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Plug-in hybrid cars produce almost 5x more planet-heating pollution than lab-reported figures show, as per a recent analysis.

Widening Discrepancy In Official and Actual Emissions

Statistics shows that PHEVs release only 19% lower CO₂ than traditional petrol and diesel vehicles, based on research conducted by a non-profit organization. That differs sharply with laboratory tests, which assumed a 75% reduction in pollution.

Analysts studied data from in-vehicle energy use meters of eight hundred thousand cars registered in the EU between 2021 and 2023. They found that actual CO₂ emissions from PHEVs in 2023 were nearly five times higher than lab figures, increased from 3.5 times in 2021.

“Actual emissions are increasing, while lab-reported emissions are falling,” said a lead analyst participating in the study. “That gap is growing and poses a serious issue. Consequently, PHEVs emit nearly as heavily as gasoline cars.”

Key Factors Behind the Emissions Gap

Analysts linked the majority of the difference to inflated estimates of the “electric driving share” – the percentage of kilometers driven in electric mode relative to overall distance. The team found that just a quarter of driving was completed in electric mode, while official estimates assumed over four-fifths.

Additionally, when running in EV mode, pollution amounts were well above official estimates. That occurred because electric motors were not strong enough to operate alone, resulting to combustion motors using fossil fuels for almost a third of the travel completed in EV mode.

Policy and Financial Implications

According to calculations, the underestimation of PHEV CO2 output enabled four major carmaker groups to escape over €5bn in fines between 2021 and 2023, by artificially simplifying adherence with EU average fleet CO₂ targets.

Furthermore, drivers of PHEVs would spend about €500 more annually in running costs than would be assumed under lab tests.

“The strong claims that manufacturers like to make about their PHEV vehicles are clearly way off the mark,” commented a automotive expert. “Buyers are being misled into believing that by purchasing a PHEV, they are benefiting the environment and cutting costs. In reality, PHEVs are little better than regular petrol and diesel cars in terms of fuel consumption, CO₂ emissions, and operating expenses.”

Policy Discussion and Industry Lobbying

Hybrid cars have lately been brought again into policy debates as carmakers have pressed the European Union to relax CO₂ standards. A planned ban on sales of new combustion engine vehicles in 2035 has faced intense lobbying from the automotive sector and resistance from member states with large automotive manufacturing.

Some senior officials have suggested plug-in hybrids as a potential “compromise” solution to introduce in the regulation.

One external energy economics specialist, who was unaffiliated with the study, called the analysis a “very useful contribution” after years in which parts of the car industry claimed there was too little information to accurately assess actual CO2 output.

“The results show, beyond any doubt, that the difference in official and actual PHEV energy use and CO₂ emissions is much, much greater than for gasoline or conventional vehicles,” they stated. “All regulatory adjustments concerning PHEVs should be made with extreme care and considering this data.”