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PHEVs release nearly 5x more planet-heating emissions than official figures show, as per a new analysis.

Growing Discrepancy In Official and Real-World CO2 Output

Data reveals that PHEVs release only one-fifth less CO₂ than conventional petrol and diesel cars, based on analysis carried out by a non-profit group. This contrasts sharply with lab tests, which suggested a 75% decrease in pollution.

Analysts examined information from in-vehicle fuel consumption meters of eight hundred thousand vehicles sold in Europe from 2021 and 2023. They discovered that real-world CO₂ output from PHEVs in 2023 were nearly five times greater than lab figures, increased from 3.5 times in 2021.

“Actual emissions are increasing, while lab-reported figures are falling,” said a senior researcher involved in the study. “That gap is widening and poses a significant issue. As a result, PHEVs pollute almost as heavily as gasoline cars.”

Primary Reasons Driving the Discrepancy

Researchers attributed most of the difference to inflated estimates of the “utility factor” – the ratio of kilometers travelled in battery mode compared to overall mileage. They determined that just 27% of travel was completed in EV mode, whereas official assumptions suggested over four-fifths.

Even, when running in EV mode, pollution amounts were well above official projections. This occurred because EV motors were not strong sufficient to operate independently, resulting to engines using fossil fuels for nearly a third of the distance covered in EV mode.

Policy and Financial Implications

Based on calculations, the underestimation of PHEV CO2 output allowed four major carmaker companies to escape more than €5bn in fines from 2021 and 2023, by artificially easing compliance with EU fleet-average CO₂ standards.

Furthermore, drivers of PHEVs could spend about €500 extra per year in running expenses than would be estimated under lab tests.

“The strong statements that manufacturers often promote about their plug-in hybrid vehicles are obviously far from the mark,” commented a transport analyst. “Buyers are being misled into believing that by buying a PHEV, they are benefiting the planet and saving money. Actually, PHEVs are only slightly better than standard petrol and diesel cars in terms of fuel consumption, CO₂ emissions, and running expenses.”

Policy Discussion and Automotive Pressure

Hybrid cars have lately been drawn back into political discussions as carmakers have pressed the EU to relax CO₂ standards. A planned ban on sales of new internal combustion vehicles in 2035 has faced heavy pressure from the automotive sector and opposition from member states with large car manufacturing.

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

One independent energy economics specialist, who was not involved with the study, described the analysis a “highly valuable contribution” after years in which parts of the automotive sector claimed there was too little data to accurately evaluate actual CO2 output.

“The results demonstrate, without question, that the gap in official and actual PHEV fuel consumption and CO₂ output is significantly larger than for gasoline or conventional vehicles,” the expert said. “Any regulatory adjustments concerning PHEVs should be implemented with extreme caution and in the light of this evidence.”