Plug-in Hybrid Vehicles Emit Nearly as Heavily as Petrol Vehicles, Study Finds

PHEVs release almost five times greater global warming pollution than official data show, as per a recent report.

Growing Discrepancy In Official and Actual CO2 Output

Data reveals that PHEVs release only one-fifth lower CO₂ than conventional petrol and diesel vehicles, based on research carried out by a non-profit group. This differs significantly with laboratory estimates, which assumed a 75% reduction in emissions.

Analysts studied data from in-vehicle fuel consumption monitors of 800,000 vehicles registered in Europe between 2021 and 2023. They found that actual CO₂ emissions from PHEVs in 2023 were 4.9 times higher than lab estimates, up from three and a half times in 2021.

“Real-world emissions are increasing, while lab-reported figures are decreasing,” stated a senior researcher participating in the report. “That discrepancy is widening and poses a significant problem. As a result, PHEVs pollute almost as much as petrol vehicles.”

Key Reasons Driving the Emissions Gap

Researchers attributed most of the difference to overestimates of the “electric driving share” – the percentage of miles travelled in electric mode relative to total mileage. They determined that just a quarter of travel was completed in electric mode, while lab estimates assumed 84%.

Even, when running in electric mode, pollution amounts were significantly higher than lab estimates. That happened because EV motors were insufficiently powerful sufficient to operate alone, leading to combustion motors using gasoline for almost a third of the travel completed in EV mode.

Regulatory and Financial Implications

Based on estimates, the underestimation of PHEV CO2 output allowed four major carmaker companies to escape over €5bn in fines from 2021 and 2023, by falsely simplifying compliance with EU average fleet CO₂ targets.

Additionally, owners of PHEVs would spend about €500 extra annually in running expenses than would be assumed under lab conditions.

“The strong claims that manufacturers like to make about their PHEV cars are clearly way off the truth,” stated a automotive analyst. “Buyers are being misled into believing that by purchasing a PHEV, they are benefiting the planet and cutting money. Actually, PHEVs are little improved than standard petrol and diesel cars in terms of energy use, CO₂ production, and running costs.”

Political Debate and Industry Pressure

Hybrid vehicles have lately been brought again into policy discussions as carmakers have lobbied the EU to relax CO₂ targets. A proposed prohibition on new internal combustion cars in 2035 has faced heavy pressure from the car sector and resistance from EU countries with large car industries.

Several high-level politicians have suggested PHEVs as a potential “flexibility” solution to introduce in the regulation.

An external energy policy specialist, who was unaffiliated with the study, described the report a “highly valuable addition” after years in which parts of the automotive industry argued there was insufficient information to properly assess real-world emissions.

“These findings show, without question, that the difference between official and actual PHEV fuel consumption and CO₂ output is significantly greater than for petrol or conventional cars,” they said. “Any regulatory changes regarding PHEVs should be made with utmost caution and considering that data.”