Plug-in Hybrid Cars Pollute Almost as Heavily as Petrol Cars, Study Finds

Plug-in hybrid cars release nearly five times more planet-heating emissions than official data show, as per a recent analysis.

Growing Gap In Lab and Actual Emissions

Data shows that PHEVs release only one-fifth lower CO₂ than traditional gas and diesel cars, based on research conducted by a non-profit organization. This differs significantly with lab estimates, which assumed a 75% reduction in pollution.

Analysts studied information from in-vehicle energy use monitors of 800,000 cars registered in the EU from 2021 and 2023. The team discovered that actual CO₂ emissions from PHEVs in 2023 were 4.9 times higher than official figures, up from 3.5 times in 2021.

“Real-world emissions are increasing, while official emissions are falling,” said a lead analyst participating in the report. “That gap is widening and poses a significant issue. Consequently, PHEVs pollute almost as much as gasoline cars.”

Key Reasons Behind the Emissions Gap

Analysts linked the majority of the gap to overestimates of the “utility factor” – the percentage of miles driven in electric power relative to total distance. They determined that only a quarter of travel was done in EV mode, while official assumptions assumed 84%.

Even, when operating in electric mode, emission levels were significantly higher than lab projections. That happened because electric motors were insufficiently powerful sufficient to function alone, resulting to engines using fossil fuels for almost a third of the distance covered in EV mode.

Policy and Economic Implications

According to calculations, the lowballing of PHEV CO2 output enabled several large automaker groups to avoid more than €5bn in penalties from 2021 and 2023, by artificially easing adherence with European Union fleet-average CO₂ targets.

Furthermore, drivers of PHEVs could spend approximately €500 more per year in operating expenses than would be assumed under laboratory conditions.

“The bold claims that automakers like to make about their PHEV cars are obviously way off the mark,” stated a automotive analyst. “Buyers are being misled into thinking that by buying a PHEV, they are benefiting the environment and cutting costs. Actually, PHEVs are little better than regular gas and diesel vehicles in terms of energy use, CO₂ emissions, and operating costs.”

Policy Discussion and Automotive Pressure

Plug-in hybrid vehicles have lately been drawn again into policy discussions as carmakers have lobbied the EU to weaken CO₂ standards. A proposed prohibition on new internal combustion cars in 2035 has faced heavy pressure from the automotive industry and resistance from EU countries with large car industries.

Some senior officials have proposed PHEVs as a potential “flexibility” option to introduce in the legislation.

An external energy policy specialist, who was unaffiliated with the research, called the analysis a “highly valuable addition” after years in which parts of the automotive industry claimed there was insufficient data to properly assess real-world CO2 output.

“These findings demonstrate, without question, that the gap between official and actual PHEV fuel consumption and CO₂ output is significantly larger than for petrol or conventional cars,” the expert said. “All regulatory adjustments concerning PHEVs should be made with utmost care and in the light of that data.”