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Plug-in hybrid cars emit almost five times greater planet-heating pollution than official data show, as per a recent report.

Widening Gap Between Lab and Actual Emissions

Data shows that PHEVs emit just 19% less CO₂ than conventional gas and diesel cars, according to research carried out by a advocacy group. That differs significantly with lab tests, which suggested a three-quarters reduction in emissions.

Analysts examined information from in-vehicle energy use monitors of 800,000 vehicles sold in the EU from 2021 and 2023. The team discovered that actual CO₂ emissions from PHEVs in 2023 were nearly five times greater than lab figures, up from 3.5 times in 2021.

“Actual CO2 output are increasing, while lab-reported emissions are decreasing,” stated a lead analyst involved in the report. “This discrepancy is widening and poses a significant problem. As a result, PHEVs pollute nearly as much as petrol vehicles.”

Primary Factors Behind the Emissions Gap

Researchers linked the majority of the gap to inflated estimates of the “utility factor” – the percentage of kilometers travelled in electric mode relative to overall mileage. They determined that only 27% of driving was completed in EV mode, while official estimates assumed over four-fifths.

Additionally, when running in EV mode, pollution amounts were significantly higher than official projections. This occurred because electric motors were insufficiently powerful sufficient to function alone, resulting to combustion motors burning fossil fuels for almost one-third of the distance completed in electric mode.

Policy and Financial Implications

According to calculations, the lowballing of PHEV emissions enabled several large carmaker groups to avoid over €5bn in fines from 2021 and 2023, by artificially simplifying compliance with EU fleet-average CO₂ standards.

Furthermore, drivers of PHEVs could spend about €500 extra per year in operating costs than is assumed under laboratory conditions.

“The bold claims that automakers like to make about their PHEV cars are clearly far from the mark,” stated a automotive expert. “Consumers are being duped into believing that by purchasing a PHEV, they are benefiting the environment and cutting money. In reality, PHEVs are little better than standard gas and diesel cars in terms of fuel consumption, CO₂ production, and running costs.”

Political Debate and Industry Pressure

Hybrid cars have lately been brought again into political discussions as automakers have lobbied the European Union to weaken CO₂ standards. A planned prohibition on new internal combustion vehicles in 2035 has faced heavy lobbying from the automotive sector and opposition from EU countries with large car industries.

Some high-level officials have proposed plug-in hybrids as a possible “compromise” solution to introduce in the legislation.

An independent energy economics specialist, who was unaffiliated with the study, called the analysis a “very useful addition” after a long period in which segments of the automotive sector argued there was too little data to properly evaluate real-world CO2 output.

“These findings demonstrate, without question, that the gap in lab and actual PHEV fuel consumption and CO₂ output is much, much larger than for petrol or conventional vehicles,” the expert said. “All policy changes regarding PHEVs should be made with utmost care and in the light of that evidence.”