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Plug-in hybrid electric vehicles release nearly five times greater planet-heating emissions than official figures indicate, as per a recent report.

Widening Gap Between Lab and Real-World Emissions

Statistics shows that PHEVs emit just one-fifth lower CO₂ than traditional petrol and diesel cars, based on research conducted by a non-profit organization. That contrasts sharply with lab tests, which assumed a three-quarters decrease in pollution.

Analysts examined data from onboard energy use meters of eight hundred thousand vehicles sold in Europe between 2021 and 2023. They discovered that actual CO₂ output from PHEVs in 2023 were nearly five times higher than official figures, up from three and a half times in 2021.

“Actual emissions are rising, while official emissions are falling,” said a senior analyst participating in the report. “That gap is widening and creates a significant problem. As a result, PHEVs pollute nearly as heavily as gasoline vehicles.”

Primary Factors Driving the Emissions Gap

Researchers linked most of the gap to overestimates of the “utility factor” – the ratio of kilometers travelled in battery power relative to total distance. They found that only 27% of travel was completed in EV mode, while lab estimates suggested 84%.

Even, when running in electric mode, pollution levels were well above lab estimates. That happened because EV motors were not strong sufficient to function independently, leading to engines using fossil fuels for almost one-third of the distance covered in EV mode.

Regulatory and Financial Implications

According to calculations, the lowballing of PHEV CO2 output allowed four large carmaker groups to avoid over €5bn in fines between 2021 and 2023, by artificially easing adherence with EU fleet-average CO₂ standards.

Furthermore, drivers of PHEVs could spend approximately €500 extra per year in operating expenses than is assumed under lab tests.

“The strong claims that manufacturers like to make about their PHEV vehicles are clearly way off the mark,” commented a automotive analyst. “Buyers are being misled into believing that by purchasing a PHEV, they are helping the planet and cutting money. In reality, PHEVs are little improved than regular gas and diesel vehicles in terms of energy consumption, CO₂ emissions, and operating costs.”

Political Discussion and Industry Lobbying

Hybrid cars have recently been brought back into policy debates as carmakers have pressed the European Union to relax CO₂ standards. A proposed prohibition on sales of new internal combustion vehicles in 2035 has faced heavy lobbying from the car sector and opposition from member states with significant car manufacturing.

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

One external energy economics specialist, who was unaffiliated with the research, called the analysis a “highly valuable contribution” after a long period in which parts of the car industry argued there was insufficient information to properly assess real-world CO2 output.

“These findings show, beyond any doubt, that the gap between official and real-world PHEV fuel consumption and CO₂ output is much, much greater than for gasoline or conventional vehicles,” the expert said. “All regulatory adjustments regarding PHEVs should be made with extreme caution and considering this evidence.”