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PHEVs produce almost five times more planet-heating emissions than official figures indicate, according to a recent analysis.

Growing Gap In Lab and Actual Emissions

Statistics shows that PHEVs emit only one-fifth lower CO₂ than traditional gas and diesel vehicles, based on analysis conducted by a non-profit organization. This differs significantly with laboratory tests, which suggested a 75% decrease in emissions.

Researchers examined data from onboard fuel consumption monitors of 800,000 cars registered in Europe from 2021 and 2023. The team discovered that actual CO₂ emissions from PHEVs in 2023 were 4.9 times higher than official estimates, up from three and a half times in 2021.

“Real-world emissions are increasing, while official figures are decreasing,” stated a senior researcher involved in the report. “That discrepancy is widening and poses a serious problem. As a result, PHEVs pollute nearly as heavily as petrol vehicles.”

Primary Reasons Behind the Emissions Gap

Researchers linked the majority of the difference to overestimates of the “electric driving share” – the percentage of miles driven in electric power relative to overall distance. The team determined that only a quarter of travel was done in electric mode, whereas lab assumptions assumed over four-fifths.

Additionally, when running in EV mode, pollution amounts were significantly higher than official estimates. That happened because electric motors were not strong sufficient to function independently, leading to engines burning fossil fuels for nearly one-third of the travel covered in EV mode.

Regulatory and Financial Implications

According to calculations, the lowballing of PHEV CO2 output enabled several large automaker companies to escape over €5bn in fines between 2021 and 2023, by artificially simplifying adherence with European Union average fleet CO₂ targets.

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

“The bold statements that manufacturers often promote about their plug-in hybrid vehicles are obviously way off the mark,” stated a automotive analyst. “Consumers are being duped into thinking that by buying a PHEV, they are helping the environment and cutting money. Actually, PHEVs are little improved than standard petrol and diesel cars in terms of fuel use, CO₂ production, and running expenses.”

Policy Debate and Automotive Lobbying

Hybrid vehicles have lately been drawn back into political debates as carmakers have pressed the European Union to weaken CO₂ standards. A planned ban on sales of new internal combustion vehicles in 2035 has faced heavy lobbying from the car industry and opposition from EU countries with significant automotive industries.

Some senior politicians have suggested plug-in hybrids as a potential “compromise” solution to include in the legislation.

An external energy policy expert, who was unaffiliated with the research, described the report a “very useful contribution” after a long period in which segments of the car industry claimed there was too little data to properly assess real-world emissions.

“The results show, beyond any doubt, that the gap in official and actual PHEV fuel consumption and CO₂ output is significantly greater than for petrol or diesel vehicles,” they said. “All regulatory adjustments regarding PHEVs should be made with utmost caution and considering that evidence.”