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Plug-in hybrid cars release nearly five times greater planet-heating emissions than official figures indicate, as per a new analysis.

Growing Gap Between Official and Actual CO2 Output

Data reveals that PHEVs release only one-fifth less CO₂ than conventional gas and diesel cars, based on research carried out by a advocacy organization. This differs sharply with lab tests, which assumed a 75% decrease in pollution.

Analysts examined data from in-vehicle energy use meters of 800,000 vehicles registered in the EU from 2021 and 2023. The team discovered that real-world CO₂ emissions from PHEVs in 2023 were 4.9 times greater than official estimates, increased from 3.5 times in 2021.

“Actual CO2 output are increasing, while official emissions are decreasing,” stated a lead analyst participating in the report. “That gap is widening and creates a significant issue. As a result, PHEVs pollute almost as much as petrol cars.”

Key Factors Behind the Emissions Gap

Researchers attributed the majority of the gap to overestimates of the “utility factor” – the ratio of miles driven in battery mode compared to total distance. They found that just 27% of driving was completed in electric mode, whereas official assumptions assumed over four-fifths.

Even, when running in electric mode, pollution amounts were significantly higher than official projections. That occurred because EV motors were not strong enough to operate independently, leading to combustion motors burning gasoline for nearly one-third of the travel covered in EV mode.

Regulatory and Economic Implications

Based on estimates, the lowballing of PHEV emissions enabled several major carmaker companies to avoid over €5bn in fines from 2021 and 2023, by artificially simplifying compliance with European Union fleet-average CO₂ targets.

Furthermore, drivers of PHEVs could spend about €500 more per year in operating expenses than is estimated under laboratory tests.

“The bold statements that automakers like to make about their PHEV cars are clearly far from the truth,” commented a automotive analyst. “Consumers are being duped into thinking that by purchasing a PHEV, they are benefiting the planet and cutting money. In reality, PHEVs are little better than regular gas and diesel cars in terms of energy use, CO₂ emissions, and operating costs.”

Policy Discussion and Automotive Lobbying

Plug-in hybrid cars have lately been drawn back into political discussions as automakers have lobbied the EU to relax CO₂ targets. A planned prohibition on sales of new combustion engine vehicles in 2035 has faced intense lobbying from the car industry and opposition from member states with large car manufacturing.

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

One external energy economics expert, who was unaffiliated with the research, called the report a “very useful addition” after years in which parts of the car industry argued there was insufficient information to properly evaluate actual emissions.

“The results demonstrate, beyond any doubt, that the gap between lab and actual PHEV energy use and CO₂ output is significantly larger than for petrol or conventional cars,” they said. “All policy adjustments concerning PHEVs should be made with extreme caution and considering that evidence.”