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PHEVs produce almost 5x more global warming pollution than lab-reported figures show, as per a recent analysis.

Widening Discrepancy Between Lab and Actual CO2 Output

Statistics reveals that PHEVs emit just 19% lower CO₂ than conventional petrol and diesel vehicles, according to research conducted by a non-profit group. That differs sharply with laboratory estimates, which assumed a 75% decrease in emissions.

Researchers studied data from onboard energy use meters of eight hundred thousand vehicles registered in Europe from 2021 and 2023. The team discovered that actual CO₂ emissions from PHEVs in 2023 were nearly five times greater than official figures, increased from three and a half times in 2021.

“Actual CO2 output are increasing, while lab-reported figures are decreasing,” stated a senior researcher participating in the report. “That discrepancy is widening and creates a serious issue. Consequently, PHEVs emit almost as heavily as gasoline vehicles.”

Primary Factors Behind the Emissions Gap

Researchers attributed the majority of the difference to inflated estimates of the “electric driving share” – the percentage of kilometers travelled in battery mode relative to total mileage. They determined that just 27% of driving was done in electric mode, whereas lab assumptions suggested 84%.

Additionally, when running in EV mode, emission amounts were significantly higher than official estimates. This happened because electric motors were insufficiently powerful enough to operate alone, leading to combustion motors using fossil fuels for nearly one-third of the travel completed in EV mode.

Regulatory and Financial Implications

According to estimates, the lowballing of PHEV CO2 output enabled several major carmaker groups to avoid more than €5bn in penalties between 2021 and 2023, by artificially easing adherence with European Union average fleet CO₂ targets.

Furthermore, owners of PHEVs would pay about €500 extra per year in operating costs than would be assumed under laboratory tests.

“The strong claims that automakers like to make about their PHEV cars are obviously way off the truth,” commented a transport expert. “Buyers are being duped into believing that by purchasing a PHEV, they are helping the environment and saving costs. In reality, PHEVs are only slightly better than regular petrol and diesel cars in terms of fuel consumption, CO₂ production, and operating expenses.”

Policy Debate and Automotive Lobbying

Hybrid vehicles have recently been drawn again into policy debates as carmakers have pressed the European Union to weaken CO₂ standards. A planned ban on sales of new internal combustion vehicles in 2035 has faced intense lobbying from the automotive sector and opposition from member states with significant car industries.

Several high-level politicians have proposed PHEVs as a possible “flexibility” solution to include in the legislation.

One independent energy economics expert, who was unaffiliated with the study, described the report a “highly valuable addition” after years in which parts of the automotive sector argued there was too little information to properly evaluate real-world CO2 output.

“The results demonstrate, without question, that the difference between official and actual PHEV energy use and CO₂ output is much, much larger than for petrol or diesel cars,” the expert stated. “Any policy changes regarding PHEVs should be implemented with extreme caution and considering this data.”