions

Data shows that PHEVs emit only 19% less CO₂ than traditional gas and diesel cars, according to analysis conducted by a non-profit group. That differs sharply with lab tests, which assumed a 75% decrease in emissions.

Analysts examined information from in-vehicle energy use monitors of eight hundred thousand vehicles sold in the EU between 2021 and 2023. The team discovered that real-world CO₂ emissions from PHEVs in 2023 were 4.9 times greater than official figures, up from 3.5 times in 2021.

“Actual CO2 output are increasing, while lab-reported figures are decreasing,” stated a senior analyst participating in the study. “That gap is widening and poses a serious issue. Consequently, PHEVs emit almost as heavily as petrol vehicles.”

Primary Factors Behind the Discrepancy

Analysts linked the majority of the difference to overestimates of the “utility factor” – the ratio of kilometers driven in electric mode relative to overall mileage. The team found that only a quarter of driving was done in EV mode, while lab assumptions assumed over four-fifths.

Even, when running in EV mode, emission amounts were well above official estimates. This occurred because EV motors were not strong enough to function alone, leading to combustion motors using gasoline for almost one-third of the distance completed in electric mode.

Regulatory and Economic Implications

Based on calculations, the lowballing of PHEV emissions allowed four major carmaker companies to avoid over €5bn in fines from 2021 and 2023, by artificially simplifying compliance with EU average fleet CO₂ standards.

Furthermore, drivers of PHEVs could spend about €500 more per year in running costs than is estimated under lab tests.

“The strong statements that manufacturers like to make about their PHEV cars are clearly far from the mark,” stated a automotive expert. “Buyers are being misled into thinking that by buying a PHEV, they are benefiting the planet and saving costs. In reality, PHEVs are little better than regular petrol and diesel cars in terms of energy consumption, CO₂ production, and running costs.”

Policy Discussion and Automotive Lobbying

Plug-in hybrid cars have lately been brought back into political debates as carmakers have pressed the European Union to weaken CO₂ standards. A planned ban on sales of new combustion engine cars in 2035 has faced intense pressure from the automotive sector and opposition from EU countries with large car manufacturing.

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

One external energy policy expert, who was not involved with the research, called the analysis a “highly valuable addition” after years in which segments of the car industry claimed there was too little data to accurately evaluate real-world emissions.

“These findings demonstrate, beyond any doubt, that the difference in official and real-world PHEV fuel consumption and CO₂ output is much, much greater than for gasoline or diesel vehicles,” the expert said. “Any regulatory adjustments concerning PHEVs should be implemented with extreme care and in the light of that data.”