🔗 Share this article

Plug-in hybrid electric vehicles release nearly five times greater planet-heating pollution than lab-reported data indicate, as per a recent analysis.

Growing Gap In Official and Real-World CO2 Output

Statistics reveals that PHEVs emit just one-fifth less CO₂ than traditional petrol and diesel vehicles, based on research conducted by a non-profit group. That contrasts sharply with lab estimates, which assumed a 75% reduction in pollution.

Researchers examined information from onboard energy use monitors of 800,000 vehicles sold in the EU between 2021 and 2023. The team discovered that real-world CO₂ emissions from PHEVs in 2023 were nearly five times higher than official figures, up from three and a half times in 2021.

“Actual emissions are increasing, while official emissions are falling,” said a lead analyst participating in the report. “That discrepancy is widening and creates a serious issue. Consequently, PHEVs pollute nearly as heavily as petrol cars.”

Primary Reasons Driving the Discrepancy

Analysts attributed the majority of the gap to overestimates of the “utility factor” – the ratio of kilometers travelled in electric mode compared to total distance. The team determined that only 27% of travel was completed in EV mode, whereas lab assumptions assumed over four-fifths.

Additionally, when operating in electric mode, emission levels were significantly higher than official estimates. This happened because EV motors were not strong sufficient to function independently, resulting to combustion motors burning gasoline for almost one-third of the distance completed in electric mode.

Policy and Economic Implications

Based on calculations, the lowballing of PHEV CO2 output enabled four major carmaker groups to avoid more than €5bn in penalties from 2021 and 2023, by falsely easing compliance with European Union fleet-average CO₂ targets.

Furthermore, drivers of PHEVs could pay about €500 extra annually in running costs than would be estimated under lab conditions.

“The bold claims that automakers like to make about their plug-in hybrid vehicles are obviously way off the truth,” stated a automotive analyst. “Buyers are being misled into thinking that by buying a PHEV, they are helping the planet and cutting money. In reality, PHEVs are little better than regular petrol and diesel vehicles in terms of energy consumption, CO₂ emissions, and operating expenses.”

Policy Discussion and Industry Pressure

Hybrid cars have lately been drawn back into policy discussions as automakers have pressed the European Union to weaken CO₂ targets. A planned ban on sales of new combustion engine cars in 2035 has faced heavy pressure from the automotive sector and opposition from member states with significant car manufacturing.

Some high-level politicians have proposed plug-in hybrids as a potential “compromise” solution to include in the legislation.

One external energy economics expert, who was unaffiliated with the study, described the analysis a “very useful contribution” after years in which parts of the automotive industry argued there was too little data to accurately assess actual CO2 output.

“These findings demonstrate, without question, that the difference between official and actual PHEV fuel consumption and CO₂ output is significantly greater than for petrol or conventional cars,” they said. “All policy changes regarding PHEVs should be implemented with extreme care and in the light of that data.”