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PHEVs emit nearly 5x greater planet-heating emissions than official data show, as per a new analysis.

Widening Gap In Official and Actual Emissions

Statistics shows that PHEVs emit only one-fifth less CO₂ than traditional gas and diesel cars, according to research carried out by a non-profit group. This contrasts significantly with lab estimates, which suggested a 75% reduction in emissions.

Analysts studied information from in-vehicle energy use monitors of 800,000 vehicles sold in Europe from 2021 and 2023. They discovered that real-world CO₂ emissions from PHEVs in 2023 were nearly five times higher than official estimates, up from three and a half times in 2021.

“Actual emissions are rising, while official figures are decreasing,” stated a lead analyst participating in the study. “That gap is widening and creates a significant problem. Consequently, PHEVs pollute almost as heavily as petrol cars.”

Primary Factors Driving the Discrepancy

Analysts linked most of the difference to overestimates of the “electric driving share” – the percentage of miles driven in battery power compared to total mileage. The team found that only 27% of driving was done in EV mode, while official estimates suggested 84%.

Additionally, when operating in electric mode, pollution levels were well above lab estimates. This occurred because EV motors were not strong enough to function alone, leading to engines using fossil fuels for nearly a third of the distance covered in electric mode.

Policy and Financial Implications

Based on calculations, the lowballing of PHEV emissions allowed several major automaker groups to escape more than €5bn in penalties between 2021 and 2023, by falsely simplifying compliance with EU fleet-average CO₂ targets.

Additionally, drivers of PHEVs would pay about €500 extra annually in operating expenses than is assumed under lab tests.

“The bold statements that manufacturers often promote about their plug-in hybrid cars are clearly way off the truth,” stated a transport expert. “Consumers are being duped into believing that by purchasing a PHEV, they are helping the environment and cutting money. In reality, PHEVs are only slightly better than regular gas and diesel cars in terms of energy use, CO₂ emissions, and operating expenses.”

Political Debate and Industry Lobbying

Plug-in hybrid cars have lately been brought again into policy debates as automakers have lobbied the EU to relax CO₂ targets. A proposed prohibition on new internal combustion vehicles in 2035 has faced intense lobbying from the car industry and opposition from EU countries with significant automotive manufacturing.

Several high-level politicians have proposed plug-in hybrids as a possible “compromise” option to include in the legislation.

An external energy economics expert, who was not involved with the research, described the report a “highly valuable addition” after a long period in which parts of the automotive industry argued there was insufficient information to properly evaluate actual emissions.

“The results demonstrate, beyond any doubt, that the difference between official and actual PHEV energy use and CO₂ output is much, much greater than for gasoline or conventional vehicles,” they said. “Any regulatory changes concerning PHEVs should be made with utmost caution and in the light of that data.”