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PHEVs release nearly 5x greater planet-heating emissions than official data show, as per a recent analysis.

Growing Discrepancy Between Official and Actual Emissions

Data shows that PHEVs emit just 19% less CO₂ than traditional petrol and diesel cars, according to analysis conducted by a advocacy organization. That contrasts significantly with laboratory tests, which assumed a three-quarters decrease in emissions.

Researchers examined data from in-vehicle energy use meters of 800,000 vehicles sold in Europe from 2021 and 2023. They discovered that real-world CO₂ output from PHEVs in 2023 were 4.9 times higher than lab figures, increased from three and a half times in 2021.

“Actual CO2 output are increasing, while official figures are falling,” said a lead analyst involved in the study. “This discrepancy is growing and creates a serious problem. Consequently, PHEVs emit nearly as much as petrol vehicles.”

Key Reasons Behind the Discrepancy

Researchers attributed most of the gap to overestimates of the “utility factor” – the percentage of miles driven in battery power compared to overall mileage. They found that only a quarter of driving was done in electric mode, while official assumptions assumed over four-fifths.

Additionally, when running in electric mode, pollution levels were significantly higher than lab projections. This occurred because electric motors were insufficiently powerful sufficient to function alone, leading to engines burning fossil fuels for nearly a third of the travel covered in electric mode.

Policy and Financial Implications

Based on calculations, the lowballing of PHEV emissions enabled several large carmaker companies to escape more than €5bn in fines between 2021 and 2023, by falsely simplifying compliance with EU fleet-average CO₂ targets.

Furthermore, drivers of PHEVs could spend approximately €500 extra per year in running expenses than would be estimated under laboratory conditions.

“The bold statements that automakers like to make about their plug-in hybrid cars are obviously far from the mark,” commented a automotive analyst. “Consumers are being duped into believing that by buying a PHEV, they are benefiting the planet and saving costs. Actually, PHEVs are little improved than standard gas and diesel vehicles in terms of energy consumption, CO₂ production, and running costs.”

Policy Discussion and Automotive Lobbying

Hybrid vehicles have lately been drawn back into policy discussions as automakers have lobbied the European Union to relax CO₂ standards. A proposed ban on sales of new internal combustion vehicles in 2035 has faced intense lobbying from the automotive industry and resistance from EU countries with large car manufacturing.

Some high-level politicians have proposed plug-in hybrids as a potential “flexibility” solution to include in the regulation.

One independent energy economics specialist, who was not involved with the research, described the report a “very useful addition” after years in which parts of the automotive industry claimed there was too little data to accurately evaluate real-world emissions.

“The results show, without question, that the difference between official and actual PHEV fuel consumption and CO₂ output is much, much greater than for gasoline or diesel vehicles,” the expert stated. “Any regulatory adjustments concerning PHEVs should be implemented with extreme caution and in the light of this evidence.”