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PHEVs produce nearly five times greater planet-heating pollution than lab-reported data indicate, as per a new analysis.

Growing Discrepancy In Official and Actual CO2 Output

Statistics reveals that PHEVs emit only one-fifth less CO₂ than traditional gas and diesel cars, according to analysis conducted by a non-profit organization. That contrasts significantly with laboratory estimates, which suggested a three-quarters decrease in emissions.

Researchers studied information from in-vehicle fuel consumption meters of eight hundred thousand vehicles registered in Europe from 2021 and 2023. The team discovered that actual CO₂ emissions from PHEVs in 2023 were nearly five times higher than official estimates, increased from three and a half times in 2021.

“Actual CO2 output are rising, while official emissions are decreasing,” stated a senior analyst involved in the study. “This discrepancy is widening and poses a serious issue. Consequently, PHEVs emit nearly as heavily as gasoline vehicles.”

Primary Factors Driving the Emissions Gap

Analysts attributed most of the gap to inflated estimates of the “utility factor” – the percentage of miles travelled in battery power relative to total mileage. The team determined that only a quarter of travel was done in EV mode, whereas lab assumptions assumed 84%.

Additionally, when running in electric mode, pollution amounts were significantly higher than official projections. This occurred because EV motors were insufficiently powerful sufficient to operate independently, leading to combustion motors using fossil fuels for almost a third of the travel covered in electric mode.

Policy and Financial Implications

According to calculations, the lowballing of PHEV emissions enabled four major carmaker groups to avoid more than €5bn in penalties from 2021 and 2023, by falsely easing compliance with European Union fleet-average CO₂ standards.

Additionally, owners of PHEVs could spend approximately €500 more per year in running expenses than is estimated under lab tests.

“The bold claims that manufacturers like to make about their plug-in hybrid cars are clearly way off the truth,” commented a transport expert. “Buyers are being misled into thinking that by purchasing a PHEV, they are benefiting the environment and saving costs. Actually, PHEVs are little better than standard petrol and diesel vehicles in terms of energy consumption, CO₂ production, and operating costs.”

Political Discussion and Industry Lobbying

Plug-in hybrid cars have recently been brought again into policy debates as carmakers have lobbied the EU to weaken CO₂ targets. A planned ban on sales of new combustion engine cars in 2035 has faced heavy lobbying from the car industry and resistance from EU countries with large car industries.

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

One external energy economics specialist, who was unaffiliated with the research, called the report a “highly valuable contribution” after a long period in which parts of the car industry claimed there was insufficient information to properly evaluate real-world emissions.

“These findings show, beyond any doubt, that the difference between lab and real-world PHEV fuel consumption and CO₂ output is much, much greater than for gasoline or diesel cars,” the expert said. “Any regulatory changes concerning PHEVs should be made with extreme caution and in the light of that evidence.”