Plug in Hybrid electric Cars Pollute Nearly as Heavily as Gasoline Cars, Study Finds

Plug-in hybrid cars emit nearly 5x more planet-heating emissions than lab-reported data show, according to a recent report.

Growing Discrepancy In Official and Real-World Emissions

Data reveals that PHEVs emit only one-fifth less CO₂ than traditional petrol and diesel cars, according to research carried out by a non-profit group. That differs significantly with lab tests, which suggested a three-quarters reduction in emissions.

Researchers studied data from in-vehicle energy use monitors of 800,000 vehicles sold in the EU between 2021 and 2023. The team discovered that real-world CO₂ output from PHEVs in 2023 were 4.9 times greater than official estimates, increased from 3.5 times in 2021.

“Actual emissions are increasing, while official emissions are falling,” said a senior analyst involved in the report. “That discrepancy is widening and poses a significant issue. As a result, PHEVs emit nearly as much as gasoline cars.”

Key Factors Driving the Emissions Gap

Researchers attributed most of the difference to overestimates of the “utility factor” – the ratio of kilometers driven in electric power compared to overall distance. They found that just 27% of driving was done in electric mode, while lab assumptions assumed over four-fifths.

Even, when running in EV mode, emission amounts were well above lab estimates. That occurred because electric motors were insufficiently powerful sufficient to operate independently, leading to engines burning gasoline for nearly one-third of the travel covered in EV mode.

Regulatory and Economic Consequences

Based on estimates, the lowballing of PHEV CO2 output allowed four large carmaker groups to escape over €5bn in fines between 2021 and 2023, by falsely easing compliance with EU average fleet CO₂ standards.

Additionally, drivers of PHEVs would pay approximately €500 extra per year in operating expenses than is assumed under laboratory conditions.

“The strong statements that automakers often promote about their plug-in hybrid vehicles are obviously way off the truth,” commented a automotive expert. “Consumers are being duped into thinking that by purchasing a PHEV, they are helping the planet and cutting costs. In reality, PHEVs are only slightly better than standard gas and diesel vehicles in terms of energy consumption, CO₂ emissions, and operating costs.”

Policy Debate and Automotive Pressure

Hybrid cars have recently been brought back into political debates as carmakers have pressed the EU to relax CO₂ standards. A planned ban on new internal combustion vehicles in 2035 has faced intense pressure from the car sector and resistance from member states with significant automotive manufacturing.

Some high-level officials have suggested plug-in hybrids as a possible “compromise” solution to include in the legislation.

An independent energy policy specialist, who was unaffiliated with the study, described the analysis a “very useful addition” after a long period in which parts of the automotive industry claimed there was too little data to accurately evaluate actual CO2 output.

“These findings demonstrate, without question, that the gap in lab and actual PHEV fuel consumption and CO₂ emissions is much, much larger than for petrol or diesel vehicles,” they stated. “All policy changes concerning PHEVs should be made with utmost care and considering this evidence.”