Plug in Hybrid Vehicles Emit Almost as Heavily as Petrol Vehicles, Report Finds

Plug-in hybrid electric vehicles release almost 5x more global warming emissions than lab-reported figures show, according to a new report.

Widening Gap Between Lab and Actual Emissions

Data reveals that PHEVs release only 19% less CO₂ than conventional gas and diesel vehicles, according to research carried out by a advocacy organization. That differs significantly with laboratory tests, which suggested a three-quarters reduction in pollution.

Analysts examined data from onboard energy use monitors of eight hundred thousand vehicles registered in the EU from 2021 and 2023. The team discovered that real-world CO₂ output from PHEVs in 2023 were 4.9 times higher than lab figures, increased from three and a half times in 2021.

“Real-world emissions are rising, while official emissions are falling,” said a senior analyst involved in the report. “That gap is widening and creates a serious issue. As a result, PHEVs emit almost as much as petrol cars.”

Key Reasons Driving the Emissions Gap

Analysts linked most of the gap to inflated estimates of the “electric driving share” – the percentage of kilometers driven in battery mode compared to total distance. The team found that only a quarter of driving was done in electric mode, whereas lab assumptions suggested over four-fifths.

Even, when running in EV mode, pollution levels were well above lab projections. That occurred because electric motors were not strong enough to function independently, resulting to engines burning fossil fuels for almost one-third of the travel completed in electric mode.

Policy and Financial Consequences

Based on estimates, the lowballing of PHEV CO2 output allowed four major carmaker companies to escape over €5bn in fines between 2021 and 2023, by artificially simplifying compliance with EU fleet-average CO₂ standards.

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

“The strong statements that automakers like to make about their PHEV cars are obviously way off the truth,” commented a automotive expert. “Buyers are being duped into believing that by purchasing a PHEV, they are benefiting the environment and saving costs. Actually, PHEVs are little better than standard gas and diesel cars in terms of fuel consumption, CO₂ emissions, and operating expenses.”

Policy Debate and Automotive Lobbying

Plug-in hybrid vehicles have lately been brought back into political discussions as automakers have lobbied the European Union to weaken CO₂ standards. A proposed prohibition on sales of new combustion engine cars in 2035 has faced heavy pressure from the car industry and opposition from member states with large automotive industries.

Some senior politicians have suggested plug-in hybrids as a potential “flexibility” option to include in the regulation.

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

“The results demonstrate, without question, that the difference between lab and real-world PHEV fuel consumption and CO₂ output is much, much larger than for petrol or conventional cars,” the expert said. “Any regulatory adjustments concerning PHEVs should be implemented with extreme care and considering this evidence.”