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PHEVs produce nearly 5x more planet-heating emissions than lab-reported data show, as per a recent analysis.

Growing Gap In Lab and Actual CO2 Output

Data shows that PHEVs release only 19% less CO₂ than conventional gas and diesel vehicles, based on analysis carried out by a non-profit group. This contrasts sharply with laboratory estimates, which suggested a three-quarters decrease in pollution.

Researchers examined data from in-vehicle energy use monitors of 800,000 vehicles registered in the EU between 2021 and 2023. They found that actual CO₂ emissions from PHEVs in 2023 were nearly five times greater than official estimates, up from 3.5 times in 2021.

“Real-world emissions are rising, while official emissions are decreasing,” stated a lead researcher involved in the report. “That gap is growing and poses a serious issue. Consequently, PHEVs emit nearly as much as gasoline vehicles.”

Primary Reasons Driving the Discrepancy

Researchers attributed most of the gap to overestimates of the “utility factor” – the percentage of kilometers travelled in electric mode relative to overall mileage. They determined that only a quarter of driving was completed in electric mode, while lab estimates assumed 84%.

Additionally, when operating in electric mode, pollution amounts were significantly higher than official projections. That happened because electric motors were not strong sufficient to operate alone, leading to engines burning fossil fuels for almost one-third of the distance completed in electric mode.

Policy and Financial Implications

According to calculations, the lowballing of PHEV emissions enabled four major automaker groups to avoid more than €5bn in penalties from 2021 and 2023, by artificially simplifying compliance with EU average fleet CO₂ targets.

Furthermore, drivers of PHEVs would spend approximately €500 extra 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 far from the truth,” commented a automotive analyst. “Buyers are being duped into believing that by purchasing a PHEV, they are helping the environment and cutting costs. In reality, PHEVs are only slightly better than regular gas and diesel vehicles in terms of energy use, CO₂ emissions, and operating costs.”

Policy Discussion and Automotive Lobbying

Hybrid vehicles have lately been drawn back into policy debates as carmakers have pressed the EU to weaken CO₂ standards. A planned ban on new internal combustion cars in 2035 has faced intense pressure from the automotive industry and opposition from EU countries with significant automotive industries.

Some high-level politicians have suggested plug-in hybrids as a potential “compromise” option to include in the regulation.

One independent energy economics expert, who was unaffiliated with the research, called the report a “highly valuable contribution” after years in which parts of the automotive industry argued there was insufficient data to properly evaluate real-world CO2 output.

“The results show, without question, that the difference between official and actual PHEV fuel consumption and CO₂ emissions is much, much larger than for petrol or conventional cars,” the expert said. “All regulatory changes concerning PHEVs should be implemented with utmost caution and considering that evidence.”