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Plug-in hybrid cars emit almost 5x more planet-heating emissions than official data show, as per a recent report.

Widening Discrepancy Between Official and Real-World Emissions

Statistics shows that PHEVs emit just 19% lower CO₂ than traditional petrol and diesel cars, based on research carried out by a non-profit group. This contrasts sharply with laboratory estimates, which suggested a three-quarters decrease in emissions.

Analysts studied data from onboard energy use meters of eight hundred thousand cars registered in the EU from 2021 and 2023. They found that real-world CO₂ emissions from PHEVs in 2023 were 4.9 times greater than lab figures, up from 3.5 times in 2021.

“Actual emissions are rising, while lab-reported emissions are falling,” said a senior researcher involved in the study. “That gap is widening and creates a significant problem. Consequently, PHEVs pollute nearly as much as gasoline vehicles.”

Primary Reasons Driving the Discrepancy

Analysts attributed the majority of the difference to inflated estimates of the “electric driving share” – the percentage of miles driven in battery mode relative to overall mileage. They found that just a quarter of travel was done in EV mode, while lab assumptions suggested 84%.

Even, when running in electric mode, emission amounts were significantly higher than lab projections. That happened because electric motors were not strong enough to function independently, resulting to combustion motors burning fossil fuels for nearly a third of the travel completed in EV mode.

Regulatory and Financial Implications

Based on calculations, the lowballing of PHEV emissions enabled four major carmaker groups to escape more than €5bn in penalties between 2021 and 2023, by falsely simplifying compliance with European Union average fleet CO₂ standards.

Additionally, owners of PHEVs could spend approximately €500 extra per year in operating expenses than is assumed under lab conditions.

“The strong claims that manufacturers often promote about their plug-in hybrid cars are clearly far from the mark,” stated a automotive analyst. “Buyers are being duped into thinking that by buying a PHEV, they are benefiting the environment and saving money. Actually, PHEVs are little improved than regular gas and diesel cars in terms of fuel use, CO₂ production, and operating expenses.”

Policy Debate and Industry Pressure

Hybrid vehicles have lately been brought back into policy debates as carmakers have pressed the EU to relax CO₂ standards. A planned prohibition on sales of new internal combustion cars in 2035 has faced heavy lobbying from the automotive industry and resistance from EU countries with large car industries.

Several high-level officials have suggested PHEVs as a possible “compromise” solution to include in the legislation.

One independent energy policy specialist, who was unaffiliated with the research, called the analysis a “very useful addition” after a long period in which parts of the car industry claimed there was too little data to accurately assess actual emissions.

“These findings demonstrate, without question, that the difference in lab and real-world PHEV fuel consumption and CO₂ emissions is significantly greater than for petrol or diesel vehicles,” the expert stated. “Any policy changes concerning PHEVs should be made with extreme caution and in the light of that evidence.”