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PHEVs release nearly 5x more planet-heating emissions than official figures show, as per a new analysis.

Growing Discrepancy Between Official and Real-World Emissions

Statistics shows that PHEVs release just one-fifth less CO₂ than traditional petrol and diesel vehicles, according to analysis carried out by a non-profit group. That differs sharply with lab estimates, which assumed a 75% decrease in pollution.

Analysts examined information from in-vehicle fuel consumption meters of 800,000 cars registered in Europe from 2021 and 2023. They found that real-world CO₂ emissions from PHEVs in 2023 were nearly five times greater than lab figures, up from 3.5 times in 2021.

“Actual CO2 output are increasing, while official emissions are falling,” stated a lead analyst involved in the study. “This discrepancy is widening and creates a significant issue. Consequently, PHEVs pollute almost as heavily as gasoline vehicles.”

Key Factors Driving the Discrepancy

Analysts attributed most of the gap to inflated estimates of the “utility factor” – the ratio of kilometers driven in battery mode compared to overall mileage. The team determined that just 27% of driving was completed in electric mode, while official estimates assumed over four-fifths.

Even, when operating in EV mode, pollution amounts were well above lab projections. That happened because electric motors were not strong enough to operate alone, resulting to engines using gasoline for nearly a third of the distance covered in EV mode.

Regulatory and Financial Implications

Based on calculations, the underestimation of PHEV emissions allowed four large automaker groups to escape over €5bn in fines from 2021 and 2023, by artificially simplifying compliance with European Union fleet-average CO₂ standards.

Additionally, drivers of PHEVs could spend about €500 more annually in running costs than would be estimated under lab conditions.

“The bold statements that automakers like to make about their plug-in hybrid cars are clearly way off the mark,” commented a automotive expert. “Consumers are being duped into thinking that by purchasing a PHEV, they are benefiting the environment and saving money. Actually, PHEVs are only slightly better than regular gas and diesel vehicles in terms of energy use, CO₂ emissions, and operating expenses.”

Policy Debate and Automotive Lobbying

Plug-in hybrid vehicles have recently been drawn back into policy discussions as automakers have lobbied the European Union to weaken CO₂ standards. A proposed ban on sales of new combustion engine cars in 2035 has faced heavy pressure from the car sector and opposition from member states with large car industries.

Several high-level officials have suggested PHEVs as a possible “compromise” solution to introduce in the regulation.

An external energy economics specialist, who was unaffiliated with the research, called the analysis a “highly valuable contribution” after a long period in which segments of the automotive industry argued there was insufficient data to properly assess real-world emissions.

“The results show, without question, that the difference in lab and actual PHEV energy use and CO₂ output is much, much larger than for gasoline or conventional cars,” they said. “Any regulatory adjustments regarding PHEVs should be made with utmost caution and considering this data.”