Plug in Hybrid Vehicles Pollute Nearly as Heavily as Gasoline Cars, Report Reveals

Plug-in hybrid cars produce nearly 5x greater planet-heating emissions than lab-reported figures show, according to a new report.

Widening Gap In Official and Actual CO2 Output

Data reveals that PHEVs release just 19% lower CO₂ than conventional gas and diesel cars, according to analysis carried out by a non-profit group. That differs sharply with lab tests, which assumed a 75% decrease in emissions.

Researchers examined data from in-vehicle energy use monitors of eight hundred thousand cars registered in the EU between 2021 and 2023. They discovered that real-world CO₂ output from PHEVs in 2023 were 4.9 times greater than lab figures, increased from 3.5 times in 2021.

“Real-world emissions are increasing, while lab-reported emissions are decreasing,” stated a senior researcher participating in the report. “This discrepancy is widening and creates a significant issue. As a result, PHEVs pollute nearly as much as gasoline vehicles.”

Key Reasons Behind the Discrepancy

Researchers linked the majority of the gap to inflated estimates of the “utility factor” – the ratio of miles driven in electric mode compared to total distance. The team found that only 27% of travel was completed in electric mode, while lab assumptions suggested over four-fifths.

Additionally, when operating in EV mode, pollution levels were significantly higher than lab projections. That happened because EV motors were not strong enough to operate alone, leading to combustion motors using fossil fuels for nearly one-third of the travel covered in EV mode.

Policy and Economic Consequences

Based on calculations, the lowballing of PHEV CO2 output enabled several major carmaker companies to avoid more than €5bn in penalties between 2021 and 2023, by falsely easing compliance with EU fleet-average CO₂ targets.

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

“The strong statements that manufacturers often promote about their plug-in hybrid cars are clearly way off the mark,” stated a automotive analyst. “Buyers are being misled into believing that by buying a PHEV, they are benefiting the environment and cutting costs. In reality, PHEVs are only slightly better than standard petrol and diesel cars in terms of energy consumption, CO₂ emissions, and operating costs.”

Political Discussion and Automotive Lobbying

Hybrid cars have lately been drawn again into political debates as automakers have pressed the EU to weaken CO₂ standards. A proposed prohibition on new internal combustion cars in 2035 has faced heavy pressure from the automotive sector and resistance from member states with significant automotive industries.

Several high-level politicians have proposed plug-in hybrids as a potential “flexibility” option to include in the regulation.

One external energy economics expert, who was unaffiliated with the research, described the report a “highly valuable addition” after years in which parts of the automotive industry claimed there was insufficient data to properly assess actual CO2 output.

“These findings demonstrate, beyond any doubt, that the difference in lab and actual PHEV fuel consumption and CO₂ output is much, much greater than for gasoline or conventional cars,” they said. “All policy changes concerning PHEVs should be made with utmost care and considering this data.”