Plug in Hybrid electric Cars Pollute Almost as Much as Petrol Cars, Study Reveals

PHEVs emit almost five times more planet-heating pollution than official figures show, according to a recent report.

Growing Gap Between Official and Actual Emissions

Statistics shows that PHEVs emit only one-fifth lower CO₂ than conventional gas and diesel vehicles, according to analysis carried out by a non-profit group. This differs significantly with lab estimates, which suggested a 75% reduction in pollution.

Analysts studied information from in-vehicle fuel consumption monitors of 800,000 cars registered in Europe from 2021 and 2023. The team found that actual CO₂ output from PHEVs in 2023 were nearly five times greater than official estimates, increased from three and a half times in 2021.

“Actual emissions are rising, while official figures are falling,” stated a lead analyst participating in the report. “That discrepancy is growing and poses a significant problem. Consequently, PHEVs pollute almost as heavily as gasoline vehicles.”

Key Reasons Driving the Emissions Gap

Analysts linked most of the gap to overestimates of the “electric driving share” – the ratio of miles travelled in battery power relative to overall distance. They found that just 27% of driving was completed in electric mode, while official assumptions assumed 84%.

Additionally, when running in EV mode, emission levels were well above official estimates. That happened because EV motors were insufficiently powerful enough to function alone, resulting to combustion motors burning fossil fuels for almost a third of the travel completed in EV mode.

Policy and Financial Consequences

Based on estimates, the underestimation of PHEV CO2 output allowed several major carmaker groups to avoid over €5bn in penalties between 2021 and 2023, by artificially simplifying compliance with EU fleet-average CO₂ targets.

Additionally, owners of PHEVs could pay approximately €500 more per year in running costs than would be assumed under laboratory conditions.

“The strong statements that automakers like to make about their plug-in hybrid vehicles are clearly way off the truth,” commented a transport expert. “Consumers are being misled into thinking that by buying a PHEV, they are benefiting the environment and saving money. In reality, PHEVs are little better than standard petrol and diesel cars in terms of energy consumption, CO₂ production, and operating costs.”

Policy Debate and Automotive Lobbying

Hybrid vehicles have recently been brought again into policy discussions as automakers have pressed the European Union to weaken CO₂ standards. A proposed ban on sales of new internal combustion cars in 2035 has faced intense lobbying from the automotive industry and resistance from EU countries with large car industries.

Several senior politicians have suggested PHEVs as a possible “flexibility” option to include in the legislation.

One independent energy economics specialist, who was unaffiliated with the study, called the analysis a “highly valuable addition” after years in which parts of the car sector claimed there was insufficient data to accurately assess actual CO2 output.

“The results demonstrate, without question, that the gap between lab and actual PHEV fuel consumption and CO₂ output is much, much larger than for petrol or diesel cars,” they stated. “All policy changes concerning PHEVs should be made with utmost care and considering this evidence.”