Plug in Hybrid electric Vehicles Pollute Nearly as Much as Gasoline Cars, Study Reveals

Plug-in hybrid cars emit nearly five times greater global warming emissions than official data indicate, according to a new analysis.

Widening Gap In Lab and Real-World Emissions

Data shows that PHEVs release only one-fifth lower CO₂ than traditional petrol and diesel cars, based on research conducted by a advocacy group. That contrasts sharply with lab tests, which assumed a 75% decrease in emissions.

Researchers examined data from onboard energy use meters of eight hundred thousand vehicles registered in Europe from 2021 and 2023. The team discovered that actual CO₂ emissions from PHEVs in 2023 were 4.9 times greater than lab estimates, increased from 3.5 times in 2021.

“Real-world emissions are rising, while lab-reported figures are decreasing,” said a senior analyst participating in the report. “That gap is growing and poses a serious problem. Consequently, PHEVs pollute nearly as heavily as gasoline cars.”

Key Reasons Behind the Discrepancy

Researchers attributed the majority of the gap to inflated estimates of the “utility factor” – the percentage of miles travelled in battery power relative to overall distance. They determined that only 27% of driving was completed in EV mode, while lab estimates assumed over four-fifths.

Additionally, when running in EV mode, pollution levels were significantly higher than official projections. This occurred because EV motors were not strong sufficient to function independently, leading to combustion motors burning fossil fuels for almost one-third of the travel covered in electric mode.

Policy and Financial Implications

Based on estimates, the underestimation of PHEV emissions enabled four major automaker companies to escape over €5bn in fines from 2021 and 2023, by artificially easing compliance with EU average fleet CO₂ targets.

Furthermore, drivers of PHEVs could spend about €500 more annually in running costs than is assumed under laboratory conditions.

“The strong claims that automakers often promote about their plug-in hybrid cars are obviously far from the truth,” commented a automotive analyst. “Buyers are being misled into thinking that by buying a PHEV, they are helping the environment and saving costs. In reality, PHEVs are only slightly improved than standard gas and diesel cars in terms of fuel consumption, CO₂ emissions, and operating costs.”

Political Debate and Automotive Pressure

Plug-in hybrid cars have lately been drawn back into political discussions as carmakers have pressed the European Union to weaken CO₂ targets. A proposed prohibition on sales of new combustion engine vehicles in 2035 has faced intense lobbying from the car sector and opposition from EU countries with significant automotive industries.

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

An external energy economics specialist, who was unaffiliated with the research, described the analysis a “highly valuable addition” after a long period in which parts of the car industry claimed there was insufficient information to properly evaluate actual CO2 output.

“These findings show, without question, that the difference in lab and actual PHEV energy use and CO₂ emissions is significantly larger than for gasoline or diesel cars,” they said. “Any regulatory adjustments concerning PHEVs should be made with utmost care and in the light of that data.”