Plug-in Hybrid electric Vehicles Emit Nearly as Much as Petrol Cars, Report Reveals

Plug-in hybrid electric vehicles release almost five times greater planet-heating pollution than lab-reported figures show, according to a new report.

Growing Gap In Official and Real-World CO2 Output

Data shows that PHEVs emit just 19% lower CO₂ than traditional petrol and diesel vehicles, based on analysis conducted by a non-profit organization. This differs significantly with lab tests, which suggested a 75% decrease in emissions.

Analysts studied information from in-vehicle energy use meters of 800,000 cars registered in the EU between 2021 and 2023. They discovered that actual CO₂ emissions from PHEVs in 2023 were 4.9 times higher than lab estimates, increased from three and a half times in 2021.

“Actual CO2 output are rising, while official figures are falling,” stated a senior analyst involved in the report. “This discrepancy is growing and creates a significant issue. As a result, PHEVs emit nearly as much as petrol cars.”

Primary Reasons Behind the Discrepancy

Analysts linked most of the gap to overestimates of the “utility factor” – the ratio of kilometers driven in battery mode compared to total mileage. They determined that just a quarter of travel was completed in electric mode, while lab assumptions assumed over four-fifths.

Even, when running in electric mode, pollution amounts were well above lab estimates. This occurred because electric motors were not strong sufficient to function alone, resulting to engines using fossil fuels for nearly one-third of the distance covered in EV mode.

Regulatory and Economic Implications

Based on estimates, the underestimation of PHEV CO2 output enabled four large carmaker companies to avoid more than €5bn in fines from 2021 and 2023, by falsely simplifying compliance with EU fleet-average CO₂ standards.

Additionally, owners of PHEVs could pay about €500 extra per year in operating costs than would be estimated under lab conditions.

“The strong statements that manufacturers often promote about their plug-in hybrid cars are clearly way off the truth,” stated a automotive analyst. “Buyers are being duped into believing that by buying a PHEV, they are benefiting the planet and cutting costs. Actually, PHEVs are little improved than regular gas and diesel cars in terms of fuel consumption, CO₂ production, and running costs.”

Policy Discussion and Industry Lobbying

Hybrid vehicles have lately been brought again into policy debates as carmakers have lobbied the European Union to weaken CO₂ targets. A planned ban on sales of new combustion engine cars in 2035 has faced intense lobbying from the car sector and resistance from EU countries with significant automotive manufacturing.

Several senior politicians have suggested plug-in hybrids as a possible “flexibility” option to introduce in the regulation.

One external energy policy expert, who was unaffiliated with the research, called the report a “very useful contribution” after a long period in which parts of the car sector argued there was insufficient data to accurately assess real-world CO2 output.

“These findings demonstrate, beyond any doubt, that the gap in official and real-world PHEV fuel consumption and CO₂ output is significantly larger than for gasoline or diesel vehicles,” the expert stated. “All regulatory adjustments regarding PHEVs should be implemented with utmost caution and in the light of this data.”