Plug-in Hybrid electric Cars Emit Almost as Much as Petrol Cars, Report Finds

PHEVs produce nearly 5x greater global warming pollution than lab-reported figures show, according to a recent report.

Growing Discrepancy Between Official and Real-World Emissions

Data shows that PHEVs emit just one-fifth less CO₂ than traditional gas and diesel vehicles, according to research carried out by a non-profit group. That contrasts sharply with lab tests, which suggested a three-quarters decrease in emissions.

Analysts examined data from onboard energy use meters of eight hundred thousand vehicles sold in the EU from 2021 and 2023. The team discovered that actual CO₂ emissions from PHEVs in 2023 were 4.9 times greater than lab figures, up from 3.5 times in 2021.

“Real-world CO2 output are rising, while official emissions are falling,” said a lead analyst involved in the report. “That discrepancy is widening and poses a serious issue. As a result, PHEVs pollute almost as heavily as gasoline cars.”

Key Reasons Driving the Discrepancy

Researchers attributed most of the difference to inflated estimates of the “utility factor” – the ratio of kilometers driven in electric power relative to total mileage. They found that only 27% of driving was completed in electric mode, while lab assumptions assumed over four-fifths.

Additionally, when running in electric mode, emission levels were well above official projections. That occurred because electric motors were insufficiently powerful enough to operate independently, resulting to combustion motors using gasoline for nearly a third of the distance completed in electric mode.

Regulatory and Financial Consequences

Based on calculations, the lowballing of PHEV emissions enabled four large automaker groups to escape more than €5bn in penalties between 2021 and 2023, by falsely easing adherence with EU fleet-average CO₂ standards.

Furthermore, drivers of PHEVs would spend about €500 more annually in running expenses than is assumed under laboratory conditions.

“The bold statements that manufacturers like to make about their plug-in hybrid cars are obviously way off the truth,” stated a transport expert. “Buyers are being misled into thinking that by buying a PHEV, they are helping the planet and saving costs. In reality, PHEVs are little improved than standard gas and diesel cars in terms of energy use, CO₂ production, and operating costs.”

Political Discussion and Industry Pressure

Plug-in hybrid cars have recently been drawn again into political discussions as carmakers have pressed the European Union to relax CO₂ targets. A proposed prohibition on new internal combustion vehicles in 2035 has faced intense lobbying from the car sector and resistance from member states with significant automotive industries.

Several high-level politicians have proposed PHEVs as a potential “flexibility” solution to introduce in the regulation.

An independent energy policy specialist, who was unaffiliated with the study, described the analysis a “very useful addition” after years in which parts of the automotive sector claimed there was insufficient data to accurately assess actual CO2 output.

“These findings show, without question, that the difference between lab and actual PHEV fuel consumption and CO₂ emissions is significantly greater than for gasoline or diesel vehicles,” the expert said. “Any policy adjustments concerning PHEVs should be made with extreme caution and considering this evidence.”