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PHEVs produce almost five times more global warming emissions than lab-reported figures show, as per a recent report.

Widening Gap Between Official and Real-World CO2 Output

Data reveals that PHEVs release only 19% lower CO₂ than traditional petrol and diesel cars, based on analysis conducted by a advocacy group. This contrasts sharply with lab estimates, which assumed a three-quarters reduction in pollution.

Analysts examined information from in-vehicle energy use meters of 800,000 vehicles registered in the EU between 2021 and 2023. They discovered that real-world CO₂ emissions 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 rising, while lab-reported figures are falling,” stated a senior analyst involved in the report. “This gap is growing and creates a serious problem. As a result, PHEVs pollute almost as much as petrol cars.”

Primary Reasons Driving the Discrepancy

Analysts attributed most of the difference to inflated estimates of the “utility factor” – the ratio of miles travelled in electric mode relative to total distance. They determined that only a quarter of travel was completed in electric mode, whereas lab estimates assumed over four-fifths.

Additionally, when operating in electric mode, pollution levels were well above lab projections. This happened because EV motors were insufficiently powerful sufficient to function independently, leading to engines using fossil fuels for nearly a third of the distance covered in EV mode.

Regulatory and Financial Implications

Based on calculations, the underestimation of PHEV emissions allowed several large automaker groups to avoid over €5bn in fines from 2021 and 2023, by artificially simplifying compliance with European Union average fleet CO₂ targets.

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

“The strong claims that automakers often promote about their plug-in hybrid vehicles are clearly far from the truth,” stated a automotive analyst. “Consumers are being duped into believing that by purchasing a PHEV, they are helping the planet and saving costs. Actually, PHEVs are little improved than standard petrol and diesel cars in terms of fuel use, CO₂ emissions, and running costs.”

Political Debate and Industry Pressure

Plug-in hybrid cars have lately been drawn back into political debates as carmakers have lobbied the European Union to relax CO₂ standards. A proposed prohibition on sales of new combustion engine vehicles in 2035 has faced heavy pressure from the car industry and resistance from member states with significant automotive industries.

Some high-level politicians have suggested PHEVs as a potential “compromise” solution to introduce in the legislation.

An independent energy policy specialist, who was not involved with the research, described the analysis a “very useful contribution” after years in which parts of the automotive industry claimed there was too little information to accurately assess real-world emissions.

“These findings show, without question, that the gap between official and real-world PHEV energy use and CO₂ emissions is significantly greater than for petrol or conventional vehicles,” they said. “All regulatory adjustments concerning PHEVs should be made with utmost care and considering this evidence.”