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Plug-in hybrid electric vehicles emit nearly 5x more planet-heating pollution than lab-reported figures show, as per a recent analysis.

Growing Gap In Official and Actual CO2 Output

Data shows that PHEVs release just 19% less CO₂ than traditional petrol and diesel vehicles, based on research carried out by a advocacy organization. This differs significantly with laboratory estimates, which assumed a three-quarters reduction in emissions.

Analysts studied information from onboard energy use meters of eight hundred thousand cars registered in Europe between 2021 and 2023. They found that real-world CO₂ emissions from PHEVs in 2023 were nearly five times higher than official estimates, up from 3.5 times in 2021.

“Actual emissions are increasing, while lab-reported figures are decreasing,” said a senior analyst involved in the study. “This discrepancy is widening and creates a serious problem. Consequently, PHEVs pollute nearly as heavily as petrol cars.”

Primary Reasons Driving the Emissions Gap

Analysts linked most of the difference to inflated estimates of the “electric driving share” – the percentage of kilometers driven in battery mode relative to total distance. The team determined that only a quarter of driving was done in electric mode, while lab assumptions suggested over four-fifths.

Even, when running in EV mode, emission amounts were significantly higher than official estimates. This happened because electric motors were insufficiently powerful enough to function independently, leading to combustion motors using gasoline for nearly a third of the travel completed in EV mode.

Policy and Economic Consequences

According to calculations, the lowballing of PHEV CO2 output enabled several large carmaker companies to escape over €5bn in fines between 2021 and 2023, by falsely easing adherence with European Union average fleet CO₂ standards.

Furthermore, drivers of PHEVs would spend approximately €500 extra annually in operating costs than is estimated under lab tests.

“The strong claims that automakers often promote about their PHEV cars are obviously far from the mark,” stated a transport expert. “Buyers are being misled into believing that by buying a PHEV, they are benefiting the environment and cutting money. Actually, PHEVs are little better than regular gas and diesel vehicles in terms of fuel use, CO₂ production, and running costs.”

Political Debate and Automotive Lobbying

Plug-in hybrid vehicles have lately been brought back into policy discussions as automakers have pressed the EU to weaken CO₂ standards. A planned ban on new internal combustion cars in 2035 has faced heavy lobbying from the car industry and resistance from EU countries with large car manufacturing.

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

An independent energy policy expert, who was not involved with the research, called the report a “very useful addition” after years in which parts of the automotive sector argued there was too little data to accurately assess actual emissions.

“These findings show, without question, that the gap between official and actual PHEV fuel consumption and CO₂ output is significantly larger than for petrol or conventional cars,” they stated. “All policy adjustments concerning PHEVs should be made with utmost care and considering that evidence.”