🔗 Share this article

Plug-in hybrid electric vehicles release nearly five times greater global warming pollution than official figures show, as per a new report.

Growing Gap Between Official and Real-World Emissions

Data reveals that PHEVs release only 19% less CO₂ than conventional gas and diesel vehicles, based on analysis carried out by a advocacy organization. That contrasts significantly with laboratory tests, which assumed a three-quarters decrease in emissions.

Researchers examined information from onboard fuel consumption monitors of eight hundred thousand vehicles sold in the EU between 2021 and 2023. The team found that actual CO₂ emissions from PHEVs in 2023 were 4.9 times higher than lab estimates, increased from three and a half times in 2021.

“Real-world emissions are increasing, while lab-reported figures are falling,” said a lead researcher involved in the report. “This discrepancy is growing and poses a serious issue. As a result, PHEVs emit nearly as heavily as gasoline cars.”

Primary Reasons Behind the Emissions Gap

Analysts linked the majority of the difference to overestimates of the “electric driving share” – the ratio of miles travelled in battery mode compared to overall distance. The team found that only 27% of driving was done in EV mode, whereas lab estimates assumed over four-fifths.

Additionally, when running in EV mode, emission amounts were significantly higher than lab projections. That occurred because EV motors were not strong enough to operate alone, leading to engines using fossil fuels for nearly one-third of the distance covered in EV mode.

Regulatory and Financial Consequences

Based on estimates, the lowballing of PHEV emissions enabled four major automaker companies to escape more than €5bn in fines between 2021 and 2023, by falsely easing adherence with EU average fleet CO₂ targets.

Additionally, drivers of PHEVs could spend about €500 more per year in running costs than would be estimated under lab tests.

“The strong statements that manufacturers like to make about their PHEV vehicles are obviously far from the truth,” stated a transport expert. “Buyers are being misled into believing that by buying a PHEV, they are helping the environment and cutting costs. In reality, PHEVs are little improved than regular petrol and diesel vehicles in terms of fuel use, CO₂ production, and running expenses.”

Policy Debate and Industry Lobbying

Hybrid cars have recently been drawn again into political 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 industry and opposition from EU countries with large car manufacturing.

Some high-level officials have suggested PHEVs as a potential “flexibility” solution to include in the legislation.

One independent energy economics expert, who was not involved with the study, described the report a “highly valuable contribution” after a long period in which segments of the car industry claimed there was insufficient information to accurately evaluate actual emissions.

“The results show, beyond any doubt, that the gap in lab and actual PHEV fuel consumption and CO₂ output is significantly larger than for gasoline or conventional cars,” they said. “All policy changes concerning PHEVs should be implemented with extreme care and considering this data.”