🔗 Share this article

Plug-in hybrid electric vehicles release nearly five times greater planet-heating pollution than lab-reported figures show, according to a recent analysis.

Widening Gap Between Lab and Actual Emissions

Statistics reveals that PHEVs release only one-fifth lower CO₂ than conventional petrol and diesel vehicles, based on analysis carried out by a non-profit group. That differs significantly with laboratory estimates, which assumed a three-quarters reduction in pollution.

Researchers examined data from onboard energy use monitors of 800,000 cars sold in Europe between 2021 and 2023. The team discovered that actual CO₂ emissions from PHEVs in 2023 were 4.9 times higher than lab figures, up from three and a half times in 2021.

“Real-world CO2 output are rising, while lab-reported figures are falling,” said a senior analyst involved in the report. “This gap is growing and poses a serious issue. Consequently, PHEVs emit nearly as much as petrol cars.”

Primary Reasons Driving the Discrepancy

Analysts linked the majority of the gap to overestimates of the “electric driving share” – the percentage of kilometers travelled in battery mode compared to overall distance. The team determined that only 27% of driving was completed in electric mode, while lab estimates assumed 84%.

Additionally, when operating in electric mode, pollution amounts were well above lab projections. This happened because electric motors were not strong enough to operate alone, resulting to engines burning gasoline for almost one-third of the travel covered in EV mode.

Policy and Economic Implications

Based on calculations, the lowballing of PHEV CO2 output enabled several large automaker groups to avoid more than €5bn in penalties from 2021 and 2023, by artificially simplifying compliance with European Union average fleet CO₂ standards.

Additionally, owners of PHEVs would pay approximately €500 more per year in running expenses than is assumed under laboratory tests.

“The bold statements that automakers often promote about their plug-in hybrid cars 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 saving money. Actually, PHEVs are only slightly improved than standard gas and diesel vehicles in terms of energy consumption, CO₂ emissions, and operating costs.”

Political Debate and Automotive Lobbying

Hybrid vehicles have lately been drawn back into policy discussions as carmakers have lobbied the European Union to relax CO₂ targets. A planned ban on new internal combustion cars in 2035 has faced heavy pressure from the car industry and resistance from EU countries with significant automotive manufacturing.

Several senior officials have proposed plug-in hybrids as a potential “compromise” solution to introduce in the regulation.

One external energy economics expert, who was unaffiliated with the research, described the report a “very useful addition” after years in which parts of the automotive sector argued there was insufficient information to accurately assess real-world CO2 output.

“These findings demonstrate, beyond any doubt, that the gap in official and actual PHEV energy use and CO₂ emissions is significantly greater than for gasoline or conventional cars,” they said. “All regulatory adjustments regarding PHEVs should be implemented with extreme caution and considering that data.”