Plug-in Hybrid Vehicles Emit Nearly as Heavily as Petrol Vehicles, Report Finds

PHEVs produce nearly 5x more global warming pollution than official figures show, according to a recent analysis.

Growing Gap Between Official and Real-World CO2 Output

Statistics shows that PHEVs emit just 19% lower CO₂ than traditional petrol and diesel cars, according to research conducted by a advocacy organization. This contrasts sharply with laboratory tests, which suggested a 75% decrease in emissions.

Analysts examined information from in-vehicle fuel consumption monitors of eight hundred thousand vehicles sold in Europe from 2021 and 2023. The team found that actual CO₂ emissions from PHEVs in 2023 were nearly five times greater than lab estimates, increased from 3.5 times in 2021.

“Actual emissions are rising, while official emissions are decreasing,” stated a lead analyst involved in the report. “This gap is growing and poses a serious issue. Consequently, PHEVs pollute nearly as much as petrol cars.”

Primary Factors Driving the Emissions Gap

Analysts linked the majority of the gap to overestimates of the “electric driving share” – the percentage of kilometers travelled in battery power relative to overall distance. They found that just a quarter of travel was completed in electric mode, while official assumptions assumed over four-fifths.

Even, when operating in EV mode, pollution amounts were significantly higher than lab estimates. This happened because electric motors were not strong enough to operate independently, leading to engines using fossil fuels for nearly a third of the travel completed in EV mode.

Policy and Financial Consequences

According to estimates, the lowballing of PHEV CO2 output enabled four large carmaker companies to avoid over €5bn in penalties from 2021 and 2023, by falsely simplifying compliance with European Union fleet-average CO₂ standards.

Furthermore, owners of PHEVs could spend approximately €500 extra per year in running expenses than would be estimated under laboratory conditions.

“The strong statements that manufacturers like to make about their PHEV cars are clearly way off the mark,” commented a automotive expert. “Buyers are being misled into thinking that by purchasing a PHEV, they are helping the planet and saving money. In reality, PHEVs are only slightly improved than regular petrol and diesel vehicles in terms of energy consumption, CO₂ emissions, and running expenses.”

Policy Debate and Industry Pressure

Plug-in hybrid cars have lately been drawn back into political discussions as automakers have pressed the EU to relax CO₂ standards. A proposed ban on sales of new internal combustion vehicles in 2035 has faced intense pressure from the automotive sector and opposition from EU countries with significant car manufacturing.

Several senior politicians have proposed PHEVs as a possible “compromise” option to introduce in the legislation.

An external energy policy specialist, who was not involved with the study, called the analysis a “very useful addition” after years in which segments of the car sector argued there was too little information to properly assess real-world emissions.

“These findings show, beyond any doubt, that the gap between official and actual PHEV fuel consumption and CO₂ emissions is much, much larger than for gasoline or diesel cars,” the expert stated. “Any regulatory changes regarding PHEVs should be made with extreme care and considering that data.”