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Plug-in hybrid electric vehicles emit nearly five times greater planet-heating pollution than official figures show, as per a recent analysis.

Widening Gap Between Lab and Actual CO2 Output

Data reveals that PHEVs emit only 19% less CO₂ than conventional gas and diesel vehicles, based on research conducted by a advocacy group. This contrasts sharply with laboratory estimates, which suggested a three-quarters reduction in pollution.

Analysts examined data from onboard fuel consumption meters of 800,000 cars sold in Europe between 2021 and 2023. They found that actual CO₂ emissions from PHEVs in 2023 were 4.9 times higher than lab figures, up from 3.5 times in 2021.

“Actual CO2 output are increasing, while lab-reported emissions are falling,” stated a lead researcher involved in the study. “That discrepancy is widening and creates a serious problem. As a result, PHEVs pollute almost as much as petrol cars.”

Primary Reasons Driving the Emissions Gap

Analysts linked the majority of the gap to inflated estimates of the “electric driving share” – the percentage of kilometers driven in battery mode relative to overall mileage. They found that only a quarter of driving was completed in EV mode, whereas official estimates assumed over four-fifths.

Even, when operating in electric mode, pollution amounts were significantly higher than official estimates. That happened because EV motors were not strong sufficient to operate independently, leading to combustion motors using fossil fuels for almost one-third of the distance completed in EV mode.

Policy and Financial Consequences

According to estimates, the underestimation of PHEV CO2 output allowed several major carmaker companies to avoid more than €5bn in fines from 2021 and 2023, by falsely easing adherence with European Union fleet-average CO₂ standards.

Additionally, drivers of PHEVs could spend about €500 extra annually in running expenses than would be estimated under lab tests.

“The strong statements that manufacturers often promote about their plug-in hybrid cars are obviously way off the mark,” stated a automotive expert. “Consumers are being misled into thinking that by purchasing a PHEV, they are benefiting the environment and cutting money. In reality, PHEVs are little better than standard gas and diesel vehicles in terms of fuel use, CO₂ emissions, and running costs.”

Policy Discussion and Automotive Pressure

Plug-in hybrid vehicles have lately been brought again into political debates as automakers have pressed the European Union to relax CO₂ standards. A proposed ban on sales of new internal combustion cars in 2035 has faced intense lobbying from the car sector and opposition from EU countries with large car industries.

Several senior officials have proposed plug-in hybrids as a possible “compromise” option to include in the legislation.

One independent energy economics specialist, who was not involved with the study, described the report a “highly valuable addition” after years in which segments of the car sector claimed there was insufficient data to accurately assess actual CO2 output.

“These findings show, beyond any doubt, that the difference in lab and actual PHEV fuel consumption and CO₂ emissions is much, much larger than for petrol or diesel cars,” the expert stated. “Any policy adjustments concerning PHEVs should be made with utmost care and in the light of this data.”