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Plug-in hybrid electric vehicles emit almost 5x more global warming emissions than official figures show, as per a recent analysis.

Widening Discrepancy In Official and Real-World CO2 Output

Data shows that PHEVs release just 19% lower CO₂ than conventional petrol and diesel cars, based on research carried out by a non-profit organization. That differs significantly with laboratory tests, which suggested a 75% reduction in emissions.

Analysts studied data from onboard energy use meters of 800,000 cars sold in Europe between 2021 and 2023. They found that actual CO₂ output from PHEVs in 2023 were nearly five times higher than lab figures, up from three and a half times in 2021.

“Real-world CO2 output are increasing, while lab-reported emissions are decreasing,” stated a senior analyst involved in the report. “That gap is widening and poses a serious problem. As a result, PHEVs pollute almost as much as petrol vehicles.”

Key Factors Driving the Emissions Gap

Analysts linked most of the gap to inflated estimates of the “utility factor” – the percentage of kilometers travelled in electric power compared to total distance. The team found that only a quarter of driving was completed in electric mode, while official estimates assumed over four-fifths.

Additionally, when operating in electric mode, emission levels were well above official projections. This occurred because electric motors were insufficiently powerful sufficient to operate alone, resulting to engines burning gasoline for nearly one-third of the distance completed in electric mode.

Regulatory and Financial Implications

Based on calculations, the lowballing of PHEV emissions allowed four major automaker groups to escape more than €5bn in fines between 2021 and 2023, by artificially easing adherence with EU average fleet CO₂ standards.

Furthermore, drivers of PHEVs could spend approximately €500 more annually in operating expenses than is assumed under laboratory conditions.

“The strong claims that manufacturers like to make about their plug-in hybrid cars are obviously way off the mark,” commented a automotive analyst. “Buyers are being duped into thinking that by buying a PHEV, they are helping the planet and saving costs. Actually, PHEVs are only slightly improved than regular petrol and diesel vehicles in terms of fuel use, CO₂ production, and running expenses.”

Policy Debate and Automotive Lobbying

Plug-in hybrid vehicles have recently been brought again into policy debates as automakers have lobbied the European Union to relax CO₂ standards. A proposed ban on new internal combustion cars in 2035 has faced intense lobbying from the automotive sector and opposition from member states with significant automotive industries.

Some senior officials have proposed plug-in hybrids as a possible “compromise” solution to include in the regulation.

One external energy policy specialist, who was not involved with the study, called the analysis a “very useful contribution” after years in which parts of the car industry argued there was too little data to accurately evaluate real-world CO2 output.

“These findings demonstrate, without question, that the difference between lab and real-world PHEV fuel consumption and CO₂ output is significantly larger than for gasoline or diesel cars,” the expert said. “All regulatory adjustments regarding PHEVs should be made with utmost care and considering that data.”