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Plug-in hybrid cars emit nearly 5x more planet-heating emissions than lab-reported figures show, as per a recent report.

Growing Discrepancy In Official and Actual Emissions

Statistics reveals that PHEVs emit just one-fifth lower CO₂ than traditional gas and diesel cars, according to analysis carried out by a advocacy group. This differs significantly with lab tests, which assumed a three-quarters decrease in emissions.

Researchers studied data from in-vehicle 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 nearly five times greater than lab estimates, up from three and a half times in 2021.

“Real-world CO2 output are increasing, while lab-reported emissions are decreasing,” said a senior researcher involved in the study. “This gap is widening and poses a significant issue. As a result, PHEVs emit nearly as much as petrol vehicles.”

Key Reasons Behind the Emissions Gap

Analysts attributed the majority of the gap to overestimates of the “utility factor” – the percentage of kilometers driven in battery power relative to overall distance. The team determined that just 27% of driving was done in EV mode, whereas lab estimates suggested over four-fifths.

Additionally, when operating in electric mode, pollution amounts were well above lab estimates. That occurred because EV motors were insufficiently powerful sufficient to operate independently, leading to engines burning fossil fuels for almost a third of the travel completed in EV mode.

Policy and Economic Implications

Based on calculations, the underestimation of PHEV emissions enabled four major carmaker companies to escape over €5bn in fines from 2021 and 2023, by falsely simplifying compliance with EU average fleet CO₂ targets.

Additionally, drivers of PHEVs could pay about €500 more annually in operating expenses than would be assumed under laboratory tests.

“The strong claims that automakers like to make about their PHEV vehicles are obviously far from the truth,” commented a transport analyst. “Buyers are being duped into thinking that by purchasing a PHEV, they are helping the environment and saving costs. In reality, PHEVs are only slightly improved than standard gas and diesel cars in terms of fuel consumption, CO₂ emissions, and operating expenses.”

Policy Debate and Automotive Pressure

Hybrid vehicles have recently been drawn back into political debates as automakers have pressed the European Union to relax CO₂ targets. A planned prohibition on new internal combustion vehicles in 2035 has faced heavy lobbying from the automotive industry and opposition from member states with large automotive manufacturing.

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

An external energy economics specialist, who was unaffiliated with the research, described the report a “very useful addition” after years in which segments 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 between official and real-world PHEV energy use and CO₂ output is significantly greater than for gasoline or diesel vehicles,” they stated. “Any regulatory changes regarding PHEVs should be implemented with utmost care and in the light of that data.”