Plug-in Hybrid electric Vehicles Pollute Nearly as Heavily as Petrol Cars, Study Finds

Plug-in hybrid electric vehicles release nearly five times greater planet-heating pollution than lab-reported figures show, according to a new analysis.

Growing Discrepancy In Lab and Actual Emissions

Statistics shows that PHEVs release only one-fifth lower CO₂ than conventional gas and diesel vehicles, according to research conducted by a advocacy organization. That contrasts sharply with laboratory tests, which suggested a three-quarters reduction in pollution.

Researchers examined data from onboard energy use monitors of eight hundred thousand vehicles registered in Europe from 2021 and 2023. They found that real-world CO₂ emissions from PHEVs in 2023 were 4.9 times greater than official estimates, up from 3.5 times in 2021.

“Actual emissions are rising, while official figures are falling,” stated a senior analyst participating in the study. “That discrepancy is widening and poses a serious problem. As a result, PHEVs pollute nearly as heavily as petrol cars.”

Primary Factors Behind the Emissions Gap

Researchers attributed most of the gap to inflated estimates of the “electric driving share” – the percentage of kilometers driven in electric mode compared to total mileage. They found that just 27% of travel was completed in electric mode, while lab assumptions suggested 84%.

Even, when running in EV mode, pollution amounts were well above official projections. This occurred because EV motors were insufficiently powerful enough to operate alone, leading to combustion motors using fossil fuels for nearly a third of the travel completed in electric mode.

Policy and Financial Implications

Based on calculations, the underestimation of PHEV emissions allowed several large automaker companies to escape over €5bn in penalties between 2021 and 2023, by artificially simplifying compliance with European Union average fleet CO₂ targets.

Additionally, owners of PHEVs would pay about €500 extra per year in running expenses than is assumed under lab tests.

“The strong claims that manufacturers often promote about their plug-in hybrid cars are obviously far from the mark,” stated a automotive expert. “Buyers are being duped into thinking that by buying a PHEV, they are benefiting the environment and saving money. Actually, PHEVs are only slightly improved than standard petrol and diesel cars in terms of energy use, CO₂ emissions, and operating costs.”

Political Discussion and Industry Lobbying

Hybrid cars have recently been brought back into policy discussions as automakers have lobbied the EU to relax CO₂ standards. A proposed ban on sales of new internal combustion vehicles in 2035 has faced heavy lobbying from the automotive sector and opposition from EU countries with significant car industries.

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

One external energy policy expert, who was unaffiliated with the study, described the analysis a “very useful addition” after a long period in which segments of the automotive industry claimed there was too little information to accurately evaluate actual CO2 output.

“These findings show, beyond any doubt, that the gap in lab and actual PHEV fuel consumption and CO₂ output is significantly larger than for petrol or diesel cars,” they stated. “Any policy adjustments regarding PHEVs should be implemented with extreme care and considering this evidence.”