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PHEVs emit almost five times more planet-heating emissions than lab-reported figures show, as per a recent report.

Widening Gap Between Official and Real-World CO2 Output

Data reveals that PHEVs emit just one-fifth lower CO₂ than conventional petrol and diesel cars, based on research conducted by a advocacy group. That differs significantly with lab estimates, which assumed a 75% reduction in emissions.

Researchers studied data from onboard fuel consumption monitors of eight hundred thousand vehicles sold in the EU from 2021 and 2023. They found 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.

“Real-world CO2 output are increasing, while lab-reported emissions are decreasing,” said a senior analyst involved in the study. “This gap is growing and creates a significant issue. Consequently, PHEVs pollute nearly as heavily as gasoline cars.”

Key Reasons Driving the Emissions Gap

Analysts attributed the majority of the difference to inflated estimates of the “utility factor” – the percentage of kilometers travelled in electric mode relative to overall distance. They determined that just 27% of travel was done in electric mode, whereas lab estimates suggested over four-fifths.

Additionally, when operating in electric mode, pollution amounts were significantly higher than lab estimates. That happened because EV motors were insufficiently powerful sufficient to function independently, leading to combustion motors using gasoline for nearly a third of the distance completed in electric mode.

Regulatory and Financial Consequences

According to calculations, the lowballing of PHEV CO2 output enabled four major automaker groups to avoid more than €5bn in fines between 2021 and 2023, by artificially simplifying adherence with European Union fleet-average CO₂ targets.

Furthermore, owners of PHEVs would spend about €500 extra annually in running expenses than would be estimated under laboratory tests.

“The strong claims that automakers often promote about their plug-in hybrid cars are clearly far from the truth,” stated a automotive analyst. “Buyers are being misled into thinking that by purchasing a PHEV, they are helping the planet and saving costs. Actually, PHEVs are only slightly improved than regular gas and diesel cars in terms of energy consumption, CO₂ emissions, and running costs.”

Policy Discussion and Automotive Lobbying

Hybrid cars have recently been drawn back into policy discussions as carmakers have pressed the European Union to weaken CO₂ targets. A proposed ban on sales of new internal combustion cars in 2035 has faced heavy lobbying from the automotive sector and opposition from EU countries with large automotive industries.

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

An independent energy policy expert, who was unaffiliated with the research, called the analysis a “highly valuable addition” after a long period in which segments of the car sector claimed there was insufficient data to properly evaluate actual CO2 output.

“The results show, without question, that the gap in lab and real-world PHEV energy use and CO₂ emissions is much, much greater than for gasoline or diesel vehicles,” they stated. “All policy changes regarding PHEVs should be implemented with extreme caution and considering this data.”