🔗 Share this article

PHEVs emit almost 5x greater planet-heating pollution than official figures indicate, according to a new analysis.

Growing Discrepancy Between Lab and Actual CO2 Output

Data reveals that PHEVs emit just 19% less CO₂ than traditional gas and diesel cars, based on analysis conducted by a non-profit group. That contrasts sharply with lab tests, which assumed a three-quarters reduction in emissions.

Analysts studied data from in-vehicle fuel consumption monitors of eight hundred thousand cars registered in Europe between 2021 and 2023. The team discovered that actual CO₂ emissions from PHEVs in 2023 were 4.9 times higher than lab figures, increased from 3.5 times in 2021.

“Actual CO2 output are rising, while official emissions are falling,” said a senior researcher participating in the study. “This gap is growing and poses a significant issue. Consequently, PHEVs pollute almost as much as petrol cars.”

Key Factors Behind the Emissions Gap

Researchers attributed most of the gap to overestimates of the “utility factor” – the percentage of kilometers driven in electric power relative to total distance. They found that just a quarter of travel was completed in EV mode, whereas lab assumptions assumed over four-fifths.

Even, when operating in electric mode, emission amounts were significantly higher than lab estimates. That occurred because electric motors were insufficiently powerful enough to operate alone, resulting to engines using gasoline for almost one-third of the distance covered in EV mode.

Regulatory and Financial Implications

According to estimates, the underestimation of PHEV emissions allowed several major carmaker groups to escape over €5bn in fines between 2021 and 2023, by falsely easing compliance with EU average fleet CO₂ standards.

Furthermore, drivers of PHEVs would pay about €500 more per year in running expenses than is estimated under laboratory tests.

“The strong statements that manufacturers like to make about their PHEV vehicles are clearly far from the mark,” stated a automotive expert. “Consumers are being duped into believing that by buying a PHEV, they are benefiting the environment and cutting costs. In reality, PHEVs are little improved than standard petrol and diesel vehicles in terms of energy consumption, CO₂ production, and running expenses.”

Policy Debate and Industry Lobbying

Plug-in hybrid cars have lately been drawn back into policy discussions as automakers have pressed the EU to weaken CO₂ targets. A planned prohibition on sales of new internal combustion cars in 2035 has faced heavy pressure from the automotive sector and opposition from EU countries with large automotive industries.

Several senior politicians have proposed plug-in hybrids as a potential “flexibility” solution to include in the legislation.

One external energy economics expert, who was unaffiliated with the study, described the report a “very useful contribution” after years in which segments of the automotive industry claimed there was insufficient data to accurately evaluate actual emissions.

“The results show, without question, that the difference in official and actual PHEV fuel consumption and CO₂ output is significantly larger than for petrol or diesel vehicles,” they stated. “Any policy changes concerning PHEVs should be made with extreme caution and in the light of that evidence.”