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Plug-in hybrid electric vehicles emit almost five times more planet-heating emissions than official data indicate, as per a new report.

Growing Discrepancy In Lab and Actual Emissions

Statistics reveals that PHEVs release only 19% less CO₂ than conventional petrol and diesel vehicles, based on research carried out by a advocacy organization. That differs significantly with laboratory tests, which assumed a three-quarters reduction in emissions.

Analysts studied data from onboard energy use meters of eight hundred thousand cars registered in Europe between 2021 and 2023. They found that real-world CO₂ output from PHEVs in 2023 were nearly five times greater than lab figures, up from three and a half times in 2021.

“Real-world CO2 output are rising, while official emissions are decreasing,” stated a senior analyst participating in the study. “That gap is growing and poses a serious issue. As a result, PHEVs pollute nearly as much as petrol vehicles.”

Primary Reasons Driving the Emissions Gap

Analysts linked most of the gap to overestimates of the “utility factor” – the percentage of kilometers driven in electric power compared to overall mileage. They determined that just 27% of driving was completed in electric mode, while lab estimates suggested 84%.

Additionally, when operating in electric mode, pollution levels were well above lab estimates. That occurred because electric motors were not strong enough to function independently, resulting to combustion motors burning gasoline for almost a third of the travel covered in EV mode.

Policy and Economic Implications

Based on calculations, the underestimation of PHEV CO2 output enabled four major carmaker companies to avoid over €5bn in penalties between 2021 and 2023, by falsely easing adherence with European Union fleet-average CO₂ standards.

Furthermore, drivers of PHEVs would pay approximately €500 more annually in operating expenses than is estimated under laboratory conditions.

“The bold claims that automakers like to make about their plug-in hybrid cars are obviously far from the mark,” stated a automotive analyst. “Buyers are being misled into thinking that by purchasing a PHEV, they are helping the environment and cutting costs. Actually, PHEVs are only slightly better than standard petrol and diesel vehicles in terms of fuel use, CO₂ production, and running expenses.”

Political Debate and Industry Pressure

Hybrid vehicles have recently been drawn back into political debates as automakers have lobbied the EU to weaken CO₂ targets. A planned ban on new internal combustion cars in 2035 has faced heavy pressure from the automotive industry and resistance from member states with large car industries.

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

An independent energy economics expert, who was unaffiliated with the study, called the report a “highly valuable addition” after a long period in which parts of the automotive industry argued there was too little data to accurately evaluate actual CO2 output.

“These findings show, beyond any doubt, that the gap in official and actual PHEV fuel consumption and CO₂ emissions is much, much larger than for gasoline or diesel vehicles,” the expert stated. “Any regulatory adjustments concerning PHEVs should be implemented with utmost care and in the light of this evidence.”