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PHEVs produce nearly five times greater planet-heating emissions than lab-reported figures indicate, as per a recent report.

Growing Gap In Official and Actual Emissions

Data shows that PHEVs emit just one-fifth less CO₂ than conventional petrol and diesel cars, according to research carried out by a non-profit group. This contrasts significantly with laboratory tests, which assumed a 75% decrease in pollution.

Analysts examined information from in-vehicle energy use monitors of eight hundred thousand vehicles sold in the EU between 2021 and 2023. The team discovered that actual CO₂ output from PHEVs in 2023 were 4.9 times higher than official figures, up from 3.5 times in 2021.

“Actual emissions are rising, while official figures are decreasing,” said a senior analyst involved in the study. “This discrepancy is growing and poses a significant issue. Consequently, PHEVs pollute almost as heavily as petrol cars.”

Key Reasons Driving the Discrepancy

Researchers attributed the majority of the gap to overestimates of the “utility factor” – the ratio of miles travelled in battery mode relative to overall mileage. They found that only a quarter of travel was done in EV mode, while lab assumptions suggested over four-fifths.

Additionally, when operating in EV mode, pollution levels were significantly higher than official projections. This happened because electric motors were insufficiently powerful sufficient to function independently, resulting to engines burning gasoline for almost a third of the distance covered in EV mode.

Policy and Economic Implications

Based on calculations, the lowballing of PHEV CO2 output enabled several major carmaker companies to avoid over €5bn in penalties from 2021 and 2023, by falsely easing adherence with EU fleet-average CO₂ targets.

Additionally, owners of PHEVs could spend about €500 more annually in operating expenses than would be assumed under laboratory conditions.

“The strong statements that manufacturers often promote about their plug-in hybrid cars are obviously way off the mark,” commented a transport expert. “Consumers are being duped into thinking that by buying a PHEV, they are benefiting the planet and saving costs. In reality, PHEVs are little improved than standard petrol and diesel vehicles in terms of fuel consumption, CO₂ production, and operating expenses.”

Political Debate and Automotive Pressure

Hybrid vehicles have lately been brought back into political debates as carmakers have pressed the EU to relax CO₂ standards. A proposed prohibition on new internal combustion cars in 2035 has faced heavy lobbying from the car sector and resistance from member states with significant automotive industries.

Several senior officials have suggested plug-in hybrids as a potential “compromise” option to include in the regulation.

One external energy policy specialist, who was unaffiliated with the research, described the report a “very useful addition” after years in which segments of the automotive industry claimed there was insufficient information to properly assess real-world CO2 output.

“These findings show, without question, that the difference between lab and real-world PHEV fuel consumption and CO₂ output is much, much greater than for petrol or diesel vehicles,” they said. “Any policy changes regarding PHEVs should be made with extreme caution and considering that evidence.”