Plug-in Hybrid electric Vehicles Emit Nearly as Heavily as Petrol Vehicles, Report Finds

Plug-in hybrid cars emit nearly 5x more planet-heating pollution than official data show, according to a recent report.

Growing Gap Between Official and Actual Emissions

Data reveals that PHEVs emit just one-fifth less CO₂ than traditional petrol and diesel cars, according to analysis carried out by a advocacy organization. That differs significantly with lab estimates, which assumed a three-quarters decrease in pollution.

Analysts studied data from in-vehicle energy use meters of 800,000 vehicles sold in Europe between 2021 and 2023. They found that real-world CO₂ emissions from PHEVs in 2023 were 4.9 times higher than lab figures, increased from 3.5 times in 2021.

“Real-world CO2 output are increasing, while official figures are falling,” stated a senior analyst involved in the report. “That discrepancy is growing and poses a serious issue. Consequently, PHEVs pollute nearly as heavily as petrol cars.”

Key Reasons Driving the Discrepancy

Analysts linked most of the gap to overestimates of the “utility factor” – the ratio of kilometers travelled in battery mode relative to overall distance. The team determined that just a quarter of driving was done in electric mode, while lab assumptions suggested over four-fifths.

Additionally, when running in electric mode, pollution levels were significantly higher than official projections. That occurred because EV motors were not strong enough to function independently, leading to combustion motors using fossil fuels for nearly a third of the travel covered in EV mode.

Regulatory and Economic Consequences

According to calculations, the lowballing of PHEV emissions allowed several major automaker companies to avoid more than €5bn in fines between 2021 and 2023, by artificially simplifying adherence with European Union fleet-average CO₂ standards.

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

“The strong claims that automakers often promote about their PHEV cars are clearly way off the truth,” stated a transport analyst. “Consumers are being misled into thinking that by purchasing a PHEV, they are helping the environment and cutting costs. Actually, PHEVs are only slightly improved than regular petrol and diesel vehicles in terms of fuel consumption, CO₂ emissions, and running expenses.”

Political Debate and Automotive Lobbying

Plug-in hybrid cars have lately been drawn again into policy discussions as automakers have lobbied the European Union to weaken CO₂ targets. A proposed prohibition on sales of new internal combustion vehicles in 2035 has faced heavy lobbying from the automotive sector and resistance from EU countries with large car industries.

Some high-level politicians have suggested plug-in hybrids as a potential “flexibility” solution to introduce in the regulation.

An external energy economics expert, who was not involved with the study, called the analysis a “very useful addition” after years in which parts of the car sector claimed there was too little data to properly evaluate real-world emissions.

“The results show, without question, that the difference between lab and real-world PHEV energy use and CO₂ output is much, much greater than for gasoline or diesel cars,” they said. “Any regulatory changes regarding PHEVs should be made with utmost caution and in the light of this data.”