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Plug-in hybrid electric vehicles produce nearly five times more planet-heating emissions than lab-reported figures indicate, as per a recent analysis.

Widening Gap In Official and Real-World CO2 Output

Data shows that PHEVs release just 19% lower CO₂ than conventional gas and diesel vehicles, according to analysis conducted by a advocacy organization. This differs significantly with lab estimates, which assumed a three-quarters decrease in pollution.

Researchers studied data from onboard energy use meters of eight hundred thousand vehicles sold in the EU between 2021 and 2023. The team discovered that actual CO₂ output from PHEVs in 2023 were 4.9 times greater than official estimates, increased from 3.5 times in 2021.

“Real-world emissions are rising, while official figures are falling,” stated a lead analyst involved in the study. “This gap is widening and creates a serious issue. As a result, PHEVs pollute almost as much as gasoline vehicles.”

Primary Reasons Driving the Discrepancy

Researchers attributed the majority of the gap to inflated estimates of the “utility factor” – the percentage of miles driven in battery mode relative to total mileage. The team found that only a quarter of driving was done in EV mode, while official assumptions assumed over four-fifths.

Additionally, when operating in EV mode, emission amounts were well above lab projections. This happened because electric motors were insufficiently powerful sufficient to function alone, leading to engines using fossil fuels for nearly one-third of the distance covered in EV mode.

Regulatory and Economic Implications

According to estimates, the underestimation of PHEV CO2 output enabled several large automaker groups to escape over €5bn in fines from 2021 and 2023, by artificially simplifying compliance with European Union average fleet CO₂ targets.

Furthermore, owners of PHEVs would spend about €500 extra per year in operating expenses than would be 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 thinking that by purchasing a PHEV, they are benefiting the planet and saving costs. In reality, PHEVs are little improved than standard gas and diesel vehicles in terms of fuel use, CO₂ emissions, and running expenses.”

Policy Discussion and Industry Pressure

Plug-in hybrid cars have lately been brought again into political debates as automakers have lobbied the EU to relax CO₂ standards. A planned ban on sales of new combustion engine vehicles in 2035 has faced heavy pressure from the automotive sector and opposition from EU countries with large car manufacturing.

Several senior officials have proposed plug-in hybrids as a possible “flexibility” option to include in the legislation.

An independent energy policy expert, who was unaffiliated with the research, described the analysis a “very useful addition” after a long period in which parts of the automotive sector argued there was too little information to accurately assess real-world CO2 output.

“The results demonstrate, beyond any doubt, that the gap between lab and actual PHEV fuel consumption and CO₂ output is significantly greater than for petrol or conventional vehicles,” they stated. “All policy adjustments concerning PHEVs should be made with extreme care and considering this evidence.”