🔗 Share this article

Plug-in hybrid cars release almost 5x more planet-heating pollution than lab-reported figures show, according to a recent analysis.

Widening Discrepancy Between Lab and Actual Emissions

Statistics reveals that PHEVs emit only 19% lower CO₂ than traditional gas and diesel vehicles, based on analysis carried out by a advocacy organization. That contrasts sharply with laboratory tests, which suggested a three-quarters reduction in pollution.

Analysts studied data from in-vehicle fuel consumption meters of eight hundred thousand vehicles sold in Europe between 2021 and 2023. They found that actual CO₂ output from PHEVs in 2023 were 4.9 times higher than lab estimates, increased from three and a half times in 2021.

“Actual emissions are rising, while lab-reported figures are falling,” stated a lead researcher involved in the report. “This gap is widening and creates a significant issue. Consequently, PHEVs pollute nearly as heavily as petrol vehicles.”

Key Reasons Driving the Emissions Gap

Analysts attributed the majority of the gap to overestimates of the “utility factor” – the ratio of kilometers driven in battery mode relative to total mileage. The team determined that only a quarter of travel was completed in electric mode, while lab estimates suggested over four-fifths.

Additionally, when operating in electric mode, pollution levels were significantly higher than official estimates. That occurred because EV motors were insufficiently powerful enough to function independently, resulting to combustion motors using fossil fuels for almost one-third of the distance completed in EV mode.

Regulatory and Economic Implications

Based on estimates, the underestimation of PHEV emissions enabled several large automaker companies to avoid more than €5bn in penalties from 2021 and 2023, by artificially simplifying compliance with European Union fleet-average CO₂ standards.

Furthermore, drivers of PHEVs would spend about €500 more annually in operating expenses than would be estimated under laboratory tests.

“The bold statements that manufacturers like to make about their PHEV cars are clearly way off the mark,” stated a automotive expert. “Consumers are being duped into thinking that by purchasing a PHEV, they are helping the environment and saving costs. In reality, PHEVs are only slightly better than regular gas and diesel vehicles in terms of fuel use, CO₂ production, and running expenses.”

Political Debate and Industry Pressure

Plug-in hybrid cars have lately been brought again into policy debates as carmakers have lobbied the European Union to weaken CO₂ standards. A planned prohibition on new internal combustion cars in 2035 has faced heavy lobbying from the car industry and resistance from member states with significant car manufacturing.

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

One independent energy economics specialist, who was not involved with the research, called the analysis a “highly valuable addition” after a long period in which segments of the automotive industry argued there was too little information to accurately evaluate real-world emissions.

“The results show, beyond any doubt, that the gap between lab and actual PHEV fuel consumption and CO₂ output is much, much larger than for gasoline or conventional cars,” they stated. “All policy changes regarding PHEVs should be implemented with utmost caution and considering this evidence.”