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Plug-in hybrid electric vehicles emit nearly 5x greater global warming pollution than lab-reported data show, as per a recent analysis.

Widening Discrepancy In Official and Actual CO2 Output

Data shows that PHEVs emit just one-fifth less CO₂ than traditional petrol and diesel vehicles, based on research conducted by a non-profit group. That contrasts significantly with laboratory tests, which assumed a 75% decrease in emissions.

Researchers studied data from in-vehicle fuel consumption meters of 800,000 cars sold in Europe from 2021 and 2023. They discovered that real-world CO₂ output from PHEVs in 2023 were 4.9 times higher than official estimates, up from 3.5 times in 2021.

“Actual emissions are rising, while lab-reported emissions are decreasing,” stated a lead researcher participating in the report. “This discrepancy is widening and poses a serious problem. As a result, PHEVs pollute nearly as much as gasoline vehicles.”

Primary Reasons Driving the Emissions Gap

Analysts attributed most of the difference to overestimates of the “electric driving share” – the percentage of kilometers travelled in battery power relative to total mileage. The team determined that just a quarter of driving was completed in electric mode, whereas lab estimates suggested 84%.

Even, when operating in electric mode, pollution amounts were well above official projections. That occurred because EV motors were not strong sufficient to operate independently, resulting to engines using fossil fuels for almost one-third of the distance covered in EV mode.

Policy and Financial Consequences

According to calculations, the lowballing of PHEV CO2 output allowed several major automaker companies to escape over €5bn in fines from 2021 and 2023, by falsely easing compliance with EU fleet-average CO₂ standards.

Additionally, owners of PHEVs could spend about €500 more per year in running expenses than would be estimated under laboratory conditions.

“The strong statements that manufacturers like to make about their PHEV vehicles are clearly way off the truth,” stated a transport expert. “Buyers are being duped into believing that by purchasing a PHEV, they are benefiting the environment and saving costs. In reality, PHEVs are little improved than regular gas and diesel vehicles in terms of fuel consumption, CO₂ emissions, and operating expenses.”

Political Debate and Industry Pressure

Hybrid cars have recently been brought back into political debates as carmakers have pressed the EU to weaken CO₂ standards. A planned prohibition on new combustion engine vehicles in 2035 has faced heavy pressure from the automotive sector and resistance from member states with significant automotive industries.

Several senior officials have proposed PHEVs as a potential “flexibility” option to include in the legislation.

An external energy policy specialist, who was unaffiliated with the study, described the report a “very useful addition” after a long period in which parts of the automotive industry claimed there was insufficient information to accurately evaluate real-world emissions.

“These findings demonstrate, beyond any doubt, that the gap between lab and real-world PHEV fuel consumption and CO₂ output is significantly greater than for gasoline or conventional vehicles,” the expert stated. “Any policy adjustments regarding PHEVs should be made with extreme caution and considering that evidence.”