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Plug-in hybrid electric vehicles release almost 5x greater global warming emissions than lab-reported figures show, as per a recent report.

Widening Discrepancy Between Lab and Real-World CO2 Output

Statistics reveals that PHEVs emit just one-fifth less CO₂ than traditional gas and diesel vehicles, based on analysis carried out by a advocacy group. This contrasts sharply with laboratory tests, which assumed a three-quarters decrease in pollution.

Researchers examined information from onboard fuel consumption monitors of eight hundred thousand vehicles registered in Europe between 2021 and 2023. They discovered that real-world CO₂ emissions from PHEVs in 2023 were nearly five times higher than lab figures, increased from 3.5 times in 2021.

“Real-world emissions are rising, while lab-reported emissions are falling,” said a lead analyst involved in the study. “This discrepancy is widening and poses a significant problem. Consequently, PHEVs emit almost as heavily as petrol vehicles.”

Key Factors Behind the Discrepancy

Researchers linked most of the gap to inflated estimates of the “utility factor” – the ratio of miles travelled in electric power relative to total distance. They found that only a quarter of driving was done in electric mode, while official estimates assumed over four-fifths.

Additionally, when operating in electric mode, emission amounts were significantly higher than lab projections. This occurred because EV motors were insufficiently powerful enough to function alone, resulting to engines using fossil fuels for almost a third of the distance completed in electric mode.

Regulatory and Financial Consequences

Based on calculations, the underestimation of PHEV emissions allowed several major automaker companies to escape more than €5bn in penalties from 2021 and 2023, by artificially easing adherence with European Union fleet-average CO₂ targets.

Additionally, owners of PHEVs could pay about €500 more per year in running expenses than is assumed under laboratory tests.

“The strong claims that automakers like to make about their PHEV cars are obviously way off the truth,” commented a transport analyst. “Buyers are being duped into thinking that by buying a PHEV, they are helping the planet and cutting costs. Actually, PHEVs are little better than standard petrol and diesel vehicles in terms of fuel use, CO₂ emissions, and operating costs.”

Policy Discussion and Automotive Pressure

Plug-in hybrid cars have recently been brought back into political discussions as automakers have lobbied the European Union to weaken CO₂ standards. A proposed prohibition on sales of new internal combustion vehicles in 2035 has faced intense pressure from the automotive sector and resistance from member states with large automotive industries.

Some high-level politicians have suggested plug-in hybrids as a possible “compromise” option to include in the regulation.

One independent energy economics expert, who was unaffiliated with the research, described the report a “very useful contribution” after years in which parts of the car industry claimed there was insufficient data to properly evaluate real-world emissions.

“These findings demonstrate, beyond any doubt, that the gap between official and real-world PHEV fuel consumption and CO₂ emissions is much, much larger than for petrol or conventional cars,” the expert stated. “All regulatory adjustments concerning PHEVs should be made with utmost care and considering that data.”