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Plug-in hybrid electric vehicles emit almost 5x greater planet-heating emissions than lab-reported figures show, according to a recent report.

Growing Discrepancy In Official and Actual CO2 Output

Statistics shows that PHEVs emit just one-fifth lower CO₂ than traditional petrol and diesel vehicles, based on analysis conducted by a advocacy group. This contrasts significantly with lab tests, which assumed a three-quarters decrease in emissions.

Researchers examined data from onboard fuel consumption meters of eight hundred thousand vehicles sold in Europe between 2021 and 2023. They discovered that real-world CO₂ emissions from PHEVs in 2023 were 4.9 times greater than official figures, increased from 3.5 times in 2021.

“Real-world emissions are increasing, while lab-reported emissions are falling,” stated a lead analyst participating in the study. “That discrepancy is growing and creates a serious issue. Consequently, PHEVs pollute almost as heavily as gasoline vehicles.”

Primary Reasons Driving the Discrepancy

Analysts linked the majority of the gap to overestimates of the “utility factor” – the ratio of kilometers travelled in electric mode relative to total mileage. They found that just 27% of driving was done in EV mode, while lab assumptions suggested 84%.

Additionally, when running in electric mode, pollution amounts were significantly higher than official estimates. That occurred because EV motors were not strong sufficient to function independently, leading to engines using fossil fuels for almost one-third of the travel completed in EV mode.

Policy and Financial Consequences

According to estimates, the lowballing of PHEV emissions allowed four major carmaker groups to avoid over €5bn in penalties between 2021 and 2023, by falsely simplifying compliance with European Union average fleet CO₂ standards.

Additionally, drivers of PHEVs would spend about €500 more annually in operating costs than would be assumed under lab tests.

“The bold statements that automakers often promote about their plug-in hybrid cars are clearly way off the truth,” commented a transport expert. “Consumers are being duped into believing that by buying a PHEV, they are benefiting the environment and cutting costs. Actually, PHEVs are only slightly improved than regular petrol and diesel vehicles in terms of energy consumption, CO₂ production, and operating costs.”

Political Debate and Industry Lobbying

Plug-in hybrid cars have lately been brought back into policy discussions as automakers have pressed the European Union to weaken CO₂ standards. A planned prohibition on sales of new internal combustion vehicles in 2035 has faced heavy lobbying from the car sector and resistance from EU countries with significant car industries.

Several high-level officials have suggested PHEVs as a potential “compromise” option to introduce in the regulation.

One external energy economics specialist, who was unaffiliated with the research, called the report a “very useful contribution” after a long period in which parts of the automotive industry claimed there was too little information to properly evaluate actual emissions.

“These findings show, without question, that the difference between official and actual PHEV energy use and CO₂ output is significantly larger than for petrol or conventional vehicles,” the expert stated. “Any policy changes concerning PHEVs should be implemented with extreme caution and considering this evidence.”