🔗 Share this article

Plug-in hybrid electric vehicles emit almost 5x greater global warming emissions than lab-reported figures indicate, according to a new analysis.

Widening Discrepancy Between Lab and Actual CO2 Output

Data shows that PHEVs emit just 19% lower CO₂ than traditional gas and diesel vehicles, based on analysis conducted by a advocacy organization. This differs sharply with laboratory tests, which assumed a 75% decrease in emissions.

Researchers examined data from in-vehicle fuel consumption meters of 800,000 cars registered in Europe from 2021 and 2023. They discovered that real-world CO₂ output from PHEVs in 2023 were nearly five times higher than official figures, increased from 3.5 times in 2021.

“Actual emissions are increasing, while official emissions are decreasing,” stated a senior analyst involved in the report. “This discrepancy is widening and creates a significant issue. As a result, PHEVs emit nearly as much as petrol cars.”

Key Reasons Behind the Discrepancy

Analysts attributed most of the gap to inflated estimates of the “utility factor” – the percentage of miles driven in battery power relative to total distance. They found that just 27% of travel was completed in electric mode, whereas lab estimates suggested over four-fifths.

Additionally, when operating in EV mode, emission amounts were significantly higher than lab projections. This happened because EV motors were insufficiently powerful sufficient to function independently, resulting to combustion motors using fossil fuels for almost a third of the travel completed in EV mode.

Regulatory and Financial Consequences

Based on calculations, the underestimation of PHEV CO2 output allowed several major automaker groups to avoid over €5bn in fines between 2021 and 2023, by artificially easing compliance with European Union average fleet CO₂ standards.

Furthermore, drivers of PHEVs would pay about €500 more per year in operating costs than is assumed under laboratory conditions.

“The strong statements that automakers like to make about their PHEV cars are clearly way off the truth,” stated a transport expert. “Buyers are being misled into believing that by purchasing a PHEV, they are benefiting the environment and saving money. Actually, PHEVs are little better than standard petrol and diesel vehicles in terms of energy consumption, CO₂ emissions, and running costs.”

Political Debate and Automotive Lobbying

Plug-in hybrid vehicles have lately been brought back into policy debates as carmakers have lobbied the EU to weaken CO₂ standards. A proposed prohibition on new combustion engine vehicles in 2035 has faced intense lobbying from the car industry and resistance from EU countries with significant automotive industries.

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

An external energy economics expert, who was unaffiliated with the study, described the report a “highly valuable contribution” after a long period in which parts of the automotive industry argued there was insufficient information to accurately assess real-world emissions.

“These findings show, without question, that the gap in lab and actual PHEV energy use and CO₂ output is much, much greater than for gasoline or diesel cars,” they said. “Any policy adjustments concerning PHEVs should be implemented with utmost caution and in the light of that evidence.”