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PHEVs emit almost five times greater planet-heating emissions than lab-reported figures show, according to a new analysis.

Widening Gap In Lab and Real-World CO2 Output

Statistics reveals that PHEVs emit only one-fifth lower CO₂ than traditional gas and diesel vehicles, according to research carried out by a non-profit group. This differs significantly with lab estimates, which assumed a 75% decrease in emissions.

Analysts studied data from onboard energy use meters of 800,000 cars registered in the EU between 2021 and 2023. The team found that actual CO₂ output from PHEVs in 2023 were 4.9 times greater than lab estimates, increased from three and a half times in 2021.

“Actual CO2 output are increasing, while official figures are decreasing,” stated a lead analyst involved in the study. “That discrepancy is widening and creates a significant issue. As a result, PHEVs pollute nearly as heavily as gasoline cars.”

Primary Factors Behind the Discrepancy

Analysts linked the majority of the gap to overestimates of the “utility factor” – the percentage of miles driven in electric power relative to overall mileage. They determined that only 27% of driving was completed in EV mode, while official estimates suggested over four-fifths.

Even, when running in EV mode, pollution levels were significantly higher than official projections. This happened because electric motors were insufficiently powerful enough to operate alone, leading to engines burning gasoline for almost one-third of the travel completed in EV mode.

Regulatory and Financial Implications

Based on calculations, the lowballing of PHEV emissions allowed several major carmaker companies to escape more than €5bn in fines between 2021 and 2023, by artificially easing adherence with EU fleet-average CO₂ targets.

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

“The strong statements that manufacturers often promote about their plug-in hybrid cars are clearly way off the truth,” stated a transport expert. “Consumers are being duped into thinking that by buying a PHEV, they are helping the planet and cutting costs. In reality, PHEVs are only slightly better than standard gas and diesel cars in terms of fuel consumption, CO₂ emissions, and running expenses.”

Policy Discussion and Industry Pressure

Plug-in hybrid vehicles have lately been brought back into political discussions as automakers have lobbied the European Union to weaken CO₂ standards. A planned prohibition on sales of new internal combustion vehicles in 2035 has faced intense lobbying from the automotive industry and resistance from EU countries with significant car manufacturing.

Some high-level politicians have proposed plug-in hybrids as a potential “compromise” solution to include in the regulation.

One independent energy policy specialist, who was not involved with the study, described the analysis a “very useful contribution” after years in which segments of the car industry claimed there was too little information to accurately evaluate actual emissions.

“The results demonstrate, without question, that the difference in lab and actual PHEV energy use and CO₂ emissions is significantly greater than for petrol or conventional cars,” the expert stated. “All regulatory changes regarding PHEVs should be implemented with utmost care and considering that evidence.”