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Plug-in hybrid cars emit almost 5x more global warming emissions than official data indicate, as per a recent report.

Growing Discrepancy In Lab and Real-World CO2 Output

Data reveals that PHEVs release just 19% lower CO₂ than traditional petrol and diesel cars, based on analysis conducted by a non-profit organization. That contrasts sharply with laboratory tests, which suggested a 75% reduction in emissions.

Analysts studied information from in-vehicle energy use monitors of eight hundred thousand cars sold in the EU from 2021 and 2023. They found that actual CO₂ emissions from PHEVs in 2023 were nearly five times greater than lab estimates, up from 3.5 times in 2021.

“Real-world emissions are rising, while lab-reported emissions are falling,” stated a senior researcher involved in the study. “This discrepancy is growing and creates a serious problem. Consequently, PHEVs pollute nearly as heavily as petrol vehicles.”

Primary Factors Driving the Emissions Gap

Analysts attributed most of the difference to inflated estimates of the “electric driving share” – the percentage of miles driven in electric mode relative to total mileage. The team found that just 27% of travel was completed in electric mode, while official assumptions suggested 84%.

Even, when operating in EV mode, emission levels were significantly higher than lab estimates. This occurred because electric motors were not strong enough to function independently, leading to combustion motors using fossil fuels for almost one-third of the travel completed in electric mode.

Regulatory and Financial Implications

Based on estimates, the lowballing of PHEV CO2 output enabled four major automaker companies to avoid more than €5bn in fines from 2021 and 2023, by falsely easing compliance with EU fleet-average CO₂ targets.

Additionally, owners of PHEVs could pay approximately €500 more per year in operating expenses than is estimated under lab tests.

“The strong statements that automakers like to make about their plug-in hybrid vehicles are clearly far from the mark,” stated a transport analyst. “Buyers are being duped into thinking that by purchasing a PHEV, they are benefiting the planet and cutting costs. Actually, PHEVs are only slightly better than standard gas and diesel cars in terms of fuel use, CO₂ emissions, and operating expenses.”

Policy Discussion and Industry Lobbying

Hybrid cars have lately been drawn back into political discussions as automakers have lobbied the European Union to weaken CO₂ standards. A planned ban on sales of new combustion engine cars in 2035 has faced heavy lobbying from the car industry and resistance from member states with significant automotive manufacturing.

Several high-level officials have suggested plug-in hybrids as a potential “flexibility” solution to include in the regulation.

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

“These findings show, without question, that the gap in lab and actual PHEV fuel consumption and CO₂ emissions is significantly larger than for petrol or conventional vehicles,” the expert stated. “All regulatory adjustments concerning PHEVs should be made with extreme caution and considering this data.”