Plug-in Hybrid electric Vehicles Pollute Nearly as Much as Petrol Vehicles, Study Finds

Plug-in hybrid electric vehicles produce nearly five times greater global warming emissions than lab-reported figures show, as per a new analysis.

Growing Gap In Official and Actual Emissions

Statistics reveals that PHEVs release just 19% lower CO₂ than conventional gas and diesel vehicles, according to analysis conducted by a advocacy organization. That contrasts sharply with laboratory estimates, which suggested a three-quarters reduction in emissions.

Analysts examined data from onboard fuel consumption monitors of eight hundred thousand vehicles registered in the EU between 2021 and 2023. They found that real-world CO₂ emissions from PHEVs in 2023 were 4.9 times greater than lab estimates, up from 3.5 times in 2021.

“Real-world emissions are increasing, while official figures are decreasing,” said a lead analyst involved in the report. “That gap is widening and poses a serious problem. As a result, PHEVs pollute almost as heavily as petrol vehicles.”

Primary Factors Driving the Discrepancy

Researchers attributed most of the difference to overestimates of the “utility factor” – the percentage of miles driven in electric mode compared to overall mileage. They determined that only 27% of driving was completed in EV mode, whereas official estimates assumed over four-fifths.

Additionally, when operating in EV mode, emission amounts were well above lab estimates. This happened because EV motors were not strong sufficient to operate independently, leading to engines using gasoline for nearly one-third of the distance covered in electric mode.

Regulatory and Financial Implications

Based on estimates, the lowballing of PHEV emissions allowed several large carmaker groups to avoid more than €5bn in penalties between 2021 and 2023, by artificially easing adherence with EU average fleet CO₂ standards.

Additionally, owners of PHEVs could pay about €500 extra per year in operating costs than is estimated under lab tests.

“The bold claims that automakers often promote about their PHEV vehicles are clearly way off the truth,” stated a automotive expert. “Buyers 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 vehicles in terms of fuel consumption, CO₂ emissions, and operating expenses.”

Policy Debate and Industry Pressure

Hybrid cars have lately been drawn again into policy debates as automakers have pressed the European Union to weaken CO₂ standards. A proposed prohibition on sales of new combustion engine vehicles in 2035 has faced intense pressure from the car sector and opposition from EU countries with large car manufacturing.

Some high-level officials have suggested PHEVs as a potential “compromise” option to introduce in the regulation.

One external energy economics expert, who was not involved with the research, described the analysis a “highly valuable contribution” after years in which parts of the automotive sector claimed there was insufficient information to accurately assess real-world CO2 output.

“These findings demonstrate, without question, that the difference between lab and real-world PHEV energy use and CO₂ output is significantly larger than for petrol or conventional cars,” they said. “All policy adjustments regarding PHEVs should be implemented with utmost care and considering that evidence.”