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Plug-in hybrid cars emit almost 5x more global warming pollution than official figures show, as per a new report.

Widening Discrepancy Between Lab and Actual CO2 Output

Statistics shows that PHEVs emit only 19% lower CO₂ than conventional gas and diesel vehicles, based on analysis carried out by a advocacy organization. This differs sharply with laboratory estimates, which suggested a 75% decrease in pollution.

Researchers studied information from onboard fuel consumption meters of 800,000 vehicles sold in the EU between 2021 and 2023. They found that actual CO₂ emissions from PHEVs in 2023 were 4.9 times higher than official figures, increased from 3.5 times in 2021.

“Real-world CO2 output are increasing, while official figures are decreasing,” stated a senior researcher involved in the study. “This discrepancy is growing and creates a serious problem. As a result, PHEVs pollute almost as much as gasoline cars.”

Key Reasons Behind the Discrepancy

Researchers linked the majority of the gap to inflated estimates of the “utility factor” – the ratio of kilometers travelled in battery power compared to overall mileage. The team found that only a quarter of travel was completed in EV mode, whereas official assumptions assumed over four-fifths.

Even, when running in EV mode, emission amounts were significantly higher than official projections. This happened because electric motors were not strong enough to operate independently, leading to engines using gasoline for nearly a third of the travel completed in electric mode.

Policy and Financial Implications

Based on estimates, the lowballing of PHEV CO2 output enabled four major automaker groups to avoid over €5bn in fines between 2021 and 2023, by falsely easing adherence with EU fleet-average CO₂ targets.

Additionally, drivers of PHEVs could spend about €500 extra per year in running costs than is estimated under laboratory conditions.

“The bold statements that manufacturers often promote about their PHEV cars are obviously far from the truth,” stated a automotive expert. “Buyers are being duped into believing that by buying a PHEV, they are helping the planet and cutting costs. Actually, PHEVs are only slightly improved than standard petrol and diesel cars in terms of fuel consumption, CO₂ production, and operating expenses.”

Political Discussion and Industry Pressure

Hybrid vehicles have recently been drawn back into policy debates as automakers have pressed the EU to relax CO₂ standards. A proposed ban on sales of new combustion engine vehicles in 2035 has faced heavy pressure from the automotive sector and resistance from EU countries with large car industries.

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

An independent energy economics expert, who was not involved with the research, called the report a “highly valuable contribution” after a long period in which segments of the car industry claimed there was insufficient information to accurately assess actual CO2 output.

“The results show, without question, that the difference in lab and actual PHEV energy use and CO₂ emissions is significantly greater than for gasoline or diesel cars,” they said. “Any regulatory adjustments regarding PHEVs should be implemented with utmost care and in the light of this data.”