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PHEVs produce nearly five times more global warming emissions than lab-reported data indicate, as per a new analysis.

Growing Gap In Official and Actual CO2 Output

Statistics reveals that PHEVs emit only one-fifth less CO₂ than traditional gas and diesel vehicles, according to analysis conducted by a non-profit organization. That contrasts sharply with laboratory estimates, which suggested a three-quarters decrease in emissions.

Researchers examined information from in-vehicle fuel consumption meters of 800,000 cars sold in Europe between 2021 and 2023. They found that actual CO₂ emissions from PHEVs in 2023 were nearly five times higher than lab estimates, up from 3.5 times in 2021.

“Actual emissions are increasing, while official figures are decreasing,” stated a senior analyst involved in the report. “This discrepancy is widening and creates a significant problem. As a result, PHEVs pollute nearly as heavily as gasoline cars.”

Primary Factors Driving the Emissions Gap

Analysts attributed most of the gap to overestimates of the “electric driving share” – the percentage of miles driven in battery power compared to total distance. They found that just a quarter of travel was completed in electric mode, whereas lab estimates assumed 84%.

Even, when running in electric mode, pollution levels were significantly higher than official estimates. This occurred because electric motors were insufficiently powerful sufficient to function alone, leading to combustion motors using gasoline for nearly one-third of the travel completed in electric mode.

Regulatory and Financial Implications

Based on calculations, the lowballing of PHEV emissions enabled several large automaker companies to avoid more than €5bn in penalties between 2021 and 2023, by artificially simplifying adherence with EU average fleet CO₂ targets.

Furthermore, owners of PHEVs could pay about €500 more annually in running costs than would be assumed under laboratory conditions.

“The bold statements that automakers often promote about their plug-in hybrid vehicles are clearly far from the truth,” commented a transport expert. “Buyers are being duped into thinking that by buying a PHEV, they are benefiting the planet and saving costs. In reality, PHEVs are only slightly better than regular petrol and diesel cars in terms of fuel use, CO₂ production, and operating expenses.”

Political Discussion and Automotive Pressure

Hybrid vehicles have lately been drawn back into political discussions as automakers have lobbied the European Union to relax CO₂ targets. A proposed prohibition on sales of new combustion engine cars in 2035 has faced heavy lobbying from the automotive industry and opposition from member states with large car industries.

Some senior politicians have proposed plug-in hybrids as a potential “flexibility” solution to introduce in the regulation.

One external energy economics specialist, who was unaffiliated with the research, called the report a “very useful contribution” after years in which parts of the automotive sector argued there was insufficient data to properly evaluate real-world CO2 output.

“These findings demonstrate, without question, that the difference in lab and actual PHEV energy use and CO₂ output is much, much greater than for petrol or conventional cars,” the expert said. “All regulatory adjustments concerning PHEVs should be made with utmost care and in the light of that evidence.”