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PHEVs emit nearly five times more global warming pollution than official figures show, as per a new analysis.

Widening Discrepancy Between Official and Actual Emissions

Statistics shows that PHEVs release just one-fifth less CO₂ than conventional petrol and diesel vehicles, based on analysis carried out by a advocacy organization. This contrasts significantly with laboratory estimates, which suggested a three-quarters decrease in pollution.

Researchers examined data from in-vehicle fuel consumption meters of 800,000 vehicles sold in the EU between 2021 and 2023. The team found that real-world CO₂ emissions from PHEVs in 2023 were nearly five times higher than lab figures, increased from three and a half times in 2021.

“Actual emissions are increasing, while official emissions are falling,” said a senior researcher involved in the study. “This discrepancy is growing and poses a serious problem. Consequently, PHEVs pollute almost as heavily as petrol vehicles.”

Primary Reasons Driving the Emissions Gap

Researchers attributed most of the difference to overestimates of the “utility factor” – the ratio of miles travelled in battery power relative to overall mileage. The team determined that only 27% of driving was done in EV mode, while official estimates suggested over four-fifths.

Additionally, when running in electric mode, emission levels were significantly higher than lab estimates. That occurred because electric motors were insufficiently powerful sufficient to function independently, resulting to engines burning fossil fuels for almost a third of the travel completed in EV mode.

Policy and Financial Implications

Based on calculations, the underestimation of PHEV CO2 output allowed several large automaker companies to avoid over €5bn in penalties between 2021 and 2023, by artificially simplifying adherence with European Union average fleet CO₂ standards.

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

“The strong statements that manufacturers often promote about their plug-in hybrid vehicles are obviously way off the truth,” stated a automotive analyst. “Buyers are being misled into believing that by purchasing a PHEV, they are benefiting the environment and cutting costs. In reality, PHEVs are only slightly improved than regular petrol and diesel vehicles in terms of energy use, CO₂ production, and operating expenses.”

Political Debate and Industry Lobbying

Plug-in hybrid vehicles have lately been drawn again into political debates as carmakers have pressed the European Union to relax CO₂ targets. A proposed ban on new internal combustion cars in 2035 has faced intense lobbying from the car industry and opposition from member states with significant automotive manufacturing.

Some senior politicians have proposed PHEVs as a potential “compromise” solution to include in the regulation.

An external energy policy expert, who was unaffiliated with the study, called the analysis a “highly valuable addition” after a long period in which segments of the car sector claimed there was insufficient data to accurately evaluate actual emissions.

“The results show, beyond any doubt, that the difference in lab and real-world PHEV fuel consumption and CO₂ output is much, much greater than for gasoline or conventional cars,” they stated. “All policy changes regarding PHEVs should be implemented with extreme caution and considering that data.”