Plug in Hybrid electric Vehicles Pollute Almost as Heavily as Petrol Cars, Report Finds

Plug-in hybrid cars emit almost 5x greater global warming pollution than official figures indicate, according to a recent analysis.

Widening Discrepancy In Official and Real-World CO2 Output

Statistics shows that PHEVs emit only 19% less CO₂ than conventional gas and diesel vehicles, according to analysis conducted by a advocacy organization. That differs sharply with laboratory tests, which assumed a three-quarters decrease in pollution.

Researchers studied data from in-vehicle energy use monitors of eight hundred thousand cars registered in the EU between 2021 and 2023. They discovered that real-world CO₂ emissions from PHEVs in 2023 were 4.9 times greater than official estimates, up from 3.5 times in 2021.

“Actual emissions are increasing, while lab-reported emissions are falling,” said a lead analyst involved in the report. “That gap is widening and poses a serious issue. As a result, PHEVs pollute nearly as heavily as petrol vehicles.”

Key Reasons Behind the Discrepancy

Researchers linked the majority of the gap to inflated estimates of the “utility factor” – the ratio of kilometers driven in battery power compared to total mileage. The team determined that only a quarter of travel was completed in electric mode, while official estimates suggested 84%.

Additionally, when operating in electric mode, pollution amounts were significantly higher than lab estimates. This occurred because EV motors were not strong sufficient to function alone, leading to engines using fossil fuels for almost a third of the distance completed in EV mode.

Regulatory and Financial Implications

Based on estimates, the lowballing of PHEV emissions allowed several large carmaker companies to escape over €5bn in penalties from 2021 and 2023, by falsely easing compliance with European Union average fleet CO₂ targets.

Furthermore, drivers of PHEVs would spend approximately €500 extra per year in running costs than would be assumed under lab conditions.

“The strong statements that automakers often promote about their plug-in hybrid cars are obviously far from the truth,” stated a automotive expert. “Consumers are being duped into thinking that by purchasing a PHEV, they are helping the environment and saving money. In reality, PHEVs are little better than standard petrol and diesel vehicles in terms of energy use, CO₂ production, and running costs.”

Political Debate and Industry Pressure

Plug-in hybrid cars have recently been brought again into political discussions as carmakers have pressed the EU to weaken CO₂ targets. A proposed ban on new internal combustion cars in 2035 has faced heavy pressure from the automotive sector and resistance from member states with large automotive manufacturing.

Several high-level politicians have suggested PHEVs as a possible “flexibility” option to introduce in the legislation.

An external energy economics expert, who was unaffiliated with the study, described the report a “very useful addition” after a long period in which parts of the automotive sector argued there was too little data to properly assess real-world CO2 output.

“These findings show, without question, that the difference between lab and real-world PHEV fuel consumption and CO₂ output is significantly greater than for petrol or diesel cars,” they said. “All regulatory adjustments concerning PHEVs should be made with utmost caution and in the light of this evidence.”